tag:text.Baldanders.info,2026-09-24:/tags 2026-09-24T21:32:18+09:00 帰ってきた「しっぽのさきっちょ」 https://text.baldanders.info/images/avatar.jpg https://text.baldanders.info/images/avatar.jpg tag:text.Baldanders.info,2026-09-24:/remark/2026/09/fediverse-author/ 2026-09-24T12:32:18+00:00 2026-09-24T12:42:15+00:00

これは以前からある rel="me" を使った Web サイト認証とは異なる。ブログ等を運営している方は，検討してみてもいいかもしれない。

Spiegel https://baldanders.info/profile/ <p>正式には Mastodon v4.3 からの機能らしいのだが Web ページの <code>&lt;meta&gt;</code> 要素に著者情報として Fediverse/Mastodon アカウントを設定できるようになっている。</p> <ul> <li><a href="https://blog.joinmastodon.org/2024/10/mastodon-4.3/" target="_blank">Mastodon 4.3</a></li> <li><a href="https://blog.joinmastodon.org/2024/07/highlighting-journalism-on-mastodon/" target="_blank">Highlighting journalism on Mastodon</a></li> </ul> <figure lang="en"> <blockquote cite="https://blog.joinmastodon.org/2024/07/highlighting-journalism-on-mastodon/"><p>We’ve decided to create a new kind of OpenGraph tag—the same kind of tags you have on your website to determine which thumbnail image will appear on the preview for the page when shared on Discord, iMessage, or Mastodon. It looks like this: <code>&lt;meta name=&quot;fediverse:creator&quot; content=&quot;@Gargron@mastodon.social&quot; /&gt;</code>.</p> <p>The handle can be any fediverse account, not just Mastodon. That includes Flipboard, Threads, WordPress (with the ActivityPub plugin installed), PeerTube, Pixelfed, and many others. It will work with and without the leading at-symbol for the handle. If multiple tags are present on the page, the first one will be displayed, but we may add support for showing multiple authors in the future. We intend to propose a specification draft for other ActivityPub platforms in the coming weeks.</p> </blockquote> <figcaption><div>via <q><a href="https://blog.joinmastodon.org/2024/07/highlighting-journalism-on-mastodon/">Highlighting journalism on Mastodon</a></q></div></figcaption> </figure> <p>これは以前からある <code>rel=&quot;me&quot;</code> を使った Web サイト認証とは異なる。</p> <p>たとえば Mastodon アカウントが <code>@username@mstdn.example.com</code> なら Web ページの <code>&lt;head&gt;</code> 要素内に以下の <code>&lt;meta&gt;</code> 要素を追記する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">meta</span> <span class="na">name</span><span class="o">=</span><span class="s">&#34;fediverse:creator&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;@username@mstdn.example.com&#34;</span><span class="p">&gt;</span> </span></span></code></pre></div><p>上の引用文では Open Graph 語彙の新種みたいに書かれているが，厳密な <a href="https://baldanders.info/spiegel/rdfa/" target="_blank" title="RDFa 入門 — 旧コンテンツ置き場 | Baldanders.info">RDFa</a> の語彙があるわけではなく，固定名 <code>fediverse:creator</code> のデータを <code>name</code> 属性と <code>content</code> 属性の組で記述しているに過ぎない。 どちらかというと <a href="https://text.baldanders.info/remark/2017/10/twitter-card-metadata/" target="_blank" title="Twitter Card メタデータに対応した">Twitter Card の仕組み</a>に近いかな。</p> <p>上手く設定できればリンクプレビューに著者情報が表示される。 こんな感じ。</p> <figure style='margin:0 auto;text-align:center;'><a href="https://goark.fedicity.net/@spiegel/117323386403107012"><img src="./post.png" srcset="./post.png 588w" sizes="(min-width:600px) 500px, 80vw" alt="リンクプレビュー表示例" loading="lazy"></a><figcaption><div><a href="https://goark.fedicity.net/@spiegel/117323386403107012">リンクプレビュー表示例</a></div></figcaption> </figure> <p>全く関係ない Web ページに著者情報を設定されるのは困るので，ユーザのプロフィール設定で有効なドメインを指定する。</p> <figure> <blockquote class="nobox" style='margin:0 auto;text-align:center;' cite="./profile.png"> <a href="./profile.png"><img src="./profile.png" srcset="./profile.png 782w" sizes="(min-width:600px) 500px, 80vw" alt="認証 - プロフィール" loading="lazy"></a> </blockquote> <figcaption><div><q><a href="./profile.png">認証 - プロフィール</a></q>より</div></figcaption> </figure> <p>上の例なら <a href="https://baldanders.info/" target="_blank"><code>baldanders.info</code></a> および <a href="https://text.baldanders.info/" target="_blank"><code>text.baldanders.info</code></a> ドメインの Web ページに対してのみ著者情報が有効になる。</p> <p>ブログ等を運営している方で自力で <code>&lt;meta&gt;</code> 要素を設置可能であれば，検討してみてもいいんじゃないだろうか。</p> tag:text.Baldanders.info,2026-09-16:/golang/strip-html-tags/ 2026-09-16T03:17:57+00:00 2026-09-16T03:18:31+00:00

正規表現でタグを除去する / Tokenizer を使ってタグを除去する

Spiegel https://baldanders.info/profile/ <p>たとえば</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl">This is a <span class="p">&lt;</span><span class="nt">strong</span><span class="p">&gt;</span>sample<span class="p">&lt;/</span><span class="nt">strong</span><span class="p">&gt;</span> text </span></span><span class="line"><span class="cl">with <span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;#&#34;</span><span class="p">&gt;</span>HTML<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span> tags. </span></span></code></pre></div><p>というテキストデータが与えられた場合に <code>&lt;strong&gt;</code> や <code>&lt;a&gt;</code> といった HTML タグを除去することを考える。</p> <h2>正規表現でタグを除去する</h2> <p>単純に <code>&lt;...&gt;</code> の文字列パターンを除去できればいいのであれば正規表現が使える。 こんな感じ。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kn">package</span><span class="w"> </span><span class="nx">striptag</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;html&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;regexp&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="c1">// StripTagsRegexp removes all HTML tags from the input string and unescapes any HTML entities.</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">StripTagsRegexp</span><span class="p">(</span><span class="nx">s</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">re</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">regexp</span><span class="p">.</span><span class="nf">MustCompile</span><span class="p">(</span><span class="s">`&lt;[^&gt;]*&gt;`</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">html</span><span class="p">.</span><span class="nf">UnescapeString</span><span class="p">(</span><span class="nx">re</span><span class="p">.</span><span class="nf">ReplaceAllString</span><span class="p">(</span><span class="nx">s</span><span class="p">,</span><span class="w"> </span><span class="s">&#34;&#34;</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p>実際に動かしてみよう。 入力テキストを</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kn">package</span><span class="w"> </span><span class="nx">example</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">const</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">Text1</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="s">`This is a &lt;strong&gt;sample&lt;/strong&gt; text </span></span></span><span class="line"><span class="cl"><span class="s">with &lt;a href=&#34;#&#34;&gt;HTML&lt;/a&gt; tags.`</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span></code></pre></div><p>と定義しておいて，次のように <code>main()</code> 関数を定義する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="cp">//go:build ignore</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">package</span><span class="w"> </span><span class="nx">main</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;striptag&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;striptag/example&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nb">println</span><span class="p">(</span><span class="nx">striptag</span><span class="p">.</span><span class="nf">StripTagsRegexp</span><span class="p">(</span><span class="nx">example</span><span class="p">.</span><span class="nx">Text1</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p>これを実行すると</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ go run sample1a.go </span></span><span class="line"><span class="cl">This is a sample text </span></span><span class="line"><span class="cl">with HTML tags. </span></span></code></pre></div><p>と出力される。 ここまでは問題ない。 問題は入力テキストに異物が混ざってた場合。 たとえば</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kd">const</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">Text2</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="s">`This is a &lt;strong&gt;sample&lt;/strong&gt; text </span></span></span><span class="line"><span class="cl"><span class="s">with &lt;a href=&#34;#&#34;&gt;HTML&lt;/a&gt; tags.&lt;script&gt;alert(&#34;XSS&#34;)&lt;/script&gt;`</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span></code></pre></div><p>のような感じ（末尾に <code>&lt;script&gt;</code> タグがある）。 これを <code>StripTagsRegexp()</code> 関数で処理すると</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">This is a sample text </span></span><span class="line"><span class="cl">with HTML tags.alert(&#34;XSS&#34;) </span></span></code></pre></div><p>のように <code>&lt;script&gt;</code> タグの中身が露出してしまう。</p> <h2>Tokenizer を使ってタグを除去する</h2> <p>これを正規表現で対処するのは（やれないことはないだろうが）かなり面倒な気がするので，やり方を変えて <a href="https://pkg.go.dev/golang.org/x/net/html" target="_blank" title="html package - golang.org/x/net/html - Go Packages"><code>golang.org/x/net/html</code></a> パッケージの <code>Tokenizer</code> を使うことにする。 こんな感じかな。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kn">package</span><span class="w"> </span><span class="nx">striptag</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;errors&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;html&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;io&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;strings&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">ghtml</span><span class="w"> </span><span class="s">&#34;golang.org/x/net/html&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="c1">// skipTags defines the HTML tags whose content should be skipped when stripping tags.</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">var</span><span class="w"> </span><span class="nx">skipTags</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="kd">map</span><span class="p">[</span><span class="kt">string</span><span class="p">]</span><span class="kt">bool</span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;script&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;style&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;noscript&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;iframe&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;object&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;embed&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;textarea&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;title&#34;</span><span class="p">:</span><span class="w"> </span><span class="kc">true</span><span class="p">,</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="c1">// StripTagsTokenizer removes HTML tags from the input string while skipping</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="c1">// the content of certain tags defined in skipTags.</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">StripTagsTokenizer</span><span class="p">(</span><span class="nx">s</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">error</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">tokenizer</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nf">NewTokenizer</span><span class="p">(</span><span class="nx">strings</span><span class="p">.</span><span class="nf">NewReader</span><span class="p">(</span><span class="nx">s</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="kd">var</span><span class="w"> </span><span class="nx">b</span><span class="w"> </span><span class="nx">strings</span><span class="p">.</span><span class="nx">Builder</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">b</span><span class="p">.</span><span class="nf">Grow</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="nx">s</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">tt</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Next</span><span class="p">()</span><span class="w"> </span><span class="c1">// get the next token type</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">switch</span><span class="w"> </span><span class="nx">tt</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">ErrorToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle error token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">errors</span><span class="p">.</span><span class="nf">Is</span><span class="p">(</span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Err</span><span class="p">(),</span><span class="w"> </span><span class="nx">io</span><span class="p">.</span><span class="nx">EOF</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">b</span><span class="p">.</span><span class="nf">String</span><span class="p">(),</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="c1">// return the accumulated text at the end of input</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="s">&#34;&#34;</span><span class="p">,</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Err</span><span class="p">()</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">StartTagToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle start tag token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">t</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Token</span><span class="p">()</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipTags</span><span class="p">[</span><span class="nx">t</span><span class="p">.</span><span class="nx">Data</span><span class="p">]</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">skipDepth</span><span class="o">++</span><span class="w"> </span><span class="c1">// start skipping content of this tag</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">EndTagToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle end tag token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">t</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Token</span><span class="p">()</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="p">&gt;</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="o">&amp;&amp;</span><span class="w"> </span><span class="nx">skipTags</span><span class="p">[</span><span class="nx">t</span><span class="p">.</span><span class="nx">Data</span><span class="p">]</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">skipDepth</span><span class="o">--</span><span class="w"> </span><span class="c1">// stop skipping one level of skipped content</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">TextToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle text token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">b</span><span class="p">.</span><span class="nf">WriteString</span><span class="p">(</span><span class="nx">html</span><span class="p">.</span><span class="nf">UnescapeString</span><span class="p">(</span><span class="nb">string</span><span class="p">(</span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Text</span><span class="p">())))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p>これで <code>&lt;script&gt; ... &lt;/script&gt;</code> の中身をスキップできる筈。 試してみよう。 <code>main()</code> 関数を</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="cp">//go:build ignore</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">package</span><span class="w"> </span><span class="nx">main</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;fmt&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;os&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;striptag&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;striptag/example&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="nx">out</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">striptag</span><span class="p">.</span><span class="nf">StripTagsTokenizer</span><span class="p">(</span><span class="nx">example</span><span class="p">.</span><span class="nx">Text2</span><span class="p">)</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="nx">fmt</span><span class="p">.</span><span class="nf">Fprintln</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nx">Stderr</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="p">)</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">out</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p>と書き直して実行する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ go run sample2b.go </span></span><span class="line"><span class="cl">This is a sample text </span></span><span class="line"><span class="cl">with HTML tags. </span></span></code></pre></div><p>おー。 上手く行ったかな。</p> <h3>改行タグを改行コードに変換する</h3> <p>応用として，前節の <code>StripTagsTokenizer()</code> 関数に <code>&lt;br&gt;</code> タグを改行コードに変換する機能を追加する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line hl"><span class="cl"><span class="c1">// changeBrToNewline handles the &lt;br&gt; tag by converting it to a newline character in the output.</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">changeBrToNewline</span><span class="p">(</span><span class="nx">t</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">Token</span><span class="p">,</span><span class="w"> </span><span class="nx">b</span><span class="w"> </span><span class="o">*</span><span class="nx">strings</span><span class="p">.</span><span class="nx">Builder</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">t</span><span class="p">.</span><span class="nx">Data</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="s">&#34;br&#34;</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="c1">// Handle &lt;br&gt; as a line break.</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="nx">b</span><span class="p">.</span><span class="nf">WriteByte</span><span class="p">(</span><span class="sc">&#39;\n&#39;</span><span class="p">)</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="c1">// StripTagsTokenizer removes HTML tags from the input string while skipping</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="c1">// the content of certain tags defined in skipTags.</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">StripTagsTokenizer</span><span class="p">(</span><span class="nx">s</span><span class="w"> </span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="p">(</span><span class="kt">string</span><span class="p">,</span><span class="w"> </span><span class="kt">error</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">tokenizer</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nf">NewTokenizer</span><span class="p">(</span><span class="nx">strings</span><span class="p">.</span><span class="nf">NewReader</span><span class="p">(</span><span class="nx">s</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="kd">var</span><span class="w"> </span><span class="nx">b</span><span class="w"> </span><span class="nx">strings</span><span class="p">.</span><span class="nx">Builder</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">b</span><span class="p">.</span><span class="nf">Grow</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="nx">s</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">tt</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Next</span><span class="p">()</span><span class="w"> </span><span class="c1">// get the next token type</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">switch</span><span class="w"> </span><span class="nx">tt</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">ErrorToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle error token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">errors</span><span class="p">.</span><span class="nf">Is</span><span class="p">(</span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Err</span><span class="p">(),</span><span class="w"> </span><span class="nx">io</span><span class="p">.</span><span class="nx">EOF</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">b</span><span class="p">.</span><span class="nf">String</span><span class="p">(),</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="c1">// return the accumulated text at the end of input</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="s">&#34;&#34;</span><span class="p">,</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Err</span><span class="p">()</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">StartTagToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle start tag token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">t</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Token</span><span class="p">()</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipTags</span><span class="p">[</span><span class="nx">t</span><span class="p">.</span><span class="nx">Data</span><span class="p">]</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">skipDepth</span><span class="o">++</span><span class="w"> </span><span class="c1">// start skipping content of this tag</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="nf">changeBrToNewline</span><span class="p">(</span><span class="nx">t</span><span class="p">,</span><span class="w"> </span><span class="o">&amp;</span><span class="nx">b</span><span class="p">)</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">SelfClosingTagToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle self-closing tag token</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="nx">t</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Token</span><span class="p">()</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="nf">changeBrToNewline</span><span class="p">(</span><span class="nx">t</span><span class="p">,</span><span class="w"> </span><span class="o">&amp;</span><span class="nx">b</span><span class="p">)</span><span class="w"> </span></span></span><span class="line hl"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">EndTagToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle end tag token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">t</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Token</span><span class="p">()</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="p">&gt;</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="o">&amp;&amp;</span><span class="w"> </span><span class="nx">skipTags</span><span class="p">[</span><span class="nx">t</span><span class="p">.</span><span class="nx">Data</span><span class="p">]</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">skipDepth</span><span class="o">--</span><span class="w"> </span><span class="c1">// stop skipping one level of skipped content</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">case</span><span class="w"> </span><span class="nx">ghtml</span><span class="p">.</span><span class="nx">TextToken</span><span class="p">:</span><span class="w"> </span><span class="c1">// handle text token</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">skipDepth</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">b</span><span class="p">.</span><span class="nf">WriteString</span><span class="p">(</span><span class="nx">html</span><span class="p">.</span><span class="nf">UnescapeString</span><span class="p">(</span><span class="nb">string</span><span class="p">(</span><span class="nx">tokenizer</span><span class="p">.</span><span class="nf">Text</span><span class="p">())))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p>修正した <code>StripTagsTokenizer()</code> 関数を使って以下のテキストを処理する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kd">const</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">Text3</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="s">`This is a &lt;strong&gt;sample&lt;/strong&gt; text&lt;br&gt;with &lt;a href=&#34;#&#34;&gt;HTML&lt;/a&gt; tags.&lt;script&gt;alert(&#34;XSS&#34;)&lt;/script&gt;`</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span></code></pre></div><p>処理結果はこんな感じ。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">This is a sample text </span></span><span class="line"><span class="cl">with HTML tags. </span></span></code></pre></div><p><code>text&lt;br&gt;with</code> の <code>&lt;br&gt;</code> タグは改行に変換されていることが確認できた。</p> <p>ここまできたら <code>&lt;p&gt;</code> のようなブロック要素にも対応したいところだけど，実際にブロック要素か否かはスタイル情報に依存するため，今回は割愛する。</p> <h2>参考図書</h2> <p><div class="hreview"> <div class="photo"><a href="https://www.maruzen-publishing.co.jp/book/b10112161.html"><img src="https://text.baldanders.info/images/thumbs/9e8d8f717b1d1d85b0da7f07cb10a83b78d4227f.jpg" width="110" alt="thumbs"></a></div> <dl> <dt class="item"><a class="fn url" href="https://www.maruzen-publishing.co.jp/book/b10112161.html">プログラミング言語Go - 丸善出版 理工・医学・人文社会科学の専門書出版社</a></dt> <dd>明解で効率的なプログラムを描くための書。 柴田　芳樹 訳</dd> <dd>&nbsp;</dd> <dd>Release <abbr class="release-date" title="2016-06-15">2016-06-15</abbr></dd> <dd>評価<abbr class="rating fa-sm" title="5">&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i></abbr></dd> </dl> <p class="description"><strong>[Comment]</strong> 著者のひとりは，あの “K&R” の K のほうである。この本は Go 言語の教科書と言ってもいいだろう。と思ったら絶版状態らしい（2025-01 現在）。復刊を望む！</p> <p class="powered-by">Powered by <a href="https://github.com/spiegel-im-spiegel/linkcard">linkcard</a></p> </div> <!-- プログラミング言語Go --> <div class="hreview"> <div class="photo"><a href="https://www.amazon.co.jp/dp/B0CFL1DK8Q?tag=baldandersinf-22&amp;linkCode=ogi&amp;th=1&amp;psc=1"><img src="https://m.media-amazon.com/images/I/51BmDUG6D0L._SL160_.jpg" width="125" alt="photo"></a></div> <dl> <dt class="item"><a class="fn url" href="https://www.amazon.co.jp/dp/B0CFL1DK8Q?tag=baldandersinf-22&amp;linkCode=ogi&amp;th=1&amp;psc=1">Go言語 100Tips ありがちなミスを把握し、実装を最適化する impress top gearシリーズ</a></dt> <dd>Teiva Harsanyi (著), 柴田 芳樹 (著)</dd> <dd>インプレス 2023-08-18 (Release 2023-08-18)</dd> <dd>Kindle版</dd> <dd>B0CFL1DK8Q (ASIN)</dd> <dd>評価<abbr class="rating fa-sm" title="4">&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="far fa-star"></i></abbr></dd> </dl> <p class="description"><strong>[Comment]</strong> <a href="https://book.impress.co.jp/books/1122101133">版元</a>で PDF 版を購入可能。事実上の Effective Go とも言える充実の内容。オリジナルは敢えてタイトルに “tips” という単語を入れるのを避けたのに邦題が「100 Tips」とかなっていて，原作者がお怒りとの噂（あくまで噂）</p> <p class="powered-by">reviewed by <a href='#maker' class='reviewer'>Spiegel</a> on <abbr class="dtreviewed" title="2023-08-18">2023-08-18</abbr> (powered by <a href="https://affiliate.amazon.co.jp/assoc_credentials/home">PA-APIv5</a>)</p> </div> <!-- Go言語 100Tips --> <div class="hreview"> <div class="photo"><a href="https://www.amazon.co.jp/dp/B0DNYMMBBQ?tag=baldandersinf-22&amp;linkCode=ogi&amp;th=1&amp;psc=1"><img src="https://m.media-amazon.com/images/I/51wZEHUKZiL._SL160_.jpg" width="125" alt="photo"></a></div> <dl> <dt class="item"><a class="fn url" href="https://www.amazon.co.jp/dp/B0DNYMMBBQ?tag=baldandersinf-22&amp;linkCode=ogi&amp;th=1&amp;psc=1">Go言語で学ぶ並行プログラミング　他言語にも適用できる原則とベストプラクティス impress top gearシリーズ</a></dt> <dd>James Cutajar (著), 柴田 芳樹 (著)</dd> <dd>インプレス 2024-12-04 (Release 2024-12-04)</dd> <dd>Kindle版</dd> <dd>B0DNYMMBBQ (ASIN)</dd> <dd>評価<abbr class="rating fa-sm" title="5">&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i>&nbsp;<i class="fas fa-star"></i></abbr></dd> </dl> <p class="description"><strong>[Comment]</strong> <a href="https://technical-book-reading-2.connpass.com/event/337562/">読書会</a>のために購入。インプレス社の本は Kindle 版より版元で <a href="https://book.impress.co.jp/books/1123101144">PDF 版</a>を買うのがオススメ。「並行処理」について原理的な解説から丁寧に書かれている。 Go で解説されているが Go 以外の言語でも応用できる。 </p> <p class="powered-by">reviewed by <a href='#maker' class='reviewer'>Spiegel</a> on <abbr class="dtreviewed" title="2025-01-25">2025-01-25</abbr> (powered by <a href="https://affiliate.amazon.co.jp/assoc_credentials/home">PA-APIv5</a>)</p> </div> <!-- Go言語で学ぶ並行プログラミング --></p> tag:text.Baldanders.info,2026-08-10:/remark/2026/08/ogp-article-meta/ 2026-08-10T06:20:48+00:00 2026-08-10T06:26:24+00:00

OGP は相変わらずセマンティック・ウェブからかけ離れたところにいるのがいい感じである（笑）

Spiegel https://baldanders.info/profile/ <p>他所のブログ記事を眺めてたら <code>&lt;head&gt;</code> 要素内のメタデータに</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">meta</span> <span class="na">property</span><span class="o">=</span><span class="s">&#34;article:tag&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;foo&#34;</span><span class="p">&gt;</span> </span></span></code></pre></div><p>みたいな記述が見える。 <code>article</code> なんてあったか？ と思い，調べてみたら，どうやら <a href="https://ogp.me/" target="_blank" title="The Open Graph protocol">OGP</a> の中で定義されている語彙（vocabulary）のようだ。</p> <h2>オブジェクトタイプに article を指定する</h2> <p><code>article</code> を使うためには <code>prefix</code> に <code>article</code> の語彙を定義し <code>og:type</code> に <code>article</code> を指定する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">html</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">head</span> <span class="na">prefix</span><span class="o">=</span><span class="s">&#34;og: http://ogp.me/ns# article: http://ogp.me/ns/article#&#34;</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> ... </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">meta</span> <span class="na">property</span><span class="o">=</span><span class="s">&#34;og:type&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;article&#34;</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> ... </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">head</span><span class="p">&gt;</span> </span></span></code></pre></div><p><code>content</code> 属性は本来リテラルデータを指すので内容に（RDF 上の）意味はないのだが，どうやらただの文字列ではなく， Web 上のリソースを指定しなければいけないようだ。 したがって <code>&lt;head&gt;</code> 要素に</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">meta</span> <span class="na">property</span><span class="o">=</span><span class="s">&#34;og:type&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;article&#34;</span><span class="p">&gt;</span> </span></span></code></pre></div><p>と書きたければ <code>&lt;head&gt;</code> 要素の <code>prefix</code> 属性を使って</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">head</span> <span class="na">prefix</span><span class="o">=</span><span class="s">&#34;og: http://ogp.me/ns# article: http://ogp.me/ns/article#&#34;</span><span class="p">&gt;</span> ... <span class="p">&lt;/</span><span class="nt">head</span><span class="p">&gt;</span> </span></span></code></pre></div><p>のように記述する必要がある。 まぁ RDFa の設計思想的には間違ってるけどね。 もう，私は気にしないことにしている。</p> <p><a href="https://ogp.me/" target="_blank" title="The Open Graph protocol">OGP</a> では <code>article</code> を含め，以下の語彙が定義されている。</p> <div class="smaller"><table> <thead> <tr> <th style="text-align: left">IRI</th> <th style="text-align: left">resource</th> <th style="text-align: left">types</th> </tr> </thead> <tbody> <tr> <td style="text-align: left"><code>music</code></td> <td style="text-align: left"><code>https://ogp.me/ns/music#</code></td> <td style="text-align: left"><code>music.song</code>, <code>music.album</code>, <code>music.playlist</code>, <code>music.radio_station</code></td> </tr> <tr> <td style="text-align: left"><code>video</code></td> <td style="text-align: left"><code>https://ogp.me/ns/video#</code></td> <td style="text-align: left"><code>video.movie</code>, <code>video.episode</code>, <code>video.tv_show</code>, <code>video.other</code></td> </tr> <tr> <td style="text-align: left"><code>article</code></td> <td style="text-align: left"><code>http://ogp.me/ns/article#</code></td> <td style="text-align: left"><code>article</code></td> </tr> <tr> <td style="text-align: left"><code>book</code></td> <td style="text-align: left"><code>http://ogp.me/ns/book#</code></td> <td style="text-align: left"><code>book</code></td> </tr> <tr> <td style="text-align: left"><code>payment</code></td> <td style="text-align: left"><code>http://ogp.me/ns/payment#</code></td> <td style="text-align: left"><code>payment.link</code></td> </tr> <tr> <td style="text-align: left"><code>profile</code></td> <td style="text-align: left"><code>http://ogp.me/ns/profile#</code></td> <td style="text-align: left"><code>profile</code></td> </tr> <tr> <td style="text-align: left"><code>website</code></td> <td style="text-align: left"><code>http://ogp.me/ns/website#</code></td> <td style="text-align: left"><code>website</code></td> </tr> </tbody> </table> </div> <p>これ以外の語彙が欲しいなら独自に定義するしかない。</p> <h2>article のメタデータ</h2> <p><code>article</code> の語彙で使えるメタデータは以下の通り</p> <table> <thead> <tr> <th style="text-align: left">property</th> <th style="text-align: left">content</th> <th style="text-align: left">description</th> </tr> </thead> <tbody> <tr> <td style="text-align: left"><code>article:published_time</code></td> <td style="text-align: left">ISO 8601 形式の日時</td> <td style="text-align: left">記事の公開日時</td> </tr> <tr> <td style="text-align: left"><code>article:modified_time</code></td> <td style="text-align: left">ISO 8601 形式の日時</td> <td style="text-align: left">記事の最終更新日時</td> </tr> <tr> <td style="text-align: left"><code>article:expiration_time</code></td> <td style="text-align: left">ISO 8601 形式の日時</td> <td style="text-align: left">記事の有効期限</td> </tr> <tr> <td style="text-align: left"><code>article:author</code></td> <td style="text-align: left"><code>profile</code> リソース</td> <td style="text-align: left">記事の著者情報</td> </tr> <tr> <td style="text-align: left"><code>article:section</code></td> <td style="text-align: left">文字列</td> <td style="text-align: left">記事のセクション（カテゴリ）</td> </tr> <tr> <td style="text-align: left"><code>article:tag</code></td> <td style="text-align: left">文字列</td> <td style="text-align: left">記事のタグ</td> </tr> </tbody> </table> <p><code>article:author</code> に正しくリソース（通常は URI）を指定している Web ページを見たことがない（笑） みんな名前を文字列で書いてるっぽい。 私も <code>profile</code> の語彙でわざわざメタデータを書く気にならないので，名前の文字列をセットしている。 文法的には <code>content</code> 属性はリテラル値なので，ただの文字列でも文法上はエラーにならないのだが。</p> <p><code>article:author</code> や <code>article:tag</code> が複数ある場合は <code>&lt;meta&gt;</code> 要素を複数書けばよい。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">meta</span> <span class="na">property</span><span class="o">=</span><span class="s">&#34;article:tag&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;foo&#34;</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">meta</span> <span class="na">property</span><span class="o">=</span><span class="s">&#34;article:tag&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;bar&#34;</span><span class="p">&gt;</span> </span></span></code></pre></div><p><code>article:section</code> や <code>article:tag</code> には文字列を指定するとあるが，それって意味なくね？ 普通はセクションやタグの情報を示すリソースを示すものなんじゃないのか？</p> <h2>OGP は，やっぱり OGP だった</h2> <p>以上を踏まえて，このブログサイトも <code>&lt;head&gt;</code> 要素に <a href="https://ogp.me/" target="_blank" title="The Open Graph protocol">OGP</a> の <code>article</code> メタデータを追加している。 まぁ <code>article</code> メタデータがどのくらい活用されているのかは分からないけど。 しばらくは様子見ということで。</p> <p><a href="https://ogp.me/" target="_blank" title="The Open Graph protocol">OGP</a> は（RDFa に則ってるのに）相変わらずセマンティック・ウェブからかけ離れたところにいるのがいい感じである（笑）</p> <h2>ブックマーク</h2> <ul> <li> <p><a href="https://www.w3.org/TR/rdfa-primer/" target="_blank">RDFa 1.1 Primer - Third Edition</a></p> </li> <li> <p><a href="https://www.w3.org/TR/rdfa-core/" target="_blank">RDFa Core 1.1 - Third Edition</a></p> </li> <li> <p><a href="https://www.w3.org/TR/html-rdfa/" target="_blank">HTML+RDFa 1.1 - Second Edition</a></p> </li> <li> <p><a href="https://webtech.fukushimaku.jp/kiji/ogp-open-graph-protocol-knowledge.html" target="_blank">アナタの知らないOGPタグ</a></p> </li> <li> <p><a href="https://text.baldanders.info/remark/2017/10/twitter-card-metadata/" target="_blank">Twitter Card メタデータに対応した</a></p> </li> </ul> <!-- eof --> tag:text.Baldanders.info,2018-02-17:/golang/using-blackfriday-v2/ 2018-02-17T06:44:07+00:00 2020-03-06T11:35:54+00:00

調子に乗ってプレビュー・ツールも作ってみた。

Spiegel https://baldanders.info/profile/ <p>この前 <a href="https://text.baldanders.info/remark/2018/02/from-markdown-to-html/" target="_blank">markdown テキスト変換ツールの物色</a>を行っていたのだが，この中で <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">blackfriday</a> パッケージがなかなか面白そうなのでちょっと遊んでみることにした。</p> <h2><a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">blackfriday</a>.v2</h2> <p>現在 <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">blackfriday</a> は v2 系が最新版で，作者も v2 を推奨しているみたいなのだが，軽くググってみるかぎり v2 を使っているところを見かけない。 このブログのサイト生成ツールである <a href="https://gohugo.io/" target="_blank" title="The world’s fastest framework for building websites | Hugo">Hugo</a> も 1.x 系みたいだし。 おそらくインタフェースが違うだけで（HTML に変換する限りは）性能的にはあまり変わらないため需要がないのかもしれない。</p> <p>v2 系は <a href="https://github.com/" target="_blank">GitHub</a> ではなく以下から取得するのがいいらしい。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ go get -u gopkg.in/russross/blackfriday.v2 </span></span></code></pre></div><p><a href="https://golang.github.io/dep/" target="_blank" title="dep · Dependency management for Go">dep</a> を使うなら <code>dep ensure -add</code> コマンドで取り込むか <a href="https://golang.github.io/dep/docs/Gopkg.toml.html" target="_blank" title="Gopkg.toml · dep"><code>Gopkg.toml</code></a> ファイルに以下の記述を追加する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-toml" data-lang="toml"><span class="line"><span class="cl"><span class="p">[[</span><span class="nx">constraint</span><span class="p">]]</span> </span></span><span class="line"><span class="cl"> <span class="nx">name</span> <span class="p">=</span> <span class="s2">&#34;gopkg.in/russross/blackfriday.v2&#34;</span> </span></span><span class="line"><span class="cl"> <span class="nx">version</span> <span class="p">=</span> <span class="s2">&#34;~2.0.0&#34;</span> </span></span></code></pre></div><p>HTML への変換はこんな感じに書ける。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kn">package</span><span class="w"> </span><span class="nx">main</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;fmt&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;io/ioutil&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;os&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;gopkg.in/russross/blackfriday.v2&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">md</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">ioutil</span><span class="p">.</span><span class="nf">ReadFile</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nx">Args</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">fmt</span><span class="p">.</span><span class="nf">Fprintln</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nx">Stderr</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="cp">//HTMLFlags and Renderer</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">htmlFlags</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">CommonHTMLFlags</span><span class="w"> </span><span class="cp">//UseXHTML | Smartypants | SmartypantsFractions | SmartypantsDashes | SmartypantsLatexDashes</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">htmlFlags</span><span class="w"> </span><span class="o">|=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">FootnoteReturnLinks</span><span class="w"> </span><span class="cp">//Generate a link at the end of a footnote to return to the source</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">htmlFlags</span><span class="w"> </span><span class="o">|=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">SmartypantsAngledQuotes</span><span class="w"> </span><span class="cp">//Enable angled double quotes (with Smartypants) for double quotes rendering</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">htmlFlags</span><span class="w"> </span><span class="o">|=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">SmartypantsQuotesNBSP</span><span class="w"> </span><span class="cp">//Enable French guillemets 損 (with Smartypants)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">renderer</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nf">NewHTMLRenderer</span><span class="p">(</span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">HTMLRendererParameters</span><span class="p">{</span><span class="nx">Flags</span><span class="p">:</span><span class="w"> </span><span class="nx">htmlFlags</span><span class="p">,</span><span class="w"> </span><span class="nx">Title</span><span class="p">:</span><span class="w"> </span><span class="s">&#34;&#34;</span><span class="p">,</span><span class="w"> </span><span class="nx">CSS</span><span class="p">:</span><span class="w"> </span><span class="s">&#34;&#34;</span><span class="p">})</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="cp">//Extensions</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">extFlags</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">CommonExtensions</span><span class="w"> </span><span class="cp">//NoIntraEmphasis | Tables | FencedCode | Autolink | Strikethrough | SpaceHeadings | HeadingIDs | BackslashLineBreak | DefinitionLists</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">extFlags</span><span class="w"> </span><span class="o">|=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">Footnotes</span><span class="w"> </span><span class="cp">//Pandoc-style footnotes</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">extFlags</span><span class="w"> </span><span class="o">|=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">HeadingIDs</span><span class="w"> </span><span class="cp">//specify heading IDs with {#id}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">extFlags</span><span class="w"> </span><span class="o">|=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">Titleblock</span><span class="w"> </span><span class="cp">//Titleblock ala pandoc</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">extFlags</span><span class="w"> </span><span class="o">|=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nx">DefinitionLists</span><span class="w"> </span><span class="cp">//Render definition lists</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">html</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nf">Run</span><span class="p">(</span><span class="nx">md</span><span class="p">,</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nf">WithExtensions</span><span class="p">(</span><span class="nx">extFlags</span><span class="p">),</span><span class="w"> </span><span class="nx">blackfriday</span><span class="p">.</span><span class="nf">WithRenderer</span><span class="p">(</span><span class="nx">renderer</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nb">string</span><span class="p">(</span><span class="nx">html</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p><a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go"><code>blackfriday</code></a><code>.WithExtensions()</code> 関数および <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go"><code>blackfriday</code></a><code>.WithRenderer()</code> 関数は <a href="https://text.baldanders.info/golang/functional-options-pattern/" target="_blank" title="インスタンスの生成と Functional Options パターン">Functional Options パターン</a>の応用で任意に設定できる。</p> <p>v1.x 系に比べて HTML レンダリング・オプションの指定が面倒くさい感じになっているが，これは <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go"><code>blackfriday</code></a><code>.Renderer</code> インタフェースに合わせた別のレンダリング・パッケージを使えるようにするためらしい。 HTML 変換以外のレンダリング・パッケージとしては $\mathrm{\LaTeX}$ への変換パッケージがあるようだ。</p> <ul> <li><a href="https://github.com/Ambrevar/blackfriday-latex" target="_blank">Ambrevar/blackfriday-latex: A LaTeX renderer for the Blackfriday Markdown Processor</a></li> </ul> <p>数式表現はできれば <a href="https://www.mathjax.org/" target="_blank" title="MathJax | Beautiful math in all browsers.">MathJax</a> 互換にしてほしかったが，まぁいいか。 これもそのうち試してみたい。</p> <h2>調子に乗ってプレビュー・ツールを作ってみた</h2> <ul> <li><a href="https://github.com/spiegel-im-spiegel/markdown-preview" target="_blank">spiegel-im-spiegel/markdown-preview: Markdown Preview Tool</a></li> </ul> <p>一応<a href="https://github.com/spiegel-im-spiegel/markdown-preview/releases/latest" target="_blank">バイナリも用意</a>している。 使い方はこんな感じ。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ markdown-preview -h </span></span><span class="line"><span class="cl">Processing Markdown by Golang </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Usage: </span></span><span class="line"><span class="cl"> markdown-preview [flags] </span></span><span class="line"><span class="cl"> markdown-preview [command] </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Available Commands: </span></span><span class="line"><span class="cl"> help Help about any command </span></span><span class="line"><span class="cl"> proc Processing Markdown </span></span><span class="line"><span class="cl"> version Print the version number of markdown-preview </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Flags: </span></span><span class="line"><span class="cl"> -h, --help help for markdown-preview </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Use &#34;markdown-preview [command] --help&#34; for more information about a command. </span></span></code></pre></div><p>今のところは HTML への変換のみサポートしている。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ markdown-preview proc -h </span></span><span class="line"><span class="cl">Processing Markdown </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Usage: </span></span><span class="line"><span class="cl"> markdown-preview proc [flags] [markdown file] </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Flags: </span></span><span class="line"><span class="cl"> -c, --css string CSS file URL (with --page option) </span></span><span class="line"><span class="cl"> -g, --github use GitHub Markdown API </span></span><span class="line"><span class="cl"> -h, --help help for proc </span></span><span class="line"><span class="cl"> -l, --line-break translate newlines into line breaks </span></span><span class="line"><span class="cl"> -o, --output string output file path </span></span><span class="line"><span class="cl"> -p, --page generate a complete HTML page </span></span><span class="line"><span class="cl"> -s, --sanitize sanitize untrusted content </span></span></code></pre></div><h3><a href="https://github.com/" target="_blank">GitHub</a> Markdown API</h3> <p><code>--github</code> オプションを使うと <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">blackfriday</a> パッケージではなく <a href="https://github.com/" target="_blank">GitHub</a> Markdown API を使う。</p> <ul> <li><a href="https://developer.github.com/v3/markdown/" target="_blank">Markdown | GitHub Developer Guide</a></li> </ul> <p><a href="https://github.com/" target="_blank">GitHub</a> Markdown API を利用するには Google による <a href="https://github.com/google/go-github" target="_blank" title="google/go-github: Go library for accessing the GitHub API">go-github</a>/github パッケージが便利である。 こんな感じに書ける。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;context&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;github.com/google/go-github/github&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">renderWithGitHub</span><span class="p">(</span><span class="nx">md</span><span class="w"> </span><span class="p">[]</span><span class="kt">byte</span><span class="p">)</span><span class="w"> </span><span class="p">([]</span><span class="kt">byte</span><span class="p">,</span><span class="w"> </span><span class="kt">error</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">client</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">github</span><span class="p">.</span><span class="nf">NewClient</span><span class="p">(</span><span class="kc">nil</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">opt</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="o">&amp;</span><span class="nx">github</span><span class="p">.</span><span class="nx">MarkdownOptions</span><span class="p">{</span><span class="nx">Mode</span><span class="p">:</span><span class="w"> </span><span class="s">&#34;gfm&#34;</span><span class="p">,</span><span class="w"> </span><span class="nx">Context</span><span class="p">:</span><span class="w"> </span><span class="s">&#34;google/go-github&#34;</span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">body</span><span class="p">,</span><span class="w"> </span><span class="nx">_</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">client</span><span class="p">.</span><span class="nf">Markdown</span><span class="p">(</span><span class="nx">context</span><span class="p">.</span><span class="nf">Background</span><span class="p">(),</span><span class="w"> </span><span class="nb">string</span><span class="p">(</span><span class="nx">md</span><span class="p">),</span><span class="w"> </span><span class="nx">opt</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="p">[]</span><span class="nb">byte</span><span class="p">(</span><span class="nx">body</span><span class="p">),</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><h3>テンプレートを使ったページの出力</h3> <p><code>--page</code> オプションを使うと完全なページを出力する。 <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">blackfriday</a> パッケージなら <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go"><code>blackfriday</code></a><code>.CompletePage</code> フラグを付加することで完全なページを出力してくれるが，今回はテンプレートを使ってページを出力するようにした。</p> <p><a href="https://golang.org/" target="_blank" title="The Go Programming Language">Go 言語</a>標準のテンプレートパッケージには <a href="https://golang.org/pkg/text/template/" target="_blank" title="template - The Go Programming Language"><code>text/template</code></a> と <a href="https://golang.org/pkg/html/template/" target="_blank" title="template - The Go Programming Language"><code>html/template</code></a> の2つがある。 <a href="https://golang.org/pkg/html/template/" target="_blank" title="template - The Go Programming Language"><code>html/template</code></a> は <code>&lt;</code> や <code>&gt;</code> などの特殊文字を適切に変換してくれるので良いのだが，今回は HTML テキストをまるっと埋め込むので（勝手に sanitizing されては困るので） <a href="https://golang.org/pkg/text/template/" target="_blank" title="template - The Go Programming Language"><code>text/template</code></a> のほうを使うことにした。</p> <p>また，テンプレートファイルは <a href="https://text.baldanders.info/golang/using-go-assets/" target="_blank" title="go-assets でシングルバイナリにまとめる">go-assets を使って</a>コードに埋め込むことにした。 いやぁ，<a href="https://text.baldanders.info/golang/using-go-assets/" target="_blank" title="go-assets でシングルバイナリにまとめる">勉強して</a>おいてよかった。</p> <p>用意したテンプレートファイルはこんな感じ。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="cp">&lt;!DOCTYPE html&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">html</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">head</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">meta</span> <span class="na">charset</span><span class="o">=</span><span class="s">&#34;utf-8&#34;</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">meta</span> <span class="na">name</span><span class="o">=</span><span class="s">&#34;viewport&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;width=device-width, initial-scale=1&#34;</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">meta</span> <span class="na">name</span><span class="o">=</span><span class="s">&#34;generator&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;markdown-preview&#34;</span><span class="p">&gt;</span>{{with .CSS }} </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">link</span> <span class="na">rel</span><span class="o">=</span><span class="s">&#34;stylesheet&#34;</span> <span class="na">type</span><span class="o">=</span><span class="s">&#34;text/css&#34;</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;{{ . }}&#34;</span><span class="p">&gt;</span>{{ end }} </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">title</span><span class="p">&gt;</span>{{ .Title }}<span class="p">&lt;/</span><span class="nt">title</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">head</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">body</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">{{ .Body }} </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">body</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">html</span><span class="p">&gt;</span> </span></span></code></pre></div><p><a href="https://gohugo.io/" target="_blank" title="The world’s fastest framework for building websites | Hugo">Hugo</a> でテンプレートの扱いにはすっかり慣れてしまったので，このくらいは楽勝である（笑）</p> <p>テンプレートに埋め込むためのデータセットはこんな感じで用意した。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kd">type</span><span class="w"> </span><span class="nx">PageData</span><span class="w"> </span><span class="kd">struct</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">Title</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">CSS</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">Body</span><span class="w"> </span><span class="kt">string</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p>これで，テンプレート処理は以下のように書ける。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="cp">//Render returns HTML page text with template</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="p">(</span><span class="nx">p</span><span class="w"> </span><span class="o">*</span><span class="nx">PageData</span><span class="p">)</span><span class="w"> </span><span class="nf">Render</span><span class="p">()</span><span class="w"> </span><span class="p">([]</span><span class="kt">byte</span><span class="p">,</span><span class="w"> </span><span class="kt">error</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">f</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">data</span><span class="p">.</span><span class="nx">Assets</span><span class="p">.</span><span class="nf">Open</span><span class="p">(</span><span class="s">&#34;/template.html&#34;</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="kc">nil</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">tmpData</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="o">&amp;</span><span class="nx">bytes</span><span class="p">.</span><span class="nx">Buffer</span><span class="p">{}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">io</span><span class="p">.</span><span class="nf">Copy</span><span class="p">(</span><span class="nx">tmpData</span><span class="p">,</span><span class="w"> </span><span class="nx">f</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">t</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">template</span><span class="p">.</span><span class="nf">New</span><span class="p">(</span><span class="s">&#34;Markdown Processing&#34;</span><span class="p">).</span><span class="nf">Parse</span><span class="p">(</span><span class="nx">tmpData</span><span class="p">.</span><span class="nf">String</span><span class="p">())</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="kc">nil</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">buf</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="o">&amp;</span><span class="nx">bytes</span><span class="p">.</span><span class="nx">Buffer</span><span class="p">{}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="nx">t</span><span class="p">.</span><span class="nf">Execute</span><span class="p">(</span><span class="nx">buf</span><span class="p">,</span><span class="w"> </span><span class="nx">p</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="nx">buf</span><span class="p">.</span><span class="nf">Bytes</span><span class="p">(),</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><h3>今後の予定</h3> <p>というほどではないが，簡易 Web サービスでプレビューできるようにしたいな，と。 <a href="https://github.com/mattn/mkup" target="_blank" title="mattn/mkup: Portable Markdown Previewer">mattn/mkup</a> みたいな感じ。 ただ <a href="https://golang.org/" target="_blank" title="The Go Programming Language">Go 言語</a>による Web アプリケーションは最近勉強を始めたばかりなので当分先だろうけど（その前に <a href="https://github.com/spiegel-im-spiegel/gpgpdump" target="_blank" title="spiegel-im-spiegel/gpgpdump: OpenPGP packet visualizer">gpgpdump</a> の <a href="https://datatracker.ietf.org/doc/draft-ietf-openpgp-rfc4880bis/" target="_blank" title="draft-ietf-openpgp-rfc4880bis - OpenPGP Message Format">RFC 4880bis</a> 対応しろって）。</p> <p>個人的に CLI のフィルタ・コマンド大好きなので，そういうものばっかり（主に自分用に）作ってるが，監視系のツールや繰り返し処理が多いものについては簡易 Web サービスを立ててブラウザ上で作業するのもアリなんじゃないかと思ったりしている。</p> <h2>ブックマーク</h2> <ul> <li> <p><a href="https://inside.dmm.com/entry/2018/05/28/golang-cli-tool" target="_blank">Go言語初学者がConfluenceをMarkdownで書くためのCLIツールを開発した話 - DMM inside</a> : Markdown 記法から Wiki 記法への変換</p> </li> <li> <p><a href="https://text.baldanders.info/golang/consider-switching-from-glide-to-dep/" target="_blank">Glide から Dep への移行を検討する</a></p> </li> </ul> tag:text.Baldanders.info,2018-02-15:/remark/2018/02/from-markdown-to-html/ 2018-02-15T13:40:48+00:00 2019-07-01T13:48:09+00:00

どうせならビルドも導入も簡単な Go 言語製のツールがいいな，と思ってたのだが，結構あってビックリした。

Spiegel https://baldanders.info/profile/ <p>Markdown テキストを HTML 等の他のドキュメント形式に変換するツールは色々あるけれど<sup id="fnref:1"><a href="#fn:1" class="footnote-ref" role="doc-noteref">1</a></sup>，今のところは大げさなドキュメントフレームワークを組むつもりは全くなくて（このサイトで使ってる <a href="https://gohugo.io/" target="_blank" title="The world’s fastest framework for building websites | Hugo">Hugo</a> で必要十分だし）「もっとカジュアルに変換できるツールがないかなぁ」とググってみたのですよ。 どうせならビルドも導入も簡単な <a href="https://golang.org/" target="_blank" title="The Go Programming Language">Go 言語</a>製のツールがいいな，と思ってたのだが，結構あってビックリした。 まぁみんな同じようなことを考えてるってことかねぇ。</p> <h2><a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">russross/blackfriday</a></h2> <p>まずは <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">russross/blackfriday</a>。</p> <p>名前はアレだけど，割とちゃんとしたパーサみたい<sup id="fnref:2"><a href="#fn:2" class="footnote-ref" role="doc-noteref">2</a></sup>。 同じ作者によるコマンドライン・ツール <a href="https://github.com/russross/blackfriday-tool" target="_blank" title="russross/blackfriday-tool: Blackfriday command-line tool">russross/blackfriday-tool</a> も提供されているのですぐ使える。</p> <p><a href="https://github.com/russross/blackfriday-tool" target="_blank" title="russross/blackfriday-tool: Blackfriday command-line tool">russross/blackfriday-tool</a> はバイナリ提供はされてないようなので（つか <code>main.go</code> ひとつだけだし<code>w</code>），素直に <code>go get</code> コマンドでインストールする。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ go get -v github.com/russross/blackfriday-tool </span></span></code></pre></div><p>ヘルプを見るとこんな感じ。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ blackfriday-tool -h </span></span><span class="line"><span class="cl">Blackfriday Markdown Processor v1.5 </span></span><span class="line"><span class="cl">Available at http://github.com/russross/blackfriday </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Copyright © 2011 Russ Ross &lt;russ@russross.com&gt; </span></span><span class="line"><span class="cl">Distributed under the Simplified BSD License </span></span><span class="line"><span class="cl">See website for details </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Usage: </span></span><span class="line"><span class="cl"> blackfriday-tool [options] [inputfile [outputfile]] </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">Options: </span></span><span class="line"><span class="cl"> -cpuprofile string </span></span><span class="line"><span class="cl"> Write cpu profile to a file </span></span><span class="line"><span class="cl"> -css string </span></span><span class="line"><span class="cl"> Link to a CSS stylesheet (implies -page) </span></span><span class="line"><span class="cl"> -fractions </span></span><span class="line"><span class="cl"> Use improved fraction rules for smartypants (default true) </span></span><span class="line"><span class="cl"> -latex </span></span><span class="line"><span class="cl"> Generate LaTeX output instead of HTML </span></span><span class="line"><span class="cl"> -latexdashes </span></span><span class="line"><span class="cl"> Use LaTeX-style dash rules for smartypants (default true) </span></span><span class="line"><span class="cl"> -page </span></span><span class="line"><span class="cl"> Generate a standalone HTML page (implies -latex=false) </span></span><span class="line"><span class="cl"> -repeat int </span></span><span class="line"><span class="cl"> Process the input multiple times (for benchmarking) (default 1) </span></span><span class="line"><span class="cl"> -smartypants </span></span><span class="line"><span class="cl"> Apply smartypants-style substitutions (default true) </span></span><span class="line"><span class="cl"> -toc </span></span><span class="line"><span class="cl"> Generate a table of contents (implies -latex=false) </span></span><span class="line"><span class="cl"> -toconly </span></span><span class="line"><span class="cl"> Generate a table of contents only (implies -toc) </span></span><span class="line"><span class="cl"> -xhtml </span></span><span class="line"><span class="cl"> Use XHTML-style tags in HTML output (default true) </span></span></code></pre></div><p>入力データは以下のものを用意してみた。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-markdown" data-lang="markdown"><span class="line"><span class="cl"><span class="gh"># Go 1.8.7 および 1.9.4 がリリース </span></span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">[Go 言語]コンパイラの 1.8.7 および 1.9.4 がリリースされている。 </span></span><span class="line"><span class="cl">このバージョンでは脆弱性 [CVE-2018-6574] の修正が行われている。 </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="gu">## 脆弱性の内容 </span></span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="sb">`#cgo`</span> ディレクティブを含む [Go 言語]コードをビルドする際に任意の処理を実行される可能性がある。 </span></span><span class="line"><span class="cl"><span class="k"> </span></span></span><span class="line"><span class="cl"><span class="k">&gt; </span><span class="ge">When cgo is enabled, the build step during “go get” invokes the host C compiler, gcc or clang, adding compiler flags specified in the Go source files. </span></span></span><span class="line"><span class="cl"><span class="k">&gt; </span><span class="ge">Both gcc and clang support a plugin mechanism in which a shared-library plugin is loaded into the compiler, as directed by compiler flags. </span></span></span><span class="line"><span class="cl"><span class="k">&gt; </span><span class="ge">This means that a Go package repository can contain an attack.so file along with a Go source file that says (for example) `// #cgo CFLAGS: -fplugin=attack.so`, causing the attack plugin to be loaded into the host C compiler during the build. </span></span></span><span class="line"><span class="cl"><span class="k">&gt; </span><span class="ge">Gcc and clang plugins are completely unrestricted in their access to the host system. </span></span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="gu">## 影響度（CVSS） </span></span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">「[<span class="nt">CVE-2018-6574 - Red Hat Customer Portal</span>](<span class="na">https://access.redhat.com/security/cve/cve-2018-6574</span>)」より。 </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="gs">**CVSSv3 基本評価値 8.3 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H`)**</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">| 基本評価基準 | 評価値 | </span></span><span class="line"><span class="cl">| ---------------------------------------:|:----------------- | </span></span><span class="line"><span class="cl">| 攻撃元区分（AV） | ネットワーク（N） | </span></span><span class="line"><span class="cl">| 攻撃条件の複雑さ（AC） | 高（H） | </span></span><span class="line"><span class="cl">| 必要な特権レベル（PR） | 不要（N） | </span></span><span class="line"><span class="cl">| ユーザ関与レベル（UI） | 要（R） | </span></span><span class="line"><span class="cl">| スコープ（S） | 変更あり（C） | </span></span><span class="line"><span class="cl">| 情報漏えいの可能性（機密性への影響, C） | 高（H） | </span></span><span class="line"><span class="cl">| 情報改ざんの可能性（完全性への影響, I） | 高（H） | </span></span><span class="line"><span class="cl">| 業務停止の可能性（可用性への影響, A） | 高（H） | </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">CVSS については[<span class="nt">解説ページ</span>](<span class="na">https://text.baldanders.info/remark/2015/cvss-v3-metrics-in-jvn/ &#34;JVN が CVSSv3 による脆弱性評価を開始 — しっぽのさきっちょ | text.Baldanders.info&#34;</span>)を参照のこと。 </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl">[Go 言語]: https://golang.org/ &#34;The Go Programming Language&#34; </span></span><span class="line"><span class="cl">[CVE-2018-6574]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2018-6574 </span></span></code></pre></div><p>これを変換する。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ blackfriday-tool -page -xhtml=false input.md &gt; output.html </span></span></code></pre></div><p>結果はこんな感じになった。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="cp">&lt;!DOCTYPE html&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">html</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">head</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">title</span><span class="p">&gt;</span>Go 1.8.7 および 1.9.4 がリリース<span class="p">&lt;/</span><span class="nt">title</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">meta</span> <span class="na">name</span><span class="o">=</span><span class="s">&#34;GENERATOR&#34;</span> <span class="na">content</span><span class="o">=</span><span class="s">&#34;Blackfriday Markdown Processor v1.5&#34;</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> <span class="p">&lt;</span><span class="nt">meta</span> <span class="na">charset</span><span class="o">=</span><span class="s">&#34;utf-8&#34;</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">head</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">body</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">h1</span><span class="p">&gt;</span>Go 1.8.7 および 1.9.4 がリリース<span class="p">&lt;/</span><span class="nt">h1</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://golang.org/&#34;</span> <span class="na">title</span><span class="o">=</span><span class="s">&#34;The Go Programming Language&#34;</span><span class="p">&gt;</span>Go 言語<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>コンパイラの 1.8.7 および 1.9.4 がリリースされている。 </span></span><span class="line"><span class="cl">このバージョンでは脆弱性 <span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://cve.mitre.org/cgi-bin/cvename.cgi?name=2018-6574&#34;</span><span class="p">&gt;</span>CVE-2018-6574<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span> の修正が行われている。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">h2</span><span class="p">&gt;</span>脆弱性の内容<span class="p">&lt;/</span><span class="nt">h2</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;&lt;</span><span class="nt">code</span><span class="p">&gt;</span>#cgo<span class="p">&lt;/</span><span class="nt">code</span><span class="p">&gt;</span> ディレクティブを含む <span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://golang.org/&#34;</span> <span class="na">title</span><span class="o">=</span><span class="s">&#34;The Go Programming Language&#34;</span><span class="p">&gt;</span>Go 言語<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>コードをビルドする際に任意の処理を実行される可能性がある。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">blockquote</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;</span>When cgo is enabled, the build step during “go get” invokes the host C compiler, gcc or clang, adding compiler flags specified in the Go source files. </span></span><span class="line"><span class="cl">Both gcc and clang support a plugin mechanism in which a shared-library plugin is loaded into the compiler, as directed by compiler flags. </span></span><span class="line"><span class="cl">This means that a Go package repository can contain an attack.so file along with a Go source file that says (for example) <span class="p">&lt;</span><span class="nt">code</span><span class="p">&gt;</span>// #cgo CFLAGS: -fplugin=attack.so<span class="p">&lt;/</span><span class="nt">code</span><span class="p">&gt;</span>, causing the attack plugin to be loaded into the host C compiler during the build. </span></span><span class="line"><span class="cl">Gcc and clang plugins are completely unrestricted in their access to the host system.<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">blockquote</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">h2</span><span class="p">&gt;</span>影響度（CVSS）<span class="p">&lt;/</span><span class="nt">h2</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;</span>「<span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://access.redhat.com/security/cve/cve-2018-6574&#34;</span><span class="p">&gt;</span>CVE-2018-6574 - Red Hat Customer Portal<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>」より。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;&lt;</span><span class="nt">strong</span><span class="p">&gt;</span>CVSSv3 基本評価値 8.3 (<span class="p">&lt;</span><span class="nt">code</span><span class="p">&gt;</span>CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H<span class="p">&lt;/</span><span class="nt">code</span><span class="p">&gt;</span>)<span class="p">&lt;/</span><span class="nt">strong</span><span class="p">&gt;&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">table</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">thead</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">th</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>基本評価基準<span class="p">&lt;/</span><span class="nt">th</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">th</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>評価値<span class="p">&lt;/</span><span class="nt">th</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">thead</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tbody</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>攻撃元区分（AV）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>ネットワーク（N）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>攻撃条件の複雑さ（AC）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>必要な特権レベル（PR）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>不要（N）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>ユーザ関与レベル（UI）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>要（R）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>スコープ（S）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>変更あり（C）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>情報漏えいの可能性（機密性への影響, C）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>情報改ざんの可能性（完全性への影響, I）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>業務停止の可能性（可用性への影響, A）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tbody</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">table</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;</span>CVSS については<span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://text.baldanders.info/remark/2015/cvss-v3-metrics-in-jvn/&#34;</span> <span class="na">title</span><span class="o">=</span><span class="s">&#34;JVN が CVSSv3 による脆弱性評価を開始 — しっぽのさきっちょ | text.Baldanders.info&#34;</span><span class="p">&gt;</span>解説ページ<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>を参照のこと。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">body</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">html</span><span class="p">&gt;</span> </span></span></code></pre></div><p>まぁ，概ね良い感じではないだろうか。 ちなみに <code>-css</code> オプションで CSS ファイルへのパスを指定できるのでレイアウトについては多少調整できるだろう。</p> <p><a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">russross/blackfriday</a> は v2 が最新版でかなり頻繁にメンテナンスされているようだが， <a href="https://github.com/" target="_blank">GitHub</a> リポジトリの master ブランチは v1 系なので注意が必要である。 そのうち弄って遊びたい。</p> <h2><a href="https://github.com/" target="_blank">GitHub</a> の Markdown API を利用する。</h2> <p><a href="https://github.com/" target="_blank">GitHub</a> が Markdown 変換用の REST API を提供しているらしい。</p> <ul> <li><a href="https://developer.github.com/v3/markdown/" target="_blank">Markdown | GitHub Developer Guide</a></li> </ul> <p>更にこの API を利用するためのパッケージを Google が提供している。</p> <ul> <li><a href="https://github.com/google/go-github" target="_blank">google/go-github: Go library for accessing the GitHub API</a></li> </ul> <p>では，このパッケージを使った変換コードを書いてみよう。 こんな感じかな。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go"><span class="line"><span class="cl"><span class="kn">package</span><span class="w"> </span><span class="nx">main</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kn">import</span><span class="w"> </span><span class="p">(</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;fmt&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;io&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;io/ioutil&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;os&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;strings&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="s">&#34;github.com/google/go-github/github&#34;</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="kd">func</span><span class="w"> </span><span class="nf">main</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">md</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">ioutil</span><span class="p">.</span><span class="nf">ReadFile</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nx">Args</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">fmt</span><span class="p">.</span><span class="nf">Fprintln</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nx">Stderr</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">client</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">github</span><span class="p">.</span><span class="nf">NewClient</span><span class="p">(</span><span class="kc">nil</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">opt</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="o">&amp;</span><span class="nx">github</span><span class="p">.</span><span class="nx">MarkdownOptions</span><span class="p">{</span><span class="nx">Mode</span><span class="p">:</span><span class="w"> </span><span class="s">&#34;gfm&#34;</span><span class="p">,</span><span class="w"> </span><span class="nx">Context</span><span class="p">:</span><span class="w"> </span><span class="s">&#34;google/go-github&#34;</span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">html</span><span class="p">,</span><span class="w"> </span><span class="nx">_</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="nx">client</span><span class="p">.</span><span class="nf">Markdown</span><span class="p">(</span><span class="nb">string</span><span class="p">(</span><span class="nx">md</span><span class="p">),</span><span class="w"> </span><span class="nx">opt</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="p">{</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">fmt</span><span class="p">.</span><span class="nf">Fprintln</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nx">Stderr</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="p">)</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="k">return</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="p">}</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="w"> </span><span class="nx">io</span><span class="p">.</span><span class="nf">Copy</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nx">Stdout</span><span class="p">,</span><span class="w"> </span><span class="nx">strings</span><span class="p">.</span><span class="nf">NewReader</span><span class="p">(</span><span class="nx">html</span><span class="p">))</span><span class="w"> </span></span></span><span class="line"><span class="cl"><span class="p">}</span><span class="w"> </span></span></span></code></pre></div><p>実際に動かしてみる。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ go run githubapi.go input.md &gt; output2.html </span></span></code></pre></div><p>出力はこんな感じになった。</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-html" data-lang="html"><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">h1</span><span class="p">&gt;</span>Go 1.8.7 および 1.9.4 がリリース<span class="p">&lt;/</span><span class="nt">h1</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://golang.org/&#34;</span> <span class="na">title</span><span class="o">=</span><span class="s">&#34;The Go Programming Language&#34;</span> <span class="na">rel</span><span class="o">=</span><span class="s">&#34;nofollow&#34;</span><span class="p">&gt;</span>Go 言語<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>コンパイラの 1.8.7 および 1.9.4 がリリースされている。<span class="p">&lt;</span><span class="nt">br</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl">このバージョンでは脆弱性 <span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://cve.mitre.org/cgi-bin/cvename.cgi?name=2018-6574&#34;</span> <span class="na">rel</span><span class="o">=</span><span class="s">&#34;nofollow&#34;</span><span class="p">&gt;</span>CVE-2018-6574<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span> の修正が行われている。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">h2</span><span class="p">&gt;</span>脆弱性の内容<span class="p">&lt;/</span><span class="nt">h2</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;&lt;</span><span class="nt">code</span><span class="p">&gt;</span>#cgo<span class="p">&lt;/</span><span class="nt">code</span><span class="p">&gt;</span> ディレクティブを含む <span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://golang.org/&#34;</span> <span class="na">title</span><span class="o">=</span><span class="s">&#34;The Go Programming Language&#34;</span> <span class="na">rel</span><span class="o">=</span><span class="s">&#34;nofollow&#34;</span><span class="p">&gt;</span>Go 言語<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>コードをビルドする際に任意の処理を実行される可能性がある。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">blockquote</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;</span>When cgo is enabled, the build step during “go get” invokes the host C compiler, gcc or clang, adding compiler flags specified in the Go source files.<span class="p">&lt;</span><span class="nt">br</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl">Both gcc and clang support a plugin mechanism in which a shared-library plugin is loaded into the compiler, as directed by compiler flags.<span class="p">&lt;</span><span class="nt">br</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl">This means that a Go package repository can contain an attack.so file along with a Go source file that says (for example) <span class="p">&lt;</span><span class="nt">code</span><span class="p">&gt;</span>// #cgo CFLAGS: -fplugin=attack.so<span class="p">&lt;/</span><span class="nt">code</span><span class="p">&gt;</span>, causing the attack plugin to be loaded into the host C compiler during the build.<span class="p">&lt;</span><span class="nt">br</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl">Gcc and clang plugins are completely unrestricted in their access to the host system.<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">blockquote</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">h2</span><span class="p">&gt;</span>影響度（CVSS）<span class="p">&lt;/</span><span class="nt">h2</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;</span>「<span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://access.redhat.com/security/cve/cve-2018-6574&#34;</span> <span class="na">rel</span><span class="o">=</span><span class="s">&#34;nofollow&#34;</span><span class="p">&gt;</span>CVE-2018-6574 - Red Hat Customer Portal<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>」より。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;&lt;</span><span class="nt">strong</span><span class="p">&gt;</span>CVSSv3 基本評価値 8.3 (<span class="p">&lt;</span><span class="nt">code</span><span class="p">&gt;</span>CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H<span class="p">&lt;/</span><span class="nt">code</span><span class="p">&gt;</span>)<span class="p">&lt;/</span><span class="nt">strong</span><span class="p">&gt;&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">table</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">thead</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">th</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>基本評価基準<span class="p">&lt;/</span><span class="nt">th</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">th</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>評価値<span class="p">&lt;/</span><span class="nt">th</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">thead</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tbody</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>攻撃元区分（AV）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>ネットワーク（N）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>攻撃条件の複雑さ（AC）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>必要な特権レベル（PR）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>不要（N）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>ユーザ関与レベル（UI）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>要（R）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>スコープ（S）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>変更あり（C）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>情報漏えいの可能性（機密性への影響, C）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>情報改ざんの可能性（完全性への影響, I）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">tr</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;right&#34;</span><span class="p">&gt;</span>業務停止の可能性（可用性への影響, A）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">td</span> <span class="na">align</span><span class="o">=</span><span class="s">&#34;left&#34;</span><span class="p">&gt;</span>高（H）<span class="p">&lt;/</span><span class="nt">td</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;/</span><span class="nt">tr</span><span class="p">&gt;&lt;/</span><span class="nt">tbody</span><span class="p">&gt;&lt;/</span><span class="nt">table</span><span class="p">&gt;</span> </span></span><span class="line"><span class="cl"><span class="p">&lt;</span><span class="nt">p</span><span class="p">&gt;</span>CVSS については<span class="p">&lt;</span><span class="nt">a</span> <span class="na">href</span><span class="o">=</span><span class="s">&#34;https://text.baldanders.info/remark/2015/cvss-v3-metrics-in-jvn/&#34;</span> <span class="na">title</span><span class="o">=</span><span class="s">&#34;JVN が CVSSv3 による脆弱性評価を開始 — しっぽのさきっちょ | text.Baldanders.info&#34;</span> <span class="na">rel</span><span class="o">=</span><span class="s">&#34;nofollow&#34;</span><span class="p">&gt;</span>解説ページ<span class="p">&lt;/</span><span class="nt">a</span><span class="p">&gt;</span>を参照のこと。<span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span> </span></span></code></pre></div><p>出力されるのは <code>&lt;body&gt;</code> 要素内の部分のみなので，ページとして体裁を整えるには別途 <code>&lt;head&gt;</code> 要素などを補う必要がある。</p> <p>それにしても <code>&lt;th&gt;</code> 要素や <code>&lt;td&gt;</code> 要素内の <code>align</code> 属性をいい加減なんとかしてくれないものだろうか。 これ <a href="https://validator.w3.org/" target="_blank" title="The W3C Markup Validation Service">Validator</a> にものごっつ怒られるんだよね。</p> <h2>プレビュー用簡易 Web サーバ・ツール</h2> <p>最後は，変換ツールとはちょっと違うけど，プレビュー用簡易 Web サーバ・ツールを紹介する。</p> <ul> <li><a href="https://github.com/mattn/mkup" target="_blank">mattn/mkup: Portable Markdown Previewer</a></li> </ul> <p><a href="https://github.com/mattn/mkup/releases/latest" target="_blank">リリースページ</a>にバイナリが置いてあるので，ありがたく使わせていただく。 先程の <code>input.md</code> が置いてあるフォルダで</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">$ mkup </span></span><span class="line"><span class="cl">Lisning at :8000 </span></span></code></pre></div><p>と起動する。 この状態で <code>http://localhost:8000/input.md</code> にアクセスすれば HTML 変換された内容が表示される。 パーサは <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">russross/blackfriday</a> を使っているようだ。 ファイルの内容を変更すれば自動的にリロードしてくれる。</p> <p>例えば，このブログの記事は markdown で入力してるけど， <a href="https://gohugo.io/" target="_blank" title="The world’s fastest framework for building websites | Hugo">Hugo</a> のサーバ・モードでリアルタイムに確認しながら作業できるのがとても便利である。 そういう意味で簡易サーバ型のプレビュー・ツールは使い勝手がいいと思う。</p> <h2>ブックマーク</h2> <ul> <li><a href="http://hiropo.co.uk/archives/985.html" target="_blank">ひろぽっぽれす - いくらが大好きです。Webの開発やってます - GolangでBlackfridayを使ってMarkdownをHTMLに変換する</a></li> <li><a href="https://ja.louisaandlily.com/markdown-to-html-with-golang" target="_blank">Markdown記法で書かれたものをHTMLに変換するGo言語コード</a></li> <li><a href="https://m0t0k1ch1st0ry.com/blog/2014/06/03/github-api/" target="_blank">Golang で GitHub の Markdown API をたたく · m0t0k1ch1st0ry</a></li> <li><a href="https://mattn.kaoriya.net/software/lang/go/20150703125421.htm" target="_blank">Big Sky :: markdown を何時でもチャラーっとプレビューしたい。</a></li> </ul> <!-- eof --> <div class="footnotes" role="doc-endnotes"> <hr> <ol> <li id="fn:1"> <p>オリジナルの markdown パーサって Perl だったっけ？ うろ覚えだけど。以前に <a href="https://qiita.com/spiegel-im-spiegel/items/cdea4a17b44fb59d6320" target="_blank" title="Markdown ファイルを PDF に変換する。 - Qiita">node.js 上で markdown から PDF に変換する方法は調べた</a>けどスクリプト言語は環境を整えるのが面倒なのとモジュール間の依存関係が煩わしいのであまり使いたくない。仕事ならやるけど。とりあえず HTML 形式に変換しておけば，あとは LaTeX でも PDF でもどうとでもなるし，そもそも今回はそこまでやる気はない。&#160;<a href="#fnref:1" class="footnote-backref" role="doc-backlink">&#x21a9;&#xfe0e;</a></p> </li> <li id="fn:2"> <p>このブログでも利用している <a href="https://gohugo.io/" target="_blank" title="The world’s fastest framework for building websites | Hugo">Hugo</a> も markdown パーサとして <a href="https://github.com/russross/blackfriday" target="_blank" title="russross/blackfriday: Blackfriday: a markdown processor for Go">russross/blackfriday</a> を使っているようである。&#160;<a href="#fnref:2" class="footnote-backref" role="doc-backlink">&#x21a9;&#xfe0e;</a></p> </li> </ol> </div>