Web ページのメタデータを取得する webinfo/webinfo をリリースした

package main

import (
    "bytes"
    "context"
    "encoding/json"
    "fmt"
    "io"
    "os"

    "github.com/goark/webinfo"
)

func errorOut(err error) {
    fmt.Fprintf(os.Stderr, "%+v\n", err)
}

func main() {
    ctx := context.Background()
    // Fetch metadata for a page
    info, err := webinfo.Fetch(ctx, "https://text.baldanders.info/", "") // empty UA uses default
    if err != nil {
        errorOut(err)
        return
    }
    // output metadata as pretty JSON
    b, err := json.MarshalIndent(info, "", "  ")
    if err != nil {
        errorOut(err)
        return
    }
    if _, err := io.Copy(os.Stdout, bytes.NewBuffer(b)); err != nil {
        errorOut(err)
        return
    }
    fmt.Println()
    fmt.Println()

    // Download main image to permanent file in current directory
    imgPath, err := info.DownloadImage(ctx, ".", false)
    if err != nil {
        errorOut(err)
        return
    }
    fmt.Println("image saved:", imgPath)

    // Download thumbnail to permanent file in current directory
    thumbPath, err := info.DownloadThumbnail(ctx, ".", 150, false) // 150px width
    if err != nil {
        errorOut(err)
        return
    }
    fmt.Println("thumbnail saved:", thumbPath)
}

$ go run sample.go
{
  "url": "https://text.baldanders.info/",
  "location": "https://text.baldanders.info/",
  "canonical": "https://text.baldanders.info/",
  "title": "text.Baldanders.info",
  "description": "帰ってきた「しっぽのさきっちょ」",
  "image_url": "https://text.baldanders.info/images/attention/site.jpg",
  "user_agent": "Mozilla/5.0 (Windows NT 6.1; rv:11.0) Gecko/20100101 Firefox/11.0"
}

image saved: site.jpg
thumbnail saved: site-thumb.jpg