[Go] Download Youtube

程式語言：Go
Package：
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/url"
"os"
"path/filepath"
"regexp"
"strings"
GitHub 網址

功能：下載 youtube 影片

工作原理

  • api
    • http://www.youtube.com/get_video_info?video_id=v
      • 得到影片相關資訊
      • 範例
        • 影片網址：https://www.youtube.com/watch?v=5yAU52qfYuU
          查詢網址：http://www.youtube.com/get_video_info?video_id=5yAU52qfYuU
      • 回傳資料
        • 格式 Query String
        • 重要參數
          • length_seconds 影片長度
          • author 作者
          • thumbnail_url 封面縮圖
          • title 標題
          • view_count 觀看次數
          • url_encoded_fmt_stream_map 不同品質影片的來源資訊
            • 格式 Query String
            • 資料
              • quality 品質
              • type 影片格式
              • url 網址

程式碼 

  1. package gotube
  2.  
  3. import (
  4.     "fmt"
  5.     "io"
  6.     "io/ioutil"
  7.     "log"
  8.     "net/http"
  9.     "net/url"
  10.     "os"
  11.     "path/filepath"
  12.     "regexp"
  13.     "strings"
  14. )
  15.  
  16. const userAgent = `Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0`
  17.  
  18. type Youtube struct {
  19.     videoID  string
  20.     VideoURL string
  21.     VideoInfo
  22. }
  23.  
  24. type VideoInfo struct {
  25.     URL     string
  26.     Quality string
  27.     Ext     string
  28.     Name    string
  29. }
  30.  
  31. func (y *Youtube) api(method string) ([]byte, error) {
  32.     urlIndex := "http://www.youtube.com/" + method
  33.     req, err := http.NewRequest(http.MethodGet, urlIndex, nil)
  34.     if err != nil {
  35.         return nil, err
  36.     }
  37.     req.Header.Add("User-Agent", userAgent)
  38.  
  39.     q := req.URL.Query()
  40.     q.Add("video_id", y.videoID)
  41.     req.URL.RawQuery = q.Encode()
  42.     log.Printf("Request api url=%s", req.URL)
  43.  
  44.     client := &http.Client{}
  45.     resp, err := client.Do(req)
  46.     if err != nil {
  47.         return nil, err
  48.     }
  49.     defer resp.Body.Close()
  50.  
  51.     body, err := ioutil.ReadAll(resp.Body)
  52.     if err != nil {
  53.         return nil, err
  54.     }
  55.  
  56.     return body, nil
  57. }
  58.  
  59. func (y *Youtube) getVideoInfo() error {
  60.     body, err := y.api("get_video_info")
  61.  
  62.     m, err := url.ParseQuery(string(body))
  63.     if err != nil {
  64.         return err
  65.     }
  66.  
  67.     y.VideoInfo.Name = m.Get("title")
  68.  
  69.     qs := m.Get("url_encoded_fmt_stream_map")
  70.     qs = strings.Replace(qs, ",", "&", -1)
  71.     values, err := url.ParseQuery(qs)
  72.     if err != nil {
  73.         return err
  74.     }
  75.  
  76.     y.VideoInfo.Quality = values.Get("quality")
  77.     y.VideoInfo.URL = values.Get("url")
  78.     ext := strings.Split(values.Get("type"), ";")
  79.     ext = strings.Split(ext[0], "/")
  80.     y.VideoInfo.Ext = ext[1]
  81.  
  82.     log.Printf("Video: %+v\n", y.VideoInfo)
  83.     return nil
  84. }
  85.  
  86. func (y *Youtube) GetVideo() error {
  87.     parse := strings.Split(y.VideoURL, "?")
  88.     paras, err := url.ParseQuery(parse[1])
  89.     if err != nil {
  90.         return err
  91.     }
  92.  
  93.     y.videoID = paras.Get("v")
  94.     err = y.getVideoInfo()
  95.     if err != nil {
  96.         return err
  97.     }
  98.  
  99.     fileName := fmt.Sprintf("%s.%s", FileNameCorrect(y.Name), y.Ext)
  100.     path := filepath.Join(".", fileName)
  101.     if err := DownloadFile(path, y.URL); err != nil {
  102.         return err
  103.     }
  104.  
  105.     return nil
  106. }
  107.  
  108. func FileNameCorrect(s string) string {
  109.     var re = regexp.MustCompile(`[\/:*?"<>|]`)
  110.     s = re.ReplaceAllString(s, " ")
  111.     return s
  112. }
  113.  
  114. func DownloadFile(filepath, url string) error {
  115.     // Create the file
  116.     out, err := os.Create(filepath)
  117.     if err != nil {
  118.         return err
  119.     }
  120.     defer out.Close()
  121.  
  122.     // Get the data
  123.     resp, err := http.Get(url)
  124.     if err != nil {
  125.         return err
  126.     }
  127.     defer resp.Body.Close()
  128.  
  129.     // Write the body to file
  130.     _, err = io.Copy(out, resp.Body)
  131.     if err != nil {
  132.         return err
  133.     }
  134.  
  135.     return nil
  136. }

參考

拆解 Youtube 影片下載位置
[爬蟲實戰] 如何使用Python 爬蟲 (Python Crawler) 下載Youtube 影片 - YouTube

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