[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

package gotube

import (
    "fmt"
    "io"
    "io/ioutil"
    "log"
    "net/http"
    "net/url"
    "os"
    "path/filepath"
    "regexp"
    "strings"
)

const userAgent = `Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0`

type Youtube struct {
    videoID  string
    VideoURL string
    VideoInfo
}

type VideoInfo struct {
    URL     string
    Quality string
    Ext     string
    Name    string
}

func (y *Youtube) api(method string) ([]byte, error) {
    urlIndex := "http://www.youtube.com/" + method
    req, err := http.NewRequest(http.MethodGet, urlIndex, nil)
    if err != nil {
        return nil, err
    }
    req.Header.Add("User-Agent", userAgent)

    q := req.URL.Query()
    q.Add("video_id", y.videoID)
    req.URL.RawQuery = q.Encode()
    log.Printf("Request api url=%s", req.URL)

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        return nil, err
    }
    defer resp.Body.Close()

    body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return nil, err
    }

    return body, nil
}

func (y *Youtube) getVideoInfo() error {
    body, err := y.api("get_video_info")

    m, err := url.ParseQuery(string(body))
    if err != nil {
        return err
    }

    y.VideoInfo.Name = m.Get("title")

    qs := m.Get("url_encoded_fmt_stream_map")
    qs = strings.Replace(qs, ",", "&", -1)
    values, err := url.ParseQuery(qs)
    if err != nil {
        return err
    }

    y.VideoInfo.Quality = values.Get("quality")
    y.VideoInfo.URL = values.Get("url")
    ext := strings.Split(values.Get("type"), ";")
    ext = strings.Split(ext[0], "/")
    y.VideoInfo.Ext = ext[1]

    log.Printf("Video: %+v\n", y.VideoInfo)
    return nil
}

func (y *Youtube) GetVideo() error {
    parse := strings.Split(y.VideoURL, "?")
    paras, err := url.ParseQuery(parse[1])
    if err != nil {
        return err
    }

    y.videoID = paras.Get("v")
    err = y.getVideoInfo()
    if err != nil {
        return err
    }

    fileName := fmt.Sprintf("%s.%s", FileNameCorrect(y.Name), y.Ext)
    path := filepath.Join(".", fileName)
    if err := DownloadFile(path, y.URL); err != nil {
        return err
    }

    return nil
}

func FileNameCorrect(s string) string {
    var re = regexp.MustCompile(`[\/:*?"<>|]`)
    s = re.ReplaceAllString(s, " ")
    return s
}

func DownloadFile(filepath, url string) error {
    // Create the file
    out, err := os.Create(filepath)
    if err != nil {
        return err
    }
    defer out.Close()

    // Get the data
    resp, err := http.Get(url)
    if err != nil {
        return err
    }
    defer resp.Body.Close()

    // Write the body to file
    _, err = io.Copy(out, resp.Body)
    if err != nil {
        return err
    }

    return nil
}

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