Question

我修改了用C＃编写的Youtube Downloader类，以便在Windows手机上使用它。我的结果如下。但是当我打电话给dw（）;我从e.Result.Read（buffer，0，buffer.Length）行的Web浏览器中获得了一个File-not-found-exception。我当然知道这意味着什么，但我不知道如何解决它。所以我有两个问题：为什么我的代码不起作用？或者是否有其他方法可以在WindowsPhone 7上下载Youtube视频？（就像图书馆或免费的代码片段一样......）谢谢。

class YoutubeDownload
{
    string youtubeurl;
    string fileext;

    private WebClient webClient = new WebClient();

    public void dw()
    {
        youtubeurl = "http://www.youtube.com/watch?v=locIxsfpgp4&feature=related";
        webClient.DownloadStringCompleted += new DownloadStringCompletedEventHandler(client_DownloadStringCompleted);
        webClient.DownloadStringAsync(new Uri(youtubeurl));
    }

    void client_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
    {
        string rawHtml = e.Result;
        string getUrl = "http://www.youtube.com/get_video.php?video_id={0}&amp;t={1}";
        Regex _titleRegex = new Regex("'VIDEO_TITLE': '(.+)',");
        Regex _qualiRegex = new Regex("\"fmt_map\": \"([0-9]{2})");
        Regex _idRegex = new Regex("\",\\s*\"t\":\\s*\"([^\"]+)");

        Match title = _titleRegex.Match(rawHtml);
        Match id = _idRegex.Match(rawHtml);
        Match quali = _qualiRegex.Match(rawHtml);

        string videotitle = title.Groups[1].Value;
        string videoid = youtubeurl.Substring(youtubeurl.IndexOf("?v=") + 3);
        string id2 = id.Groups[1].Value.Replace("%3D", "=");
        string dlurl = string.Format(getUrl, videoid, id2);

        fileext = "flv";
        if (rawHtml.Contains("'IS_HD_AVAILABLE': true")) // 1080p/720p
        {
          dlurl += "&fmt=" + quali.Groups[1].Value;
          fileext = "mp4";
        }
        else
        {
          dlurl += "&fmt=" + quali.Groups[1].Value;
          if (quali.Groups[1].Value == "18") // Medium
            fileext = "mp4";
          else if (quali.Groups[1].Value == "17") // Mobile
            fileext = "3gp";
        }
        webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted);
        webClient.OpenReadAsync(new Uri(dlurl));
    }

    void client_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
    {
        var file = IsolatedStorageFile.GetUserStoreForApplication();
        file.CreateDirectory("YoutubeDownloader");

        using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream("file." + fileext, System.IO.FileMode.Create, file))
        {
            byte[] buffer = new byte[1024];
            while (e.Result.Read(buffer, 0, buffer.Length) > 0)
            {
                stream.Write(buffer, 0, buffer.Length);
            }
        }
    }
}

Answer 1

当您将结果中的数据复制到隔离存储时，您总是在写入缓冲区的全部内容，无论您阅读的内容多少。你的循环应如下所示：

using (var stream = new IsolatedStorageFileStream("file." + fileext,
                                                  FileMode.Create, file))
{
    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = e.Result.Read(buffer, 0, buffer.Length)) > 0)
    {
        stream.Write(buffer, 0, bytesRead);
    }
}

（我还没有检查过那是不是错了，但听起来有点帮助......）

免责声明：我在Google工作，但我不知道您在YouTube许可方面所做的任何事情的合法性。请不要将此答案视为来自Google的任何意见。就我而言，这个答案纯粹是对一些常规流处理的修复。

Youtube Class无法正常工作

1 个答案: