HTML5视频 - ashx处理程序 - 寻求

Question

我正在尝试将ashx处理程序用作HTML5视频源。我可以实现这一点，但我无法在已经缓冲的视频上进一步移动。

我可以看到使用标准MP4源的网络选项卡上，向前搜索会创建另一个请求，但是使用处理程序则不会。

其中一些视频超过1 GB。

到目前为止，我需要以下内容来使视频正常工作：

public void ProcessRequest(HttpContext context)
{
    context.Response.Buffer = false;
    context.Response.ContentType = "video/mp4";
    FileInfo file = new FileInfo(path);
    int len = (int)file.Length, bytes;
    context.Response.AppendHeader("content-length", len.ToString());
    byte[] buffer = new byte[1024];
    Stream outStream = context.Response.OutputStream;
    using (Stream stream = File.OpenRead(path))
    {
        while (len > 0 && (bytes = stream.Read(buffer, 0, buffer.Length)) > 0)
        {
            outStream.Write(buffer, 0, bytes);
            len -= bytes;
        }
    }
}

以下内容摘自Marck Gravells的帖子Best way to stream files in ASP.NET：

<video id="video-player" class="video-js vjs-default-skin" controls
     preload="auto" poster="MY_VIDEO_POSTER.jpg"
     data-setup="{}">
     <source src="/Handlers/VideoHandler.ashx" type='video/mp4'>
     <p class="vjs-no-js">
        To view this video please enable JavaScript, and consider upgrading to a web browser that
        <a href="http://videojs.com/html5-video-support/" target="_blank">supports HTML5 video</a>
     </p>
    </video>

我正在使用video.js，但是如果在浏览器中直接调用处理程序，同样会发生这种情况。

我该如何解决这个问题？很可能我错过了一些简单的东西。

更新

进一步查看后，我现在知道我需要“Accept-Ranges”。

我现在已经得到了。

context.Response.ContentType = "video/mp4";

var request = HttpContext.Current.Request;
FileInfo file = new FileInfo(filePath);
var responseLength = (int)file.Length;
var buffer = new byte[1024];
var startIndex = 0;

if (request.Headers["Range"] != null)
{
    var match = Regex.Match(request.Headers["Range"], @"bytes=(\d*)-(\d*)");
    startIndex = Parse<int>(match.Groups[1].Value);
    responseLength = (Parse<int?>(match.Groups[2].Value) + 1 ?? responseLength) - startIndex;
    context.Response.StatusCode = (int)HttpStatusCode.PartialContent;
    context.Response.Headers["Content-Range"] = "bytes " + startIndex + "-" + (startIndex + responseLength - 1) + "/" + responseLength;
}

context.Response.Headers["Accept-Ranges"] = "bytes";
context.Response.Headers["Content-Length"] = responseLength.ToString();
context.Response.Cache.SetCacheability(HttpCacheability.Public);

context.Response.Buffer = false;

借助Supporting resumable HTTP-downloads through an ASHX handler?的帮助，但现在写作过程中遇到了错误：

HttpException was unhandled by user code The remote host closed the connection. The error code is 0x800704CD.

我已经尝试了以下方法：

using (Stream stream = File.OpenRead(filePath))
{

    stream.Seek(startIndex, SeekOrigin.Begin);
    while ((responseLength - startIndex) > 0 && (bytes = stream.Read(buffer, 0, buffer.Length)) > 0)
    {
        response.OutputStream.Write(buffer, 0, bytes);
        responseLength -= bytes;
    }
}

并且

using (Stream stream = File.OpenRead(filePath))
{
    stream.Seek(startIndex, SeekOrigin.Begin);
    int bufferLength = buffer.Length, bytesRead;
    while (responseLength > bufferLength && (bytesRead = stream.Read(buffer, 0, bufferLength)) > 0)
    {
        response.OutputStream.Write(buffer, 0, bytesRead);
        responseLength -= bytesRead;
    }
    while (responseLength > 0 && (bytesRead = stream.Read(buffer, 0, responseLength)) > 0)
    {
        response.OutputStream.Write(buffer, 0, bytesRead);
        responseLength -= bytesRead;
    }
}

我该如何解决这个问题？

- BenG

Answer 1

最后一个错误是由Chrome引起的。

在Firefox中，以下内容可以正常工作。

如果有人知道为什么Chrome会取消连接，请分享一下。

    public void ProcessRequest(HttpContext context)
    {
        context.Response.AddHeader("content-disposition", "filename=" + Path.GetFileName(filePath));
        context.Response.ContentType = "video/mp4";

        var request = HttpContext.Current.Request;
        FileInfo file = new FileInfo(filePath);
        var responseLength = (int)file.Length;
        var buffer = new byte[512];
        var startIndex = 0;

        if (request.Headers["Range"] != null )
        {
            var match = Regex.Match(request.Headers["Range"], @"bytes=(\d*)-(\d*)");
            startIndex = Parse<int>(match.Groups[1].Value);
            responseLength = (Parse<int?>(match.Groups[2].Value) + 1 ?? responseLength) - startIndex;
            context.Response.StatusCode = (int)HttpStatusCode.PartialContent;
            context.Response.Headers["Content-Range"] = "bytes " + startIndex + "-" + (startIndex + responseLength - 1) + "/" + responseLength;
        }

        context.Response.Headers["Accept-Ranges"] = "bytes";
        context.Response.Headers["Content-Length"] = responseLength.ToString();
        context.Response.Cache.SetCacheability(HttpCacheability.Public);

        context.Response.BufferOutput = false;
        FileStream fileStram = new FileStream(filePath, FileMode.Open, FileAccess.Read);
        using (fileStram)
        {
            fileStram.Seek(startIndex, SeekOrigin.Begin);
            int bytesRead = fileStram.Read(buffer, 0, buffer.Length);
            while (bytesRead > 0)
            {
                context.Response.OutputStream.Write(buffer, 0, bytesRead);
                bytesRead = fileStram.Read(buffer, 0, buffer.Length);
            }
        }
    }

    public static T Parse<T>(object value)
    {
        // Convert value to string to allow conversion from types like float to int
        // converter.IsValid only works since .NET4 but still returns invalid values for a few cases like NULL for Unit and not respecting locale for date validation
        try { return (T)System.ComponentModel.TypeDescriptor.GetConverter(typeof(T)).ConvertFrom(value.ToString()); }
        catch (Exception) { return default(T); }
    }

- BenG

---

不确定为什么，但似乎是禁用缓冲的结果。但是，如果您修复Content-Range标头中的错误，其中应使用"/" + file.Length而不是"/" + responseLength，因为在下载过程中恢复下载时它们是不同的值，则即使在禁用缓冲并导致错误的情况下，它也将在Chrome中运行。如果要在IE中起作用，则需要添加ETAG。 - Michael

Answer 2

不需要打开和读取文件。我只需添加"Accept-Ranges"头并通过context.Response.TransmitFile翻译文件，就可以实现这个技巧。 现在视频在每个浏览器上都可以播放和寻找，如Chrome、Firefox。

 if (fi.Extension == ".mp4")
 {
    //Reset and set response headers. The Accept-Ranges Bytes header is important to allow resuming videos.
    context.Response.AddHeader("Accept-Ranges", "bytes");
 }
 docRepo.AddDocumentView(FileDetail.ID);
 context.Response.TransmitFile(HttpContext.Current.Server.MapPath(General.PathConstants.Documents + Id + fi.Extension));

- Sheeraz ALI