0

我有一个 Jpegs 图像流，我正在尝试使用 HTTP 将它们流式传输到 VLC

如果代码如下：

 public HttpListenerResponse StartListening(String where)
    {
        listener = new HttpListener();
        listener.Start();
        Console.WriteLine("listening on " + where);
        listener.Prefixes.Add(where);
        HttpListenerContext context = listener.GetContext();
        HttpListenerRequest request = context.Request;
        // Obtain a response object.
        HttpListenerResponse response = context.Response;
        return response;
    }
public void StartStream()
    {
        HttpListenerResponse response = StartListening("http://localhost:8080/");
        MemoryStream mem = null;

        for (;;)
        {
            Bitmap b = generateBitmap();
            //pictureBox1.Image = frm.GetFormImage();
            byte[] ar = BitmapToArray(b);


            // Construct a response.
            byte[] buffer = ar;
            response.ContentType = "multipart/x-mixed-replace; boundary=--testboundary";
            ASCIIEncoding ae = new ASCIIEncoding();
            byte[] boundary = ae.GetBytes("\r\n--testboundary\r\nContent-Type: image/jpeg\r\nContent-Length:" + buffer.Length + "\r\n\r\n");
            mem = new MemoryStream(boundary);
            mem.WriteTo(response.OutputStream);
            mem = new MemoryStream(buffer);
            mem.WriteTo(response.OutputStream);
        }   
        mem.Close();
        listener.Stop();    

    }

出于某种原因，如果我尝试在 Firefox 中打开流，它会返回全黑，如果我尝试使用 VLC 打开它，我会得到“无法打开流”

如果我只流式传输 1 个图像，Firefox 处理它没有问题。

提前谢谢，何塞

4

2 回答 2

3

您可以尝试一个多部分范围请求。VLC 可能正在请求“块”中的数据，但您的 HTTPHandler 没有提供该功能。下面是一些（冗长的）示例代码。尝试将音乐流式传输到我的 iPod Touch 时，我遇到了类似的问题。像浏览器中的魅力一样工作，但不适用于 Touch。事实证明，iPod 通过多个请求向我的处理程序请求 byte[] 块，但处理程序没有实现它需要的功能。

我在这里混合了一些我自己的库类，但你会很好地理解图片。

public abstract class MultipartRangeHandler : IHttpHandler
{
    protected const String HEADER_RANGE = "range";
    protected const String HEADER_CONTENT_TYPE = "Content-Type";
    protected const String HEADER_CONTENT_LENGTH = "Content-Length: ";
    protected const String HEADER_CONTENT_DISPOSITION = "Content-Disposition";
    protected const String HEADER_CONTENT_RANGE = "Content-Range";
    protected const String HEADER_BOUNDARY_DELIMETER = "--";
    protected const String HEADER_STATUS_PARTIAL_CONTENT = "Partial Content";

    private const char COMMA = ',';
    private const char EQUALS = '=';
    private const char NEW_LINE = '\n';

    protected const String QS_OBJECT_ID = "cid";

    public void ProcessRequest(HttpContext context)
    {
        if (StringUtils.isNullOrEmpty(context.Request.QueryString[QS_OBJECT_ID]))
        {
            sendResponse(400, "400 Bad Request", "No resource was specified in the query string to retrieve.", context);
        }
        else
        {
            ContentItem contentItem = getContentItem(context.Request.QueryString[QS_OBJECT_ID]);

            if (contentItem != null)
            {
                context.Response.Clear();
                context.Response.ClearHeaders();
                context.Response.ClearContent();

                if (context.Request.Headers[HEADER_RANGE] != null)
                {

                    string range = context.Request.Headers[HEADER_RANGE];
                    range = range.Substring(range.LastIndexOf(EQUALS) + 1);
                    bool isMultipartRange = range.Contains(COMMA.ToString());

                    if (!isMultipartRange)
                    {
                        addHeader(context.Response, HEADER_CONTENT_TYPE, contentItem.MimeType);
                        addHeader(context.Response, HEADER_CONTENT_DISPOSITION, "inline; filename=\"" + contentItem.Filename + "\"");

                        string[] startEnd = range.Split('-');

                        long startPos;

                        long.TryParse(startEnd[0], out startPos);

                        long endPos;
                        int fileSize = contentItem.FileBytes.Length;

                        if (startEnd.GetUpperBound(0) >= 1 && startEnd[1] != String.Empty)
                        {
                            long.TryParse(startEnd[1], out endPos);
                        }
                        else
                        {
                            endPos = fileSize - startPos;
                        }

                        if (endPos > fileSize)
                        {
                            endPos = fileSize - startPos;
                        }

                        context.Response.StatusCode = 206;
                        context.Response.StatusDescription = HEADER_STATUS_PARTIAL_CONTENT;
                        addHeader(context.Response, HEADER_CONTENT_RANGE, "bytes " + startPos + "-" + endPos + "/" + fileSize);

                        context.Response.BinaryWrite(ByteUtils.subByte(contentItem.FileBytes, (int)startPos, (int)(endPos - startPos) + 1));
                    }
                    else
                    {

                        string boundary = "waynehartmanansmach";
                        addHeader(context.Response, HEADER_CONTENT_TYPE, "multipart/byteranges; boundary=" + boundary);

                        List<string[]> ranges = new List<string[]>();
                        string[] multiRange = range.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
                        foreach (string mr in multiRange)
                        {
                            ranges.Add(mr.Split(new string[] { "-" }, StringSplitOptions.RemoveEmptyEntries));
                        }

                        //  process the list of ranges
                        foreach (string[] rangeArray in ranges.ToArray())
                        {
                            context.Response.Write(HEADER_BOUNDARY_DELIMETER + boundary + NEW_LINE);
                            context.Response.Write(HEADER_CONTENT_TYPE + ": " + contentItem.MimeType + NEW_LINE);
                            context.Response.Write(HEADER_CONTENT_RANGE + ": bytes " + rangeArray[0] + "-" + rangeArray[1] + "/" + contentItem.FileBytes + NEW_LINE + NEW_LINE);
                            long startPos = long.Parse(rangeArray[0]);
                            long endPos = long.Parse(rangeArray[1]);

                            context.Response.BinaryWrite(ByteUtils.subByte(contentItem.FileBytes, (int)startPos, (int)(endPos - startPos) + 1));

                            context.Response.Write(NEW_LINE);
                            context.Response.Flush();
                        }

                        context.Response.Write(HEADER_BOUNDARY_DELIMETER + boundary + HEADER_BOUNDARY_DELIMETER + NEW_LINE + NEW_LINE);
                    }
                }
                else
                {
                    context.Response.ContentType = contentItem.MimeType;
                    addHeader(context.Response, HEADER_CONTENT_DISPOSITION, "attachment; filename=\"" + contentItem.Filename + "\"");
                    addHeader(context.Response, HEADER_CONTENT_LENGTH, contentItem.FileBytes.Length.ToString());

                    context.Response.OutputStream.Write(contentItem.FileBytes, 0, contentItem.FileBytes.Length);
                }
            }
            else
            {
                sendResponse(404, "404 Not Found", "The resource requested does not exist.", context);                    
            }
        }
    }

    private void sendResponse(int statusCode, String status, String statusMessage, HttpContext context)
    {
        System.Text.StringBuilder data = new System.Text.StringBuilder();

        data.AppendLine("<html><body>");
        data.AppendLine("<h1>"+status+"</h1>");
        data.AppendLine("<p>"+statusMessage+"</p>");
        data.AppendLine("</body></html>");

        byte[] headerData = System.Text.Encoding.ASCII.GetBytes(data.ToString());

        context.Response.ContentType = "text/html";
        context.Response.StatusCode = statusCode;
        context.Response.Status = status;

        addHeader(context.Response, HEADER_CONTENT_LENGTH, headerData.Length.ToString());

        //context.Response.AddHeader("Content-Length: ", headerData.Length.ToString());
        context.Response.OutputStream.Write(headerData, 0, headerData.Length);
        context.Response.End();
    }

    protected void addHeader(HttpResponse response, String key, String value)
    {
        response.AddHeader(key, value);
    }

    protected abstract com.waynehartman.util.web.handlers.multipartrange.ContentItem getContentItem(String objectID);

    public bool IsReusable
    {
        get { return true; }
    }
}
于 2009-05-13T03:29:06.367 回答
0

设置您的前缀，然后调用Start().

从我在代码和其他地方看到的情况来看，您无法使用 HttpListener 流式传输数据。您可能必须将请求转发到另一个写回数据的本地 TCP 套接字。

于 2009-04-24T17:56:15.077 回答