How do I determine when there is no more data to read in a NetworkStream?

Question

I have a web app which connects to a server using a TCP connection and reads a binary document which it then writes to its response object. In other words it's transferring a file from a backend server using a custom protocol and returning that file to its client through HTTP.

The server sends a status code and a mime type, which I read successfully and then writes the contents of the file and closes the socket. This seems to work fine.

The client (a C# web app), reads the data:

     private NetworkStream stream_;

     public void WriteDocument(HttpResponse response)
     {
        while (stream_.DataAvailable)
        {
           const int bufsize = 4 * 1024;
           byte[] buffer = new byte[bufsize];
           int nbytes = stream_.Read(buffer, 0, bufsize);
           if (nbytes > 0)
           {
              if (nbytes < bufsize)
                 Array.Resize<byte>(ref buffer, nbytes);
              response.BinaryWrite(buffer);
           }
        }
        response.End();
     }

This seems to always exit the read loop before all the data has arrived. What am I doing wrong?

Answer 1

I would use the OutputStream directly with a general-purpose function. With the Stream, you can control Flush.

    public void WriteDocument(HttpResponse response) {
        StreamCopy(response.OutputStream, stream_);
        response.End();
    }

    public static void StreamCopy(Stream dest, Stream src) {
        byte[] buffer = new byte[4 * 1024];
        int n = 1;
        while (n > 0) {
            n = src.Read(buffer, 0, buffer.Length);
            dest.Write(buffer, 0, n);
        }
        dest.Flush();
    }