Answer 1

Yeah,  if you need intermediate progress  indications, you should upload  the data asynchronously.

For that, get the stream as before..

Stream requestStream = request.GetRequestStream();

Byte [] photo = readPhotograph(..); // get the photo into a byte array. Or alternately, read from a stream.

int totalSize = photo.Length;

int offset = 0;
int totalWritten = 0;

void ReadCallback(IAsyncResult ar)
{
Stream stream = ar.AsyncState as Stream;
try
{
int written = stream.EndRead(ar);
offset += written;
totalWritten += written;
// here, update dialog box.
this.updateProgress(totalWritten, totalSize);

if (totalWritten < totalSize)
{
    int chunkSize = Math.Min(1024, (totalSize-totalWritten));
   // kick off another async write
   stream.BeginWrite(photo, offset, chunkSize, new AsyncCallback(ReadCallback), stream);
}
}
}

The code snippet needs some work to separate out state variables, but you get the idea...
int chunkSize = Math.Min(totalSize, 1024) // write in 1k chunks.
requestStream.BeginWrite(photo, 0, chunkSize, new AsyncCallback(WriteCallback), requestStream);

in your callback...

Answer 3

That is a good point, Dave. I had'nt thought about the fact that this would only track completions on the client, not the actual reception of data on the server.

Also, you made some good points about chunk sizes.

Answer 4

Thanks Feroze and Dave,

I will try HttpWebRequest.ContentLength or HttpWebRequest.SendChunked.


Veena

Answer 5

I am sorry to get back so late.
But I can not find a way to read a requestStream (no beginRead). I wrote a code like this


 StreamReader GetUrlStream(string url, HttpWebRequest webRequest, Dictionary<string, string> postKeys)
        {
            try
            {
                if (webRequest == null)
                {
                    webRequest = (HttpWebRequest)System.Net.WebRequest.Create(url);
                }

               
                webRequest.Credentials = new NetworkCredential("VersentiaUser", "password");          

                webRequest.Method = "POST";
                webRequest.ContentType = "application/x-www-form-urlencoded";
                webRequest.SendChunked = true;
              
                ms = AddPostKeys(postKeys);
                totalSize = (int)ms.Length;
                webRequest.ContentLength = totalSize;            

               
               
               Stream requestStream =  webRequest.GetRequestStream();
               
                chunkSize = Math.Min(2048 , totalSize);

                requestStream.BeginWrite(ms.ToArray(), 0, chunkSize, WriteCallback, requestStream);

              
                ms.Close();
                ms.Dispose();               
                startTime = DateTime.Now;             

              
                WebResponse response  = (HttpWebResponse)webRequest.GetResponse();
                endTime = DateTime.Now;

                Encoding enc = Encoding.GetEncoding(1252);

           
                var  strResponse = new StreamReader(response.GetResponseStream(), enc);

                return strResponse;
            }
            catch (WebException ex)
            {
               
                return null;
            }
           
        }


        private void WriteCallback(IAsyncResult asynchronousResult)
        {
            Stream requestStream = (Stream) asynchronousResult.AsyncState;
            requestStream.EndWrite(asynchronousResult);

            totalWritten += chunkSize;
            chunkSize = Math.Min(2048, (totalSize - totalWritten));

            if (totalWritten < totalSize)
            {
                requestStream.BeginWrite(ms.ToArray(), totalWritten, chunkSize, WriteCallback, requestStream);
               
            }
            requestStream.Close();
            requestStream.Dispose();
           
        }

But I got Exception that "Concurrent IO read write operation is not allowed".

Please help.

Veena

Answer 6

Sorry if I get you on another track without looking at your code first, but be sure to also check out the backgroundworker component: http://msdn.microsoft.com/en-us/library/8xs8549b.aspx

Answer 7

Thanks Naicul,

But I am looking for something which shows upload  file status  as file  is uploaded  to server. Actually HttpWebRequest and HttpWebresponse classes  has no arrangement to write requestStream or read  responseStream in steps, so The status comes to know when the file is uploaded completely. That's why uploadBar looks frozen  until I get the response  back.

I am uploading pictures, I want to give assurance of upload progress  to user  by showing  uploadRate and showing a continuous upload bar.

If you have any idea, please help.


Veena

Answer 9

Thanks Naicul,

But I am uploading a file  from my computer to web  server and I find no way to know how much data is uploaded  until complete  file is uploaded.

I was trying to read the requestStream in chunks , but no luck.

Veena

Answer 11

Sorry, Not yet.