Question

Can anybody help me resolve the problem for posting multipart/form-data using below code.

I have no idea about how to do it.

Please refer function PostTrivialData from post Question

Answer 1

Here is the Code for Posting multipart data to URI:

public string UploadChatFile(Stream fileStream, string uri, string postData, string fileName)
        {
            string boundary = "----------------------------" +
            DateTime.Now.Ticks.ToString("x");

            HttpWebRequest httpWebRequest2 = (HttpWebRequest)WebRequest.Create(uri);
            httpWebRequest2.ContentType = "multipart/form-data; boundary=" +
            boundary;
            httpWebRequest2.Method = "POST";
            httpWebRequest2.KeepAlive = true;


            Stream memStream = new System.IO.MemoryStream();
            byte[] boundarybytes = System.Text.Encoding.UTF8.GetBytes("\r\n--" + boundary + "\r\n");

            memStream.Write(boundarybytes, 0, boundarybytes.Length);

            string headerTemplate = string.Format("Content-Disposition: form-data; name=\"postdata\"\r\n{0}\r\n\r\n", postData);

            byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(headerTemplate);

            memStream.Write(headerbytes, 0, headerbytes.Length);

            memStream.Write(boundarybytes, 0, boundarybytes.Length);

            headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n Content-Type: application/octet-stream\r\n\r\n";

            //string header = string.Format(headerTemplate, "file" + i, files[i]);
            string header = string.Format(headerTemplate, "uplTheFile", fileName);

            headerbytes = System.Text.Encoding.UTF8.GetBytes(header);

            memStream.Write(headerbytes, 0, headerbytes.Length);


            //FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);
            byte[] buffer = new byte[1024];

            int bytesRead = 0;

            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
            {
                memStream.Write(buffer, 0, bytesRead);

            }
            memStream.Write(boundarybytes, 0, boundarybytes.Length);
            fileStream.Close();

            httpWebRequest2.ContentLength = memStream.Length;
            Stream requestStream = httpWebRequest2.GetRequestStream();
            memStream.Position = 0;
            byte[] tempBuffer = new byte[memStream.Length];
            memStream.Read(tempBuffer, 0, tempBuffer.Length);
            memStream.Close();
            requestStream.Write(tempBuffer, 0, tempBuffer.Length);
            requestStream.Close();

            WebResponse webResponse2 = httpWebRequest2.GetResponse();

            Stream stream2 = webResponse2.GetResponseStream();
            StreamReader reader2 = new StreamReader(stream2);

            string responseString = reader2.ReadToEnd();


            return responseString;
        }

This will post image and also you can include your data to postData parameter. You need to handle this PostData server carefully as it’s combined with multipart content data.