invoking web service using httprequest - asp.net

Question

i have a web service which contains a method like the following
[WebMethod]
public string UploadFile(byte[] bytes, string file_name)
{
}
i want to invoke this web service method using HttpWebRequest so that i can stream the file without buffering in memory. How can do it... i tried to invoke it as follows
HttpWebRequest hw = HttpWebRequest.Create("http://localhost/xxx/xxx.asmx/Upload") as HttpWebRequest;
hw.ContentType = "application/x-www-form-urlencoded";
hw.AllowWriteStreamBuffering = false;
hw.Method = "POST";
hw.UnsafeAuthenticatedConnectionSharing = true;
hw.UserAgent = "test type";
hw.Credentials = CredentialCache.DefaultCredentials;
FileInfo fi = new FileInfo("C:/Documents and Settings/Administrator/Desktop/a.txt");
string bytes = "bytes=";
byte[] by = UTF8Encoding.UTF8.GetBytes(bytes);
byte[] fn = UTF8Encoding.UTF8.GetBytes("&file_name=a.txt");
hw.ContentLength = by.Length+fi.Length+fn.Length;
using (Stream postStream = hw.GetRequestStream())
{
FileStream br = new FileStream("C:/Documents and Settings/Administrator/Desktop/a.txt", FileMode.Open, FileAccess.Read);
postStream.Write(by, 0, by.Length);
byte[] buffer = new byte[1024];
int bytesRead = 0;
while (true)
{
bytesRead = br.Read(buffer, 0, buffer.Length);
if (bytesRead == 0)
break;
postStream.Write(buffer, 0, bytesRead);
}
br.Close();
postStream.Write(fn, 0, fn.Length);
postStream.Write(ct, 0, ct.Length);
}
// HERE :
using (HttpWebResponse response = hw.GetResponse() as HttpWebResponse)
{
StreamReader reader = new StreamReader(response.GetResponseStream());
string sssdd = reader.ReadToEnd();
}
but it show a message "The remote server returned an error: (500) Internal Server Error." while executing **// HERE : ** marked line.
btw: i am using asp.net 2.0 and i am not allowed to use proxy class as my requirement is to stream the data for large file. Thanks in advance

Answer 1

Open up http://localhost/xxx/xxx.asmx/Upload in your browser and ASP.NET will give you an example POST requrest you'll need to send in order to invoke the method. Start from there on.

Answer 2

It's been a while since I messed with this stuff, but I think you can get at the underlying HttpRequest in the proxy class. Probably alot easier than ginning up your own SOAP to POST.

Answer 3

If it says that the remote server returned an error, then you should look on the remote server to see what the error was. Look in the Event Log on the server for events at around the time you received the error.

Answer 4

Remove these lines:
postStream.Write(by, 0, by.Length);
.
.
.
postStream.Write(fn, 0, fn.Length);
postStream.Write(ct, 0, ct.Length);