Error trying to send multipart form

Question

Hi, I'm trying to send a multipart/form-data with the following code:

HttpWebRequest^ request = dynamic_cast<HttpWebRequest^>(WebRequest::Create("http://the-server.com");
request->Method = "POST";
request->Host = "the-server";
request->ContentType = "multipart/form-data; boundary=AaB03x";

StreamWriter^ writer = gcnew StreamWriter(request->GetRequestStream());

writer->WriteLine("--AaB03x");
writer->WriteLine("Content-Disposition: form-data; name=\"first_field\"");
writer->WriteLine();
writer->WriteLine("the value");

writer->WriteLine("--AaB03x");
writer->WriteLine("Content-Disposition: form-data; name=\"second_field\"");
writer->WriteLine();
writer->WriteLine("the value");

.
.
.

writer->WriteLine("--AaB03x");
writer->WriteLine("--");

HttpWebResponse^ response = dynamic_cast<HttpWebResponse^>(request->GetResponse());

But then the server returns an error; it says that the stream ended unexpectedly. I used Wireshark to look at the data sent and really not all the fields were sent. The transmission ended abruptly in the midway. I noticed ContentLength was set to some value, I don't know if it was correct.

Do you have any idea what's happening? Do I have to set ContentLength manually?

Answer 1

Solved! There was an error here:

writer->WriteLine("--AaB03x");
writer->WriteLine("--");

Must be:

writer->WriteLine("--AaB03x--");

But anyway, that's not what I did. For some unknown reason, ContentLength was not being set properly, so that part of the data still wasn't getting sent. Since .Net is so quirky about this, I forgot this approach entirely and implemented my code using Sockets. Ugly but effective.

.Net needs some improvement on HttpWebRequest/HttpWebResponse