WinSock Manual HTTP File Upload - c++

Question

I am playing around writing some HTTP communication in C++ using the Winsock APIs. I have no trouble performing GET requests and receiving the response, however I am having a problem when trying to perform a file upload via a POST request.
So first of all, I will share the code of my PHP file which receives the upload request (upload.php):
<?php
if(isset($_FILES['file'])){
$errors= array();
$file_name = $_FILES['file']['name'];
$file_size =$_FILES['file']['size'];
$file_tmp =$_FILES['file']['tmp_name'];
$file_type=$_FILES['file']['type'];
$file_ext=strtolower(end(explode('.',$_FILES['file']['name'])));
if(empty($errors)==true){
move_uploaded_file($file_tmp,"uploads/".$file_name);
echo "Success";
}
}
else{
echo "Was no file";
}
?>
<form action="" method="POST" enctype="multipart/form-data">
<input type="file" name="file"/>
<input type="submit"/>
</form>
Now I know that there is nothing wrong with this code, because I succeed to perform a file upload to it by using WinInet APIs (HttpSendRequest). My WinInet code which works on this PHP file is comprised of the following main steps:
HttpOpenRequest(..., "POST", "uploader/upload.php", "HTTP/1.0", NULL, NULL, NULL, NULL)
HttpSendRequest with headers I set to: "Content-Type: multipart/form-data; boundary=---------FILE_BOUNDARY----------". I printed out the request body that was built by my program as you can see here, sorry I didn't print it out in a way which I could copy and paste here: http://i.imgur.com/mMmo7Xd.png
This works beautifully, the file is uploaded properly. However my problem arises when I try to "port" this code to use winsock API's instead of wininet. With winsock, as you may know, I must completely manually construct the whole request (headers and body). I assume this must be where my problem is, because the main body of the request itself is the same as when I am using wininet APIs. Here is a printout of my winsock request that is being sent: http://i.imgur.com/TkLNGrq.png
PS I have no idea why MessageBox put the boundary part of the header on another line, the is no "\r\n" there in my code. Could this have something to do with my issue? Here is my code for building the entire request string. Please don't give me pointers on security and buffer overruns, this is not production code:
wsprintfA(FullReqStr,
// Headers
"POST %s HTTP/1.0\r\n"
"Host: %s\r\n"
"Content-Type: multipart/form-data; boundary=---------FILE_BOUNDARY----------\r\n\r\n"
// Body
"-----------FILE_BOUNDARY----------\r\n"
"Content-Disposition: form-data; name=\"file\"; filename=\"file.log\"\r\nContent-Type: application/octet-stream\r\n\r\n"
"%s\r\n"
"-----------FILE_BOUNDARY----------\r\n"
"Content-Disposition: form-data; name=\"submit\"\r\n\r\n"
"Submit\r\n"
"-----------FILE_BOUNDARY------------\r\n",
GatePath, Server, FileBody
);
And yes the file bytes in the winsock request are different, I used different file bytes for testing. That is besides the point. Basically, when I send that request and receive the response, it hits the "Was no file" else in the PHP file. I feel like I must be missing some required field in the headers of my winsock request, one that is otherwise automatically added when using WinInet APIs. I cannot think of anything else, however I'm not sure what I'm missing.
Could anybody point me to what is wrong in my Winsock code? I would greatly appreciate it. Thank you. By the way please not I am not looking for any security or anything in my upload script, obviously. I'm just playing around trying to get this to work. It is not being applied to any system that needs to be secure or anything.
Thanks.

Answer 1

Looks like I didn't read the RFC closely enough. http://www.ietf.org/rfc/rfc1867.txt
I needed to add the "Content-Length" field to my HTTP header. Now I construct the body of the request first so I can take the length, and then construct the entire request using that. Working fine.