Question

I Need to send files using HTTP protocols, but the question is should I use sockets because I have big files ? or I can use WinHttpApi such as :

BOOL HttpSendRequest(
  __in  HINTERNET hRequest,
  __in  LPCTSTR lpszHeaders,
  __in  DWORD dwHeadersLength,
  __in  LPVOID lpOptional,
  __in  DWORD dwOptionalLength
);

and use the lpOptional for the file I want ? and should I devide the file or this API handles big files?

Is there any limitation in files size if I used the HTTP apis and should I devide data?

Answer 1

HTTP uses TCP sockets for its connection:

HTTP communication usually takes place over TCP/IP connections. The
default port is TCP 80 [19], but other ports can be used. This does
not preclude HTTP from being implemented on top of any other protocol
on the Internet, or on other networks. […]

(It could in principle use something else, but that would be quite unusual.)

The advantage of using an HTTP over designing your own protocol over a socket is that there are plenty of existing HTTP libraries (amongst other arguments). You would have to define your own little protocol anyway, if only to tell the remote party when the file starts and stops.

A few points that HTTP helps with:

• It can tell you when you’ve finished reading a file, using the Content-Length header or chunked transfer encoding. This is necessary because you can’t generally distinguish clean and abrupt connection closures in TCP (API with a function like isConnected aren’t enough).
• Should the connection fail abruptly on a large file, you could make use of the Range header to specify which portion of the file to get. (You could do parallel streaming with it.)

If you do choose to use HTTP, try to read a bit more about it though. You may actually find that web servers and web clients already implement what you need. I’m not sure what lpOptional is about, but you should specify the file you want to get in the URL you construct. (Build your own URL space on your server.)