sending HTTP POST data with Socket

**Overtaker** · 09-06-2006

Hi Im trying to send a HTTP POST Request data content to a server using C socket
Everything seemed to work fine except this part

fprintf(http->file, "POST http://some url with POST form in php HTTP/1.1\r\n");
fprintf(http->file, "Host: hostname\r\n");
fprintf(http->file, "Content-Type: applicationx-www-form-urlencoded\r\n");
fprintf(http->file, "Content-Length: 10\r\n\r");
fprintf(http->file, "name=kkkkk\r\n");
fprintf(http->file, "\r\n");

http->file is file pointer to an open socket

the page on the server looks something like this

<html>
<head>
</head>
<body>

</Form>
<?php
$name = $_REQUEST[name];
if($name == NULL)
{
print('<Form action=info.php method=POST><input type="text" name="name"/><input type="submit"/></FORM>');
}
else
{
print($name);
}
?>
</body>
</html>

however when I tried to run the program
it gives me

<TITLE>400 Bad Request</TITLE>
</HEAD><BODY>
<H1>Bad Request</H1>
Your browser sent a request that this server could not understand.<P>
Request header field is missing colon separator.<P>
<PRE>
name%3Dkkkkk</PRE>
<P>
</BODY></HTML>

I only encountered the above problem if i included the POST data content in the request

fprintf(http->file, "Content-Length: 10\r\n\r");
fprintf(http->file, "name=kkkkk\r\n");

do you guys have any idea where did i go wrong ?
thanks

**Dave_Sinkula** · 09-06-2006

Originally Posted by Overtaker

I only encountered the above problem if i included the POST data content in the request

Code:

fprintf(http->file, "Content-Length: 10\r\n\r");
fprintf(http->file, "name=kkkkk\r\n");

do you guys have any idea where did i go wrong ?

Merely a guess -- is the extra \r supposed to be there?

**anonytmouse** · 09-07-2006

Originally Posted by Dave_Sinkula

Merely a guess -- is the extra \r supposed to be there?

Nearly, the request headers should be terminated by cr-lf-cr-lf, so the final '\n' is missing.

**Overtaker** · 09-07-2006

sorry I don't get it, what is cr-lf ?
is it supposed to be like this ?

Code:

fprintf(http->file, "Content-Length: 10\r\n");
fprintf(http->file, "name=kkkkk\r\n\n");

**itsme86** · 09-07-2006

No. The \r and \n should come in pairs (\r\n). As was previously noted, you ended up doing 2 \r in a row (you're missing a \n).

**Salem** · 09-07-2006

Of course knowing which machine you're running on would help.
As would whether said "file" is opened in binary or text mode.

Then perhaps we could figure out which set of end-of-line translations are being performed (or not).

@OP.
Get yourself a copy of www.ethereal.com and compare what a real web browser does with the request compared to what your code produces.
The answer is in the difference between the two.

**maxorator** · 09-07-2006

First you must connect to the correct server, then, send a request like this:

Code:

fprintf(http->file, "POST /index.php HTTP/1.1\r\n");
fprintf(http->file, "Host: www.yourhost.com\r\n");
fprintf(http->file, "Content-Type: applicationx-www-form-urlencoded\r\n");
fprintf(http->file, "Content-Length: 10\r\n\r\n");
fprintf(http->file, "name=kkkkk\r\n\r\n");

You must use relative path from the server root after post, not the host name of that site.

**Overtaker** · 09-07-2006

Hi
thanks for the replies

I tried

Code:

fprintf(http->file, "POST /index.php HTTP/1.1\r\n");
fprintf(http->file, "Host: www.yourhost.com\r\n");
fprintf(http->file, "Content-Type: applicationx-www-form-urlencoded\r\n");
fprintf(http->file, "Content-Length: 10\r\n\r\n");
fprintf(http->file, "name=kkkkk\r\n\r\n");

but I got this instead

Code:

HTTP/1.1 200 OK
Date: Thu, 07 Sep 2006 14:59:32 GMT
Server: Apache/1.3.34 (Unix) mod_perl/1.29
Transfer-Encoding: chunked
Content-Type: text/html

95
<html>
<head>
</head>
<body>

</Form>
<Form action=info.php method=POST><input type="text" name="name"/><input type="submit"/></FORM></body>
</html>

0

This is just my guess, if

Code:

fprintf(http->file, "POST /index.php HTTP/1.1\r\n");
fprintf(http->file, "Host: www.yourhost.com\r\n");
fprintf(http->file, "Content-Type: applicationx-www-form-urlencoded\r\n");
fprintf(http->file, "Content-Length: 10\r\n\r\n");

supposed to be the headers

then

Code:

fprintf(http->file, "name=kkkkk\r\n\r\n");

supposed to be the body, maybe I need to write it on difference phase instead all of them together ?

**maxorator** · 09-07-2006

No-no-no... It receives the whole thing and then sends the whole thing, you can't do it like that.
You just have to find a way to separate them from each other

**Overtaker** · 09-07-2006

well i still cant seem to get around it at all
the server im sending the POST request is Apache
I read somewhere that the Server will wait if I actually just send up to Content-Length: 10\r\n\r\n
but when i tried to send just up to that, the Server doesn't seem to wait cos' im getting the Response straight away

will pasting my entire code here help ?

**maxorator** · 09-07-2006

This is normal. All browsers separate headers and content and then read the headers and display the content. There is no way to get only the body because header is a critical part of a web page. Better start thinking how you are going to separate header and content.

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