How to send html files with http protocol over tcp in c language?

Question

I 'm writing a HTTP web server that can respond to PUT, GET , ... requests when GET request is sent from a browser , the browser should receives the related HTML file I have analyzed the GET request in the Wireshark it sends the whole HTML file of the website and then the browser requests the rest of the files that are used in the HTML file

My problem is that when I use the send() function and send and HTTP respond to the GET requests the body part of the HTTP message that contains the HTML file is not displayed correctly in the browser when it is read from a HTML file but when I type the HTML file into a string variable and give it to the send() function it works.

here is my code:

char send_buffer[1000];
FILE *sendFile = fopen("foo.txt", "r");
while( !feof(sendFile) )
{
int numread = fread(send_buffer, sizeof(unsigned char), 1000, sendFile);
if( numread < 1 ) break; // EOF or error

char *send_buffer_ptr = send_buffer;
do
{
    int numsent = send(connected, send_buffer_ptr, numread, 0);
    if( numsent < 1 ) // 0 if disconnected, otherwise error
    {
        if( numsent < 0 )
        {
            if( WSAGetLastError() == WSAEWOULDBLOCK )
            {
                fd_set wfd;
                FD_ZERO(&wfd);
                FD_SET(connected, &wfd);

                timeval tm;
                tm.tv_sec = 10;
                tm.tv_usec = 0;

                if( select(0, NULL, &wfd, NULL, &tm) > 0 )
                    continue;
            }
        }

        break; // timeout or error
    }

    send_buffer_ptr += numsent;
    numread -= numsent;
}
while( numread > 0 );
}

I have tested the code with the foo file containing the HTTP header and some HTML code as below:

HTTP/1.1 200 OK
Content-length: 60
Content-Type: text/html


<!DOCTYPE html>
<html>
<body>

<h1>My First Heading</h1>

<p>My first paragraph.</p>

</body>
</html>

I have also tries sending the header with a separate send function and the HTML file with another send function right after it.

user149341 · Accepted Answer · 2014-11-21 16:20:50Z

1

The Content-Length header in your response is incorrect. The body of your response is over 100 bytes long, not 60 bytes like the header says. (If your file uses CR+LF line endings, it's actually even longer.)

In general, the Content-Length header should be generated by the web server, as it must exactly match the size of the response body. Storing it in the response is far too prone to errors.

answered Nov 21, 2014 at 16:20

user149341

Sign up to request clarification or add additional context in comments.

3 Comments

Freelancer Over a year ago

I had no problem sending just part of the HTML code by decreasing the content length ,the main problem is that when reading the same HTML code from the file and sending it to the browser it is just displayed as the HTML code

Freelancer Over a year ago

After sending the file with the exact content-length it worked! Thanks a lot.

Remy Lebeau Over a year ago

Consider using Transfer-Encoding: chunked in the response, then you don't need a Content-Length header at all, you can send the file data as you are reading it from the file, and can signal the client with a 0-length chunk at the end when finished.

Collectives™ on Stack Overflow

How to send html files with http protocol over tcp in c language?

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related