Question

I’m trying to write a TCP client that does the following things:

1. Establish TCP connection to webserver
2. Accept GET request command from user's console
3. Client should get a reply back from webserver after each GET request.

I’m having a difficult time for the 3rd condition. I did not receive any response back from the webserver.

Here is my code:

    s = connectTCP(host, service);
 while (fgets(buf, sizeof(buf), stdin)) {
   buf[LINELEN-2]='\r';    /* ensure catridge return   */
   buf[LINELEN-1]='\n'; /* ensure line feed return  */
   buf[LINELEN] = '\0'; /* ensure line null-terminated */
   outchars = strlen(buf);
   (void) write(s, buf, outchars);
   printf("Start reading from socket...\n");
   fflush(stdout);
   while( (n = read(s, buf, LINELEN)) > 0) {
    buf[n] = '\0';  /* ensure null-terminated */
    (void) fputs( buf, stdout );
    fflush(stdout);
   }
 }

Answer 1

An HTTP request is terminated with two carriage-return–linefeed (“\r\n\r\n”) sequences. The way you’re constructing your request won’t even ensure it has one. Maybe instead something like:

while (fgets(buf, sizeof(buf) - 3, stdin)) {
    size_t outsz = strlen(buf);
    if (outsz > 0 && buf[outsz - 1] == '\n')
        outsz--;
    strcpy(buf + outsz, "\r\n\r\n");
    write(s, buf, outsz + 4);