301/302 error in http c client sockets - c

Question

I am making a http c client socket. So far i have made a custom url parser and now the problem is connecting to absolute urls. The program works fine with relative urls but not absolute ones.
Here is a sample output for the results of both absolute and relative urls:
absolute url: http://www.google.com
relative url : http://techpatterns.com/downloads/firefox/useragentswitcher.xml
In an absolute url it gives a 301/302 status code while in a relative url the status is 200 OK
Here is a sample code of the key areas
char ip[100],*path, *domain, *abs_domain, *proto3;
char *user_agent = "Mozilla/5.0 (Windows NT 6.2; WOW64; rv:31.0) Gecko/20100101 Firefox/31.0";
char *accept_type = "Accept: text/html, application/xhtml+xml, */*\r\nAccept-Language: en-US\r\n";
char *encoding = "Accept-Encoding: gzip, deflate\r\n";
char *proxy_conn = "Proxy-Connection: Keep-Alive\r\n";
char hostname[1000];
url:
fgets(hostname,sizeof(hostname), stdin);
for(i=0; i<strlen(hostname);i++){//remove new line
if(hostname[i]=='\n'){
hostname[i]='\0';
}
}
proto3 = get_protocol(hostname); //get protocol i.e. http, ftp, etc
//get domain ie http://mail.google.com/index -> mail.google.com
//http://www.google/com/ssl_he -> www.google.com
domain = get_domain(hostname);
if(strlen(domain)==0){
printf("invalid url\n\n");
goto url;
}
abs_domain = get_abs_domain(hostname);//gets abs domain google.com, facebook.com etc
path = get_path(hostname);
//getting the ip address from the hostname
if ( (he = gethostbyname( abs_domain ) ) == NULL)
{
printf("gethostbyname failed : %d" , WSAGetLastError());
goto url;
}
//Cast the h_addr_list to in_addr , since h_addr_list also has the ip address in long format only
addr_list = (struct in_addr **) he->h_addr_list;
for(i = 0; addr_list[i] != NULL; i++)
{
//Return the first one;
strcpy(ip , inet_ntoa(*addr_list[i]) );
}
clientService.sin_addr.s_addr = inet_addr(ip);
clientService.sin_family = AF_INET;
clientService.sin_port = htons(80);
sprintf(sendbuf, "GET /%s HTTP/1.1\r\n%sUser-Agent: %s\r\nHost: %s\r\n\r\n", path,accept_type,user_agent, abs_domain);
Brief exlanation of the code:
i.e. if the url entered by the user is http://mail.deenze.com/control_panel/index.php
the protocol will be -> http
the domain will be -> mail.deenze.com
the abs_domain will be -> deenze.com
the path will be control_panel/index.php
Finally this values in conjunction with the user agent will be used to send the data.

Answer 1

301 and 302 status codes are redirects, not errors. They indicate that you should try the request at a different URL instead.
In this case, it looks like despite the fact that you entered the URL http://www.google.com/, the Host header you are sending only includes google.com. Google is sending you back a redirect telling you to use www.google.com instead.
I notice that you seem to have a get_abs_domain function that is stripping the www off; there is no reason you should do this. www.google.com and google.com are different hostnames, and may give you entirely different contents. In practice, most sites will give you the same result for them, but you can't depend on that; some will redirect from one to the other, some will simply serve up the same content, and some may only work at one or the other.
Instead of trying to rewrite one to the other, you should just follow whatever redirect you are returned.
I would recommend using an existing HTTP client library rather than trying to write your own (unless this is just an exercise for your own edification). For example, there's cURL if you want to be portable or HttpClient if you only need to work on Windows (based on your screenshots, I'm assuming that's the platform you're using). There is a lot of complexity in writing an HTTP client that can actually handle most of the web; SSL, compression, redirects, chunked transfer encoding, etc.

Answer 2

#Brian Campbell, i think the problem was the www, because if i use www.google.com it gives me a redirect url: https://www.google.com/?gws_rd=ssl same as my browser, but because it is a https i think i will have to use ssl, thank for your answer
I cant copy paste the text in my terminal but i have increase the fonts for visibility purposes