C Web Server - How to get URI? - c

Question

A Simple C Web Server: How to get the URI ?
Also:
Perhaps there is a way to simply see all of the incoming raw data ?
such as the whole GET request.. along with the URL .. etc.. ?
I searched the web but could not find any info.
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <err.h>
char response[] = "HTTP/1.1 200 OK\r\n"
"Content-Type: text/html; charset=UTF-8\r\n\r\n"
"test\r\n";
int main()
{
int one = 1, client_fd;
struct sockaddr_in svr_addr, cli_addr;
socklen_t sin_len = sizeof(cli_addr);
int sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock < 0)
err(1, "can't open socket");
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(int));
int port = 82;
svr_addr.sin_family = AF_INET;
svr_addr.sin_addr.s_addr = INADDR_ANY;
svr_addr.sin_port = htons(port);
if (bind(sock, (struct sockaddr *) &svr_addr, sizeof(svr_addr)) == -1) {
close(sock);
err(1, "Can't bind");
}
listen(sock, 5);
while (1) {
client_fd = accept(sock, (struct sockaddr *) &cli_addr, &sin_len);
printf("got connection\n");
if (client_fd == -1) {
perror("Can't accept");
continue;
}
write(client_fd, response, sizeof(response) - 1); /*-1:'\0'*/
close(client_fd);
}
}

Answer 1

Well, according to RFC 7230, the GET query should looks like:
GET /index.html HTTP/1.1
Host: www.example.org
So, when client connects, you must read query from client, and parse it:
/* data to store client query, warning, should not be big enough to handle all cases */
char query[1024] = "";
char page[128] = "";
char host[128] = "";
/* read query */
if (read(client_fd, query, sizeof query-1) > 0)
{
char *tok;
char sep[] * "\r\n";
char tmp[128];
/* cut query in lines */
tok = strtok(query, sep);
/* process each line */
while (tok)
{
/* See if line contains 'GET' */
if (1 == sscanf(tok, "GET %s HTTP/1.1", tmp))
{
strcpy(page, tmp);
}
/* See if line contains 'Host:' */
else if (1 == sscanf(tok, "Host: %s", tmp))
{
strcpy(host, tmp);
}
/* get next line */
tok = strtok(query, sep);
}
/* print got data */
printf("wanted page is: %s%s\n", host, page);
}
else
{
/* handle the error (-1) or no data to read (0) */
}