Thread: HTTP GET request

you might have to end it with \r\n\r\n that is how the server knows the request is done. If I remember correctly the request should look something like this in c...

Code:

     char request[] = "GET /index.html HTTP/1.1\r\n",
                                "host: somewebsite.com\r\n",
                                "\r\n";

Code:

request = malloc( ((tok - &(*argv[1])) - sizeof(argv[1])) + sizeof(char) * 17 + 1 + 4 );

what length are you trying to allocate here?

Code:

	sprintf(request, "%s %s %s", "GET", &(*argv[1]) + (tok - &(*argv[1])), "HTTP/1.0");

why not

Code:

	sprintf(request, "GET %s HTTP/1.0", tok);

Code:

	if (send(serverSocket, &request, sizeof(request), 0) < 0)
		error("send()");

sizeof (request) is 4 bytes
so you just sent the pointer to request - instead of the request itself...

use Wireshark to check what is being sent to network

MrAmazing and Vart - Thanks for the responses.

I caught the sprintf while debugging:

Code:

sprintf(request, "GET %s HTTP/1.0\r\nHOST:%s \r\n", &(*argv[1]) + (tok - &(*argv[1])), host);

That terrible malloc is because I need the length of the requested file, minus the domain (example.com).

size problems fixed:

Code:

i = send(serverSocket, &request, strlen(request) * sizeof(char), 0);
if (strlen(request) != i)
{
	printf("%d , %d\nMismatch!\n", i, strlen(request));
}
printf("request sent!\n%d\n", i);
printf("waiting for response...\n");
printf("%d", recv(serverSocket, &buffer, sizeof(buffer), 0));

now I'm hanging on the receive (why it's in the printf).

I can see a packet going out with a payload of 44bytes (in the case of the data I was using my request was 44 bytes). The rest are just SYN ACK (no response from server). the payload the of packet is:

Code:

00000   00 40 10 20 00 01 00 25  56 11 bf 49 08 00 45 00    .@. ...%V..I..E.
00010   00 60 b1 9f 40 00 40 06  70 dd c0 a8 01 02 4a 36    .`..@[email protected]
00020   0c 3b d6 cd 00 50 15 a0  25 7f d4 28 0b ce 80 18    .;...P..%..(....
00030   ff ff 0b fb 00 00 01 01  08 0a 29 f0 3c 27 94 35    ..........).<'.5
00040   d7 79 47 45 54 20 2f 69  6e 64 65 78 2e 70 68 70    .yGET /index.php
00050   20 48 54 54 50 2f 31 2e  30 0d 0a 48 4f 53 54 3a     HTTP/1.0..HOST:
00060   61 63 65 6e 73 75 6d 2e  63 6f 6d 20 0d 0a          acensum.com ..

compete (albeit rather messy right now) code:

Code:

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdbool.h>
#include <unistd.h>

#define BUFFSIZE 512

void error(char *msg);

int serverSocket;
int i = 0;
size_t bWritten, bTotal;
struct sockaddr_in serverAddr;
struct hostent *hostptr;
char *ip = "74.54.12.59";
char *tok, *host, *request, *buffer[BUFFSIZE];


int main (int argc, const char * argv[]) {
	printf("%s rev.0\n", argv[0]);
	if (argc < 2)
	{
		printf("Usage: %s [address]\n", argv[0]);
		exit(-1);
	}
	memset(&serverAddr, 0, sizeof(serverAddr));
	serverAddr.sin_family = AF_INET;
	serverAddr.sin_port = htons(80);
	serverAddr.sin_addr.s_addr = inet_addr(ip);
	tok = strpbrk(argv[1], "/");
	host = malloc(sizeof(char) * (tok - &(*argv[1]) + 1));
	strncpy(host, argv[1], tok - &(*argv[1]) );
	//disabled because xcode has a problem with gethostbyname()
	//char *test = "acenusm.com";
	//hostptr = gethostbyname(test);
	//printf("Resolved: %s\n", host);
	//printf("%s \n", hostptr->h_addr_list[0]);
	//these are really nasty but they work.
	printf("Requesting: %s\n", argv[1] + (tok - argv[1]));
	request = malloc( (tok - argv[1]) - strlen(argv[1]) + sizeof(char) * 26 + strlen(host) + 1 );
	sprintf(request, "GET %s HTTP/1.0\r\nHOST:%s \r\n", argv[1] + (tok - argv[1]), host);
	//free and Null pointer
	if(host)
	{
		free(host);
		host = NULL;
	}
	serverSocket = socket(AF_INET, SOCK_STREAM, 0);
	if (serverSocket < 0)
		error("socket()");
	if (connect(serverSocket, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) < 0)
		error("connect()");
	for (bTotal = 0; bTotal < strlen(request); bTotal += bWritten)
	{
		bWritten = write(serverSocket, &request[bTotal], strlen(request) - bTotal);
		if (bWritten == 0)
			break;
	}
	//i = send(serverSocket, &request, (strlen(request) + 1), 0);
	//if (strlen(request) + 1 != i)
	//	error("send()");
	printf("waiting for response...\n");
	//assuming recv return 0 when socket is closed)
	FILE *fp;
	fp = fopen("default.txt", "a");
	for(int j; j < BUFFSIZE; j++)
	{
		i = recv(serverSocket, &buffer+j, 4, 0);
		printf("%s\n", buffer);
	}
	free(request);
	request = NULL;
	
}

void error(char *msg)
{
	printf("Error: %s\n", msg);
	perror("");
	exit(0);
}