[SOLVED] Handle query strings using socket programming

[c00get]

Hi, I need to make a daemon which listens to port 81 for messages like localhost/message?command=move&dir=left
So far I made a daemon which serves as a simple stream server: I set up a socket to listen to a non-reserved port (like 9999), but I don't know how to read the query strings.

Linux distro: Kubuntu 9.04
Language: C

[gerard4143]

man recv

File: *manpages*, Node: recv, Up: (dir)

RECV(2) Linux Programmer's Manual RECV(2)



NAME
recv, recvfrom, recvmsg - receive a message from a socket

SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>

ssize_t recv(int sockfd, void *buf, size_t len, int flags);

ssize_t recvfrom(int sockfd, void *buf, size_t len, int flags,
struct sockaddr *src_addr, socklen_t *addrlen);

ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags);

for complete details open a terminal and type info revc or man recv

[jrop]

Are you having trouble with knowing where the query strings get passed to you or how to read data from the socket?

[c00get]

Are you having trouble with knowing where the query strings get passed to you or how to read data from the socket?

First of all, thanks for the replies.

I don't know where the query strings get passed. I tried with recv, but didn't manage to get something from it.

[jrop]

They get passed by the browser in the Http Request:

This is sort of a minimal HTTP Request:
<start HTTP Request>
GET [pathToPage]?[queryString] HTTP/1.1
Host: [yourhost]
[other headers here...]

<end HTTP Request>

Notice that the header region ends with two newlines.

Hope that helps.

[jrop]

Also, you might try getting a packet sniffer just to be able to see what "real" requests and responses look like. (Wireshark seems to be a good one)

[c00get]

I finally managed to get the query string. It worked with recv. I wasn't reading the buffer correctly because I didn't know the format. Thank you for your help.