/*
 * httphead - show http header of a website
 */

/*
 * Copyright (c) 2006 Andreas Jaggi <andreas.jaggi@waterwave.ch>
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <unistd.h>
#include <stdlib.h>
#include <netdb.h>

#include <errno.h>
#include <string.h>

#include "httphead.h"

const char usagemsg[] =
	"usage: httphead [-r] [-q] [-p port] [-s host-] [-d path] [-s host] URL\n"
	"\n"
	"options:\n"
	"    -p port    use this port instead of 80\n"
	"    -s host    use this host instead of the one specified in the URL\n"
	"    -d path    use this path instead of the one specified in the URL\n"
	"    -r         show sent request\n"
	"    -q         show only the recieved status code\n"
	" also: -v    show version\n"
	"       -h    display this help\n"
	"       -l    display (BSD) license\n"
	;

void usage ( );

void crlf ( int s );

char* gethost ( char* url );
char* getpath ( char* url );
char* getstatuscode ( char* response );

int main ( int argc, char* argv[] ) {

	int tmp;
	char* hend = NULL;
	char buff[HH_BUFFSIZE+1];

	char* url = NULL;

	char* host = NULL;
	char* path = NULL;
	int port = 80;

	int showrequest = 0;
	int statuscodeonly = 0;
	char* statuscode = NULL;

	struct hostent *remote_hostent = NULL;
	struct sockaddr_in *remote_host_addr = NULL;

	int sock;

	while ( (tmp = getopt(argc, argv, "qrd:s:p:hlv")) != -1 ) {
		switch ( tmp ) {
			case 'h':
				usage();
				exit(0);
			case 'l':
				license();
				exit(0);
			case 'v':
				version();
				exit(0);
			case 'p':
				port = atoi(optarg);
				break;
			case 's':
				host = optarg;
				break;
			case 'd':
				path = optarg;
				break;
			case 'q':
				statuscodeonly = 1;
				break;
			case 'r':
				showrequest = 1;
				break;
		}
	}

	if ( optind >= argc ) {
		usage();
		exit(0);
	}

	url = argv[optind];

	if ( path == NULL ) {
		path = getpath(url);
	}

	if ( host == NULL ) {
		host = gethost(url);
	}

	remote_hostent = gethostbyname(host);

	if ( remote_hostent == NULL ) {
		herror(NULL);
		exit(-1);
	}

	remote_host_addr = alloca(sizeof(struct sockaddr_in));
	remote_host_addr->sin_family = AF_INET;
	remote_host_addr->sin_addr = *((struct in_addr*) remote_hostent->h_addr);
	remote_host_addr->sin_port = port;

	if ( (sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1 ) {
		showerror("socket");
		exit(-1);
	}

	if ( connect(sock, (struct sockaddr*)remote_host_addr, sizeof(struct sockaddr_in)) == -1 ) {
		showerror("connect");
		exit(-1);
	}


	/* main */

	if ( showrequest ) {
		write(1, "GET ", 4);
		write(1, path, strlen(path));
		write(1, " HTTP/1.0", 9);
		crlf(1);
		write(1, "Host: ", 6);
		write(1, host, strlen(host));

		crlf(1);
		crlf(1);

		write(1, "Response:\n\n", 12);
	} 

	write(sock, "GET ", 4);
	write(sock, path, strlen(path));
	write(sock, " HTTP/1.0", 9);
	crlf(sock);
	write(sock, "Host: ", 6);
	write(sock, host, strlen(host));

	crlf(sock);
	crlf(sock);

	while ( (tmp = recv(sock, buff, HH_BUFFSIZE, 0)) > 0 ) {
		buff[tmp] = '\0';

		if ( (hend = strstr(buff, "\x0D\x0A\x0D\x0A")) != NULL) {
			tmp = hend-buff;
			*hend = '\n';
			*(hend+1) = '\0';
		}

		if ( statuscodeonly ) {
			if ( (statuscode = getstatuscode(buff)) != NULL ) {
				write(1, statuscode, 3);
				write(1, "\n", 1);
				break;
			}
		} else {
			write(1, buff, tmp);
		}

		if ( hend != NULL ) {
			break;
		}
	}

	if ( shutdown(sock, 2) == -1 ) {
		showerror("shutdown");
		exit(-1);
	}

	if ( close(sock) == -1 ) {
		showerror("close");
		exit(-1);
	}

	exit(0);
}

char* _gethoststart ( char* url ) {
	char* s = NULL;

	s = strstr(url, "http://");
	if ( s == NULL ) {
		s = strstr(url, "https://");
		if ( s == NULL ) {
			s = url; // assume that there is no http[s]:// prefix
		} else {
			s += 8;
		}
	} else {
		s += 7;
	}

	if ( s >= url + strlen(url) ) {
		return url;
	}

	return s;
}

int _gethostlen ( char* s ) {
	int e = 0;

	while ( *(s+e) != '/' && *(s+e) != '?' && *(s+e) != '\0' ) {
		e++;
	}

	return e;
}

char* getstatuscode ( char* s ) {
	char* htp = NULL;

	if ( (htp = strstr(s, "HTTP/")) != NULL ) {
		while ( *htp != '\0' && *htp != ' ' ) {
			htp++;
		}

		while ( *htp == ' ' ) {
			htp++;
		}

		if ( *htp == '\0' ) {
			htp = NULL;
		}
	}

	return htp;
}

char* getpath ( char* url ) {
	char* s = NULL;
	int e;

	s = _gethoststart(url);

	e = _gethostlen(s);

	s += e;

	if ( s >= url+strlen(url) ) {
		s = (char*)malloc(2*sizeof(char));
		*s = '/';
		*(s+1) = '\0';
	}

	return s;
}

char* gethost ( char* url ) {
	char* s = NULL;
	char* r = NULL;
	int e = 0;

	s = _gethoststart(url);

	e = _gethostlen(s);

	if ( e == 0 ) {
		return NULL;
	}

	r = (char*)malloc(sizeof(char)*(e+1));

	memcpy(r, s, e);

	r[e+1] = '\0';

	return r;
}

void crlf ( int s ) {
	write(s, "\x0D\x0A", 2);
}

void usage ( ) {
	write(1, usagemsg, strlen(usagemsg));
}