Select Git revision
http-server.c 13.47 KiB
/*
** http-server.c
*/
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <strings.h>
#include <sys/select.h>
#include <sys/sendfile.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <time.h>
void reset_game();
void reset_user(int sockfd);
void set_user(int sockfd);
void user_ready(int sockfd);
// constants
static char const * const HTTP_200_FORMAT = "HTTP/1.1 200 OK\r\n\
Content-Type: text/html\r\n\
Set-Cookie: name=foo\r\n\
Content-Length: %ld\r\n\r\n";
static char const * const HTTP_400 = "HTTP/1.1 400 Bad Request\r\nContent-Length: 0\r\n\r\n";
static int const HTTP_400_LENGTH = 47;
static char const * const HTTP_404 = "HTTP/1.1 404 Not Found\r\nContent-Length: 0\r\n\r\n";
static int const HTTP_404_LENGTH = 45;
static int user1 = -1;
static int user1_start = 0;
char user1_guesses[100][100];
int user1_guess_number = 0;
static int user2 = -1;
static int user2_start = 0;
char user2_guesses[100][100];
int user2_guess_number = 0;
int gameover = 0;
static char *webpage;
// represents the types of method
typedef enum
{
GET,
POST,
UNKNOWN
} METHOD;
static bool handle_http_request(int sockfd)
{
// try to read the request
char buff[2049];
int n = read(sockfd, buff, 2049);
if (n <= 0) {
if (n < 0)
perror("read");
else
printf("socket %d close the connection\n", sockfd);
return false;
}
printf("%s\n", buff);
// terminate the string
buff[n] = 0;
char * curr = buff;
// parse the method
METHOD method = UNKNOWN;
if (strncmp(curr, "GET ", 4) == 0)
{
curr += 4;
method = GET;
}
else if (strncmp(curr, "POST ", 5) == 0)
{
curr += 5;
method = POST;
}
else if (write(sockfd, HTTP_400, HTTP_400_LENGTH) < 0)
{
perror("write");
return false;
}
// sanitise the URI
while (*curr == '.' || *curr == '/'){
++curr;
}
if (strlen(curr) > 0) {
if (method == GET)
{
if( strstr(buff, "?start=Start") != NULL ){
/* Handle resetting users when starting a new game */
printf("gameover: %d\n", gameover);
if(gameover == 0){
set_user(sockfd);
} else {
printf("Restarting game, user1: %d, user2: %d\n", user1, user2);
gameover = 0;
}
user_ready(sockfd);
webpage = "html/3_first_turn.html";
} else {
webpage = "html/1_intro.html";
}
// get the size of the file
struct stat st;
stat(webpage, &st);
n = sprintf(buff, HTTP_200_FORMAT, st.st_size);
// send the header first
if (write(sockfd, buff, n) < 0)
{
perror("write"); return false;
}
// send the file
int filefd = open(webpage, O_RDONLY);
do
{
n = sendfile(sockfd, filefd, NULL, 2048);
}
while (n > 0);
if (n < 0)
{
perror("sendfile");
close(filefd);
return false;
}
close(filefd);
}
else if (method == POST)
{
char *username;
int username_length;
long added_length;
long size;
webpage = "html/2_start.html";
// get the size of the file
struct stat st;
if(strstr(buff, "quit=Quit") != NULL){
webpage = "html/7_gameover.html";
stat(webpage, &st);
// Reset User
reset_user(sockfd);
n = sprintf(buff, HTTP_200_FORMAT, st.st_size);
if (write(sockfd, buff, n) < 0)
{
perror("write");
return false;
}
int filefd = open(webpage, O_RDONLY);
n = read(filefd, buff, 2048);
if (n < 0)
{
perror("read");
close(filefd);
return false;
}
close(filefd);
stat(webpage, &st);
if (write(sockfd, buff, st.st_size) < 0)
{
perror("write");
return false;
}
} else if(strstr(buff, "user=") != NULL){
stat(webpage, &st);
username = strstr(buff, "user=") + 5;
username_length = strlen(username);
added_length = username_length + 2;
size = st.st_size + added_length;
n = sprintf(buff, HTTP_200_FORMAT, size);
}
else if(strstr(buff, "guess=Guess") != NULL) {
char *keyword = strstr(buff, "keyword=")+8;
int keyword_length = strlen(keyword); keyword[keyword_length-12] = '\0';
if (sockfd == user1){
/* if other player is ready then accept guesses */
if(user2_start == 1){
webpage = "html/4_accepted.html";
strcpy(user1_guesses[user1_guess_number], keyword);
user1_guess_number++;
/* Check if other play has made the same guess */
for(int i=0; i<user2_guess_number; i++)
{
if(strcmp(user2_guesses[i], keyword) == 0){
reset_game();
webpage = "html/6_endgame.html";
}
}
} else if( gameover == 1){
webpage = "html/6_endgame.html";
} else {
webpage = "html/5_discarded.html";
}
} else if(sockfd == user2){
if(user1_start == 1){
webpage = "html/4_accepted.html";
strcpy(user2_guesses[user2_guess_number], keyword);
user2_guess_number++;
for(int i=0; i<user1_guess_number; i++)
{
if(strcmp(user1_guesses[i], keyword) == 0){
reset_game();
webpage = "html/6_endgame.html";
}
}
} else if( gameover == 1){
webpage = "html/6_endgame.html";
} else {
webpage = "html/5_discarded.html";
}
} else {
webpage = "html/6_endgame.html";
}
stat(webpage, &st);
n = sprintf(buff, HTTP_200_FORMAT, st.st_size);
} else {
printf("\n\n\nerror reading html...\n\n\n");
}
// send the header first
if (write(sockfd, buff, n) < 0)
{
perror("write");
return false;
}
// read the content of the HTML file
int filefd = open(webpage, O_RDONLY);
n = read(filefd, buff, 2048);
if (n < 0)
{
perror("read");
close(filefd);
return false;
}
close(filefd);
if((strlen(username) > 0) && (strstr(buff, "user=") != NULL) ){
// move the trailing part backward
int p1, p2;
for (p1 = size - 1, p2 = p1 - added_length; p1 >= size - 25; --p1, --p2)
buff[p1] = buff[p2];
++p2;
// put the separator
buff[p2++] = ' ';
buff[p2++] = ' ';
// copy the username
strncpy(buff + p2, username, username_length);
if (write(sockfd, buff, size) < 0)
{
perror("write");
return false;
}
} else {
if (write(sockfd, buff, st.st_size) < 0)
{
perror("write");
return false;
}
}
}
else {
// never used, just for completeness
fprintf(stderr, "no other methods supported");
}
// send 404
} else if (write(sockfd, HTTP_404, HTTP_404_LENGTH) < 0)
{
perror("write");
return false;
}
return true;
}
int main(int argc, char * argv[])
{
if (argc < 3)
{
fprintf(stderr, "usage: %s ip port\n", argv[0]);
return 0;
}
// create TCP socket which only accept IPv4
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
{
perror("socket");
exit(EXIT_FAILURE);
}
// reuse the socket if possible
int const reuse = 1;
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(int)) < 0)
{
perror("setsockopt");
exit(EXIT_FAILURE);
}
// create and initialise address we will listen on
struct sockaddr_in serv_addr;
bzero(&serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
// if ip parameter is not specified
serv_addr.sin_addr.s_addr = inet_addr(argv[1]); serv_addr.sin_port = htons(atoi(argv[2]));
// bind address to socket
if (bind(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
perror("bind");
exit(EXIT_FAILURE);
}
// listen on the socket
listen(sockfd, 5);
// initialise an active file descriptors set
fd_set masterfds;
FD_ZERO(&masterfds);
FD_SET(sockfd, &masterfds);
// record the maximum socket number
int maxfd = sockfd;
while (1)
{
// monitor file descriptors
fd_set readfds = masterfds;
if (select(FD_SETSIZE, &readfds, NULL, NULL, NULL) < 0)
{
perror("select");
exit(EXIT_FAILURE);
}
// loop all possible descriptor
for (int i = 0; i <= maxfd; ++i) {
// determine if the current file descriptor is active
if (FD_ISSET(i, &readfds))
{
// create new socket if there is new incoming connection request
if (i == sockfd)
{
struct sockaddr_in cliaddr;
socklen_t clilen = sizeof(cliaddr);
int newsockfd = accept(sockfd, (struct sockaddr *)&cliaddr, &clilen);
if (newsockfd < 0)
perror("accept");
else
{
// add the socket to the set
FD_SET(newsockfd, &masterfds);
// update the maximum tracker
if (newsockfd > maxfd)
maxfd = newsockfd;
// print out the IP and the socket number
char ip[INET_ADDRSTRLEN];
printf(
"new connection from %s on socket %d\n",
// convert to human readable string
inet_ntop(cliaddr.sin_family, &cliaddr.sin_addr, ip, INET_ADDRSTRLEN),
newsockfd
);
}
}
// a request is sent from the client
else if (!handle_http_request(i))
{
close(i);
FD_CLR(i, &masterfds);
}
}
}
}
return 0;}
void reset_game(){
gameover = 1;
user1 = -1;
user2 = -1;
user1_guess_number = 0;
user2_guess_number = 0;
user1_start = 0;
user2_start = 0;
for(int i=0; i<100; i++){
memset(user1_guesses[i], '\0', 100);
memset(user2_guesses[i], '\0', 100);
}
printf("Game reset\n");
}
void reset_user(int sockfd){
if(sockfd == user1){
user1 = -1;
user1_start = 0;
printf("User1 reset\n");
} else if(sockfd == user2){
user2 = -1;
user2_start = 0;
printf("User2 reset\n");
} else {
printf("Sockfd not set for some reason..\n\n");
}
}
void set_user(int sockfd){
if( sockfd == user1 ){
// do nothing
printf("User1 already set\n");
} else if( sockfd == user2 ){
// do nothing
printf("User2 already set\n");
} else if( (user1 == -1) && (sockfd != user2) ){
user1 = sockfd;
printf("User1 set to socket: %d\n", sockfd);
} else if( (user2 == -1) && (sockfd != user1) ){
user2 = sockfd;
printf("User2 set to socket: %d\n", sockfd);
}
}
void user_ready(int sockfd){
if( (sockfd == user1) && (user1_start == 0) ){
user1_start = 1;
printf("User1 ready\n");
} else if( (sockfd == user2) && (user2_start == 0) ){
user2_start = 1;
printf("User2 ready\n");
}
}