chat_application/main.c

#include "message.h"
#include "user.h"
#include "easysock.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>
#include <unistd.h>

#define BUFFER_SIZE 10000
#define MAX_CONNECTIONS 100

int num_of_lines(char* filename);
char* file_to_string(char* filename);
User* create_user_list(char* filename);

int main() {
	struct sockaddr temp_addr;
	socklen_t temp_addrlen;

	fd_set read_fd_set;
	int conn_sockets[MAX_CONNECTIONS] = {-1};
	FD_ZERO(&read_fd_set);
	char buffer[BUFFER_SIZE];
	User* users = create_user_list("user_file.txt");

	struct sockaddr addr_struct;
	int server_sock = create_local(4,'T',"127.0.0.1",30000,&addr_struct);
	conn_sockets[0] = server_sock;

	assert(listen(server_sock,MAX_CONNECTIONS) == 0);

	while (true) {
		FD_ZERO(&read_fd_set);
		for (int i=0; i < MAX_CONNECTIONS; i++) {
			if (conn_sockets[i] > 0) {
				FD_SET(conn_sockets[i],&read_fd_set);
			}
		}

		int num_conns = select(FD_SETSIZE, &read_fd_set, NULL, NULL, NULL);

		if (num_conns > 0) {
			if (FD_ISSET(conn_sockets[0],&read_fd_set)) {
				int client_sock = accept(conn_sockets[0],&temp_addr,&temp_addrlen);
				for (int i=0;i < MAX_CONNECTIONS; i++) {
					if (conn_sockets[i] <= 0) {
						conn_sockets[i] = client_sock;
						break;
					}
				}
			}

			for (int i=1; i < MAX_CONNECTIONS; i++) {
				if (FD_ISSET(conn_sockets[i],&read_fd_set)) {
					int num_bytes_read = recv(conn_sockets[i],buffer,sizeof(buffer),0);
					if (num_bytes_read <= 0) {
						close(conn_sockets[i]);
						conn_sockets[i] = 0;
					} else {
						for (int i=0;i<num_bytes_read;i++) {
							printf("%c",buffer[i]);
						}
					}

					
				}
			}


		}
		


	}

//	Message message = new_message("Hello, this is a text message",users[0],users[1]);



//	printf("Message was: %s\nSentfrom: %s\nSent to: %s\nWith password: %s\nSent at: %s\n",message.text, message.sender.username, message.recipient.username, message.recipient.password, asctime(&message.timeinfo));

	
}


User* create_user_list(char* filename) {

	/* Structure of user file - <username> <password> on every line */

	int num_users = num_of_lines(filename);
        char* file_str = file_to_string(filename);

        char* token = malloc(sizeof(char) * 30);
        User* users = calloc(num_users, sizeof(User));

        token = strtok(file_str," \r\n");
        for (int i=0;i<num_users;i++) {
                users[i].username = token;
                token = strtok(NULL," \r\n");
                users[i].password = token;
                token = strtok(NULL," \r\n");
        }

	return users;

}



char* file_to_string(char* filename) {
	FILE* fp = fopen(filename,"r");

	fseek(fp,0,SEEK_END);
	long file_size = ftell(fp);
	rewind(fp);

	char* buffer = calloc(sizeof(char),file_size+1);

	fread(buffer,1,file_size,fp);

	fclose(fp);

	return buffer;
	
}





/* Finds the number of lines in a file (Which MUST end in a new-line, if the last
   line is to be counted) */

int num_of_lines(char* filename) {

	int num_lines = 0;
	FILE* fp = fopen(filename,"r");
	
	if (fp == NULL) {
		return -1;
	}


	for (int c = getc(fp); c != EOF; c = getc(fp)) {
		if (c == '\n') {
			num_lines++;
		}
	}

	fclose(fp);

	return num_lines;

}