Linux中C/Socket编程中的聊天室 [英] Chatroom in C / Socket programming in Linux

问题描述

我有一个简单的服务器和客户端C代码，可以使用线程(pthread库)为多客户端创建一个聊天室.我一直遇到的问题是，我无法想到一种使服务器将客户端通过套接字发送的每条消息写入所有其他客户端的方法.我在这里读过其他类似的文章，这很无奈.请帮我，我需要上学去做.我将立即发送两个验证码.

I have a simple server and client C code to do a chatroom for multiclients using threads (pthread library). The problem I've been having is that I can't think a way of making the server write every message that a client sends over the socket into all other clients. I've read other similar posts in here and it was helpless. Please help me I need to do this for school. I'll send both codes right away.

Server.c:

#include<stdio.h>
#include<string.h>    //strlen
#include<stdlib.h>    //strlen
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h>    //write

#include<pthread.h> //for threading , link with lpthread

void *connection_handler(void *);


int main(int argc , char *argv[])
{
    int socket_desc , new_socket , c , *new_sock;
    struct sockaddr_in server , client;
    char *message;

    //Create socket
    socket_desc = socket(AF_INET , SOCK_STREAM , 0);
    if (socket_desc == -1)
    {
        printf("Could not create socket");
    }

    //Prepare the sockaddr_in structure
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons( 8888 );

    //Bind
    if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
    {
        puts("bind failed");
        return 1;
    }
    puts("bind done");

    //Listen
    listen(socket_desc , 3);

    //Accept and incoming connection
    puts("Waiting for incoming connections...");
    c = sizeof(struct sockaddr_in);
    while( (new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c)) )
    {
        puts("Connection accepted");

        pthread_t sniffer_thread;
        new_sock = malloc(1);
        *new_sock = new_socket;

        if( pthread_create( &sniffer_thread , NULL ,  connection_handler , (void*) new_sock) < 0)
        {
            perror("could not create thread");
            return 1;
        }

        //Now join the thread , so that we dont terminate before the thread
        //pthread_join( sniffer_thread , NULL);
        puts("Handler assigned");
    }

    if (new_socket<0)
    {
        perror("accept failed");
        return 1;
    }

    return 0;
}

/*
 * This will handle connection for each client
 * */
void *connection_handler(void *socket_desc)
{
    //Get the socket descriptor
    int sock = *(int*)socket_desc;
    int read_size;
    char *message , client_message[2000];


    //Receive a message from client
    while( (read_size = recv(sock , client_message , 2000 , 0)) > 0 )
    {
        //Send the message back to client
        write(sock , client_message , strlen(client_message));
    }

    if(read_size == 0)
    {
        puts("Client disconnected");
        fflush(stdout);
    }
    else if(read_size == -1)
    {
        perror("recv failed");
    }

    //Free the socket pointer
    free(socket_desc);

    return 0;
}

Client.c

#include<stdio.h> //printf
#include<string.h>    //strlen
#include<sys/socket.h>    //socket
#include<arpa/inet.h> //inet_addr

int main(int argc , char *argv[])
{
    int sock;
    struct sockaddr_in server;
    char message[1000] , server_reply[2000];

    //Create socket
    sock = socket(AF_INET , SOCK_STREAM , 0);
    if (sock == -1)
    {
        printf("Could not create socket");
    }
    puts("Socket created");

    server.sin_addr.s_addr = inet_addr("127.0.0.1");
    server.sin_family = AF_INET;
    server.sin_port = htons( 8888 );

    //Connect to remote server
    if (connect(sock , (struct sockaddr *)&server , sizeof(server)) < 0)
    {
        perror("connect failed. Error");
        return 1;
    }

    puts("Connected\n");
    puts("Bienvenido al Chatroom, puedes empezar a escribir en la sala!");

    //keep communicating with server
    while(1)
    {

        printf("Enter message: ");
    fgets(message, sizeof(message),stdin);
        //scanf("%s" , message);

        //Send some data
        if( send(sock , message , strlen(message) , 0) < 0)
        {
            puts("Send failed");
            return 1;
        }

        //Receive a reply from the server
        if( recv(sock , server_reply , 2000 , 0) < 0)
        {
            puts("recv failed");
            break;
        }

    printf("Server Reply: %s\n", server_reply);
    server_reply[0]='\0'; 
    }

    close(sock);
    return 0;
}

这些程序非常简单，客户端发送用户在控制台中写的内容，服务器发送相同的消息.我只需要服务器向连接的每个线程(客户端)发送相同的消息(不仅是发送原始消息的线程).

These programs are very simple, the client sends what the user writes in console and the server send the same message back. I just need the server to send the same message to every thread (client) connected (not only the one who sent the original message).

我知道所有人都需要这个护理，但是如果可以的话，我很乐意得到一些帮助:)

I know this is long for anyone to care, but if you can, I'll be glad to get some help :)

推荐答案

您需要一个由互斥锁保护的所有客户端的全局表.当新的客户端连接时，将它们添加到客户端的全局表中.当客户端断开连接时，请将其从全局表中删除.

You need a global table of all clients, protected by a mutex. When a new client connects, add them to the global table of clients. When a client disconnects, remove them from the global table.

当客户端发送消息时，获取并锁定全局表.将消息发送给所有客户端(如果您不想将消息回显到源，则发送消息的客户端除外).

When a client sends a message, acquire the lock on the global table and traverse it. Send the message to all clients (other than the one that sent the message, if you don't want to echo a message back to its source).

这是对真实服务器的工作方式的过度简化.但这足以让您入门.

This is a gross oversimplification of how real servers do it. But it should be enough to get you started.

这篇关于Linux中C/Socket编程中的聊天室的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！