TCP並發服務器簡單示例

並發服務器的思想是每一個客戶的請求並不由服務器直接處理，而是由服務器創建一個子進程來處理

1. 服務器端

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <sys/wait.h>
#include <netdb.h>
#include <pthread.h>

//線程執行函數負責讀寫
void *thr_fn(void *arg)
{
    int size, j;
    char recv_buf[1024];
    int *parg = (int *)arg;
    int new_fd = *parg;
    
    printf("new_fd = %d\n", new_fd);
    
    while((size=read(new_fd, recv_buf, 1024)) > 0)
    {
        if(recv_buf[0]=='@')
            break;
        printf("Message from client(%d): %s\n",size,recv_buf);
        for(j = 0; j < size; j++)
            recv_buf[j] = toupper(recv_buf[j]);
        write(new_fd, recv_buf, size);
    }
    
    close(new_fd);
    
    return 0;
}


int main(int argc,char *argv[])
{
    socklen_t clt_addr_len;
    int listen_fd;
    int com_fd;
    int ret;
    int i;
    static char recv_buf[1024];
    int len;
    int port;
    pthread_t tid;

    struct sockaddr_in clt_addr;
    struct sockaddr_in srv_addr;

    //服務器端運行時要給出端口信息，該端口為監聽端口 
    if(argc != 2)
    {
        printf("Usage:%s port\n", argv[0]);
        return 1;
    }

    //獲得輸入的端口 
    port = atoi(argv[1]);

    //創建套接字用於服務器的監聽 
    listen_fd = socket(PF_INET, SOCK_STREAM, 0);
    if(listen_fd < 0)
    {
        perror("cannot create listening socket");
        return 1;
    }

    //填充關於服務器的套節字信息
    memset(&srv_addr, 0, sizeof(srv_addr));
    
    srv_addr.sin_family = AF_INET;
    srv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    srv_addr.sin_port = htons(port);


    //將服務器和套節字綁定
    ret = bind(listen_fd, (struct sockaddr *)&srv_addr, sizeof(srv_addr));
    if(ret == -1)
    {
        perror("cannot bind server socket");
        close(listen_fd);
        return 1;
    }

    //監聽指定端口，連接5個客戶端 
    ret = listen(listen_fd, 5);
    if(ret == -1)
    {
        perror("cannot listen the client connect request");
        close(listen_fd);
        return 1;
    }
    //對每個連接來的客戶端創建一個線程，單獨與其進行通信 
    //首先調用read函數讀取客戶端發送來的信息 
    //將其轉換成大寫后發送回客戶端 
    //當輸入“@”時，程序退出 
    while(1)
    {
        len = sizeof(clt_addr);
        
        com_fd = accept(listen_fd, (struct sockaddr *)&clt_addr, &len);
        if(com_fd < 0)
        {
            if(errno == EINTR)
            {
                continue;
            }
            else
            {
                perror("cannot accept client connect request");
                close(listen_fd);
                
                return 1;
            }
        }
        
        printf("com_fd = %d\n", com_fd);//打印建立連接的客戶端產生的套節字
        if((pthread_create(&tid, NULL, thr_fn, &com_fd)) == -1)
        {
            perror("pthread_create error");
            close(listen_fd);
            close(com_fd);
            
            return 1;
        }
    }
    
    return 0;
}

 

2. 客戶端

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netdb.h>
#include <unistd.h>

int main(int argc,char *argv[])
{
    int connect_fd;
    int ret;
    char snd_buf[1024];
    int i;
    int port;
    int len;

    static struct sockaddr_in srv_addr;

    //客戶端運行需要給出具體的連接地址和端口 
    if(argc != 3)
    {
        printf("Usage: %s server_ip_address port\n",argv[0]);
        return 1;
    }

    //獲得輸入的端口
    port = atoi(argv[2]);

    //創建套節字用於客戶端的連接
    connect_fd = socket(PF_INET,SOCK_STREAM,0);
    if(connect_fd < 0)
    {
        perror("cannot create communication socket");
        return 1;
    }

    //填充關於服務器的套節字信息
    memset(&srv_addr, 0, sizeof(srv_addr));
    
    srv_addr.sin_family = AF_INET;
    srv_addr.sin_addr.s_addr = inet_addr(argv[1]);
    srv_addr.sin_port = htons(port);

    //連接指定的服務器 
    ret = connect(connect_fd, (struct sockaddr *)&srv_addr, sizeof(srv_addr));
    if(ret == -1)
    {
        perror("cannot connect to the server");
        close(connect_fd);
        return 1;
    }

    memset(snd_buf, 0, 1024);
    //用戶輸入信息后，程序將輸入的信息通過套接字發送給服務器 
    //然后調用read函數從服務器中讀取發送來的信息 
    //當輸入“@”時，程序退出 
    while(1)
    {
        write(STDOUT_FILENO, "input message:", 14);
        len = read(STDIN_FILENO, snd_buf, 1024);
        if(len > 0)
            write(connect_fd, snd_buf, len);
        len = read(connect_fd, snd_buf, len);
        if(len > 0)
            printf("Message form server: %s\n", snd_buf);
        if(snd_buf[0] == '@')
            break;
    }
    
    close(connect_fd);
    
    return 0;
}