【Socket编程】基于TCP协议实现客户端与服务端的通信
前言
由于TCP是面向连接的,所以在创建套接字之后还需要进入监听状态,监听状态下可以获取客户端的请求。获得请求之后,服务器需要接受连接,之后再处理事务。
实现服务端具体步骤
总的来说,TCP服务端主要实现以下步骤:
- 创建一个监听套接字对象,指定使用TCP协议
- 绑定套接字到特定的地址和端口号
- 调用listen方法,监听连接请求
- 接收连接,返回一个新的套接字用于与客户端通信,以及客户端的地址
- 处理请求
- 发送响应
- 本次连接结束,关闭套接字
- 服务器结束,关闭监听套接字
为了便于区分,我们将第一个创建的套接字称为监听套接字,监听套接字只获取连接。后创建的套接字用于处理业务。
实现客户端具体步骤
- 创建套接字
- 使用connect方法连接到服务器
- 发送请求
- 接收响应
- 关闭套接字,结束连接
实现服务端
TcpServer.hpp
该头文件定义了一个服务器类,用于实现上述服务器的各个功能,具体代码如下:
#pragma once
#include <iostream>
#include <string>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fstream>
#include <functional>
#include "InetAddr.hpp"
#include "Log.hpp"
using namespace log_ns;
const static int gport = 8888;
const static int gsockfd = -1;
const static int gblcklog = 8;
using task_t = function<void()>;
class TcpServer
{
private:
public:
TcpServer(uint16_t port = gport)
: _port(port), _listensockfd(gsockfd), _isrunning(false)
{
}
void InitServer()
{
// 1.创建socket,选择TCP协议
_listensockfd = socket(AF_INET, SOCK_STREAM, 0);
if (_listensockfd < 0)
{
LOG(FATAL, "socket create error\n");
exit(1);
}
LOG(FATAL, "listen socket create success,sockfd is %d\n", _listensockfd);
// 创建strcut sockaddr_in
struct sockaddr_in local;
memset(&local, 0, sizeof(local));
local.sin_family = AF_INET;
local.sin_port = htons(_port);
local.sin_addr.s_addr = INADDR_ANY;
// 2. bind
int res = bind(_listensockfd, (struct sockaddr *)&local, sizeof(local));
if (res < 0)
{
LOG(FATAL, "server listen bind failed\n");
exit(1);
}
LOG(FATAL, "server listen bind success\n");
// 3.设置监听状态
if (listen(_listensockfd, gblcklog) < 0)
{
LOG(FATAL, "listen error\n");
exit(1);
}
LOG(INFO, "listen suceess\n");
}
void Loop()
{
_isrunning = true;
while (_isrunning)
{
struct sockaddr_in client;
socklen_t len = sizeof(client);
// 4.获取新连接
int sockfd = accept(_listensockfd, (struct sockaddr *)&client, &len);
if (sockfd < 0)
{
LOG(WARNING, "accept error\n");
continue;
}
InetAddr addr(client);
LOG(INFO, "get a new link,client info:%s,sockfd is %d\n", addr.AddrStr().c_str(), sockfd);
// 处理业务
// v0--简单读取消息
Service(sockfd, addr);
}
_isrunning = false;
}
void Service(int sockfd, InetAddr addr)
{
while (true)
{
// 接收消息
char inbuff[1024];
ssize_t n = read(sockfd, inbuff, sizeof(inbuff) - 1);
if (n > 0)
{
inbuff[n] = 0;
LOG(INFO, "get message from client ,message is %s\n", inbuff);
// 回响
string echo_message = "[server say]# ";
echo_message += inbuff;
write(sockfd, echo_message.c_str(), echo_message.size());
}
else if (n == 0)
{
LOG(INFO, "client %s quit\n", addr.AddrStr().c_str());
break;
}
else
{
LOG(ERROR, "read error: %s\n", addr.AddrStr().c_str());
break;
}
}
close(sockfd);
}
private:
uint16_t _port;
int _listensockfd;
bool _isrunning;
};
TcpServerMain.cpp
该文件定义了服务端对象,执行服务端逻辑
#include "TcpServer.hpp"
#include <iostream>
#include <memory>
int main(int argc, char *argv[])
{
if (argc != 2)
{
std::cerr << "Usage: " << argv[0] << " local-port" << std::endl;
exit(0);
}
uint16_t port = std::stoi(argv[1]);
std::unique_ptr<TcpServer> tcvr = make_unique<TcpServer>(port);
tcvr->InitServer();
tcvr->Loop();
return 0;
}
实现客户端
TcpClientMain.cpp
该文件实现了客户端发送请求的逻辑
#include <iostream>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
if (argc != 3)
{
std::cerr << "Usage : " << argv[0] << " server-ip server-port\n"
<< std::endl;
exit(0);
}
std::string ip = argv[1];
uint16_t port = std::stoi(argv[2]);
// 1.创建sockfd
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
{
std::cerr << "create socket error" << std::endl;
exit(0);
}
struct sockaddr_in peer;
memset(&peer, 0, sizeof(peer));
peer.sin_family = AF_INET;
inet_pton(AF_INET, ip.c_str(), &peer.sin_addr);
peer.sin_port = htons(port);
// 2.连接服务器
int n = connect(sockfd, (struct sockaddr *)&peer, sizeof(peer));
if (n < 0)
{
std::cerr << "connect socket error" << std::endl;
exit(2);
}
// 3.处理业务
while (true)
{
std::string message;
std::cout << "Enter #";
std::getline(std::cin, message);
write(sockfd, message.c_str(), message.size());
char echo_buff[1024];
int res = read(sockfd, echo_buff, sizeof(echo_buff) - 1);
if (res > 0)
{
echo_buff[res] = 0;
std::cout << echo_buff << std::endl;
}
else
{
break;
}
}
close(sockfd);
return 0;
}
运行结果![在这里插入图片描述](https://i-blog.csdnimg.cn/direct/6a68fdace67c4111ba5771c14d169291.png)
原文地址:https://blog.csdn.net/qq_62987647/article/details/140583191
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