今天自己用编写了一个简单的c++服务器客户端程序，注释较详细，在此做个笔记。
windows下socket编程的主要流程可概括如下：初始化ws2_32.dll动态库-->创建套接字-->绑定地址信息-->服务器进行监听/客户端连接服务器-->数据交换-->关闭套接字对象。
服务器端：
1 #include <Winsock2.h>
2 #include <Ws2tcpip.h>
3 #include <iostream>
4
5 #pragma comment(lib, "ws2_32.lib") //socket编程需要引用该库
6
7 using std::cerr;
8 using std::cout;
9 using std::endl;
10
11 const char DEFAULT_PORT[] = "4000";
12 const int RECV_BUF_SIZE = 256;
13
14 //服务器
15 int main() {
16 WSADATA wsa_data; //WSADATA变量,包含windows socket执行的信息
17 int i_result = 0; //接收返回值
18 SOCKET sock_server = INVALID_SOCKET; //创建服务器套接字
19 SOCKET sock_client = INVALID_SOCKET; //创建客户端套接字
20 //addrinfo是getaddrinfo()函数用来保存主机地址信息的结构体
21 addrinfo *result = nullptr; //result是存储地址信息的链表
22 addrinfo hints;
23 //初始化winsock动态库(ws2_32.dll),MAKEWORD(2, 2)用于请求使用winsock2.2版本
24 i_result = WSAStartup(MAKEWORD(2, 2), &wsa_data);
25 if (i_result != 0) {
26 cerr << "WSAStartup() function failed: " << i_result << "\n";
27 system("pause");
28 return 1;
29 }
30 //用0填充内存区域,是ZeroMemory的更安全版本
31 SecureZeroMemory(&hints, sizeof(addrinfo));
32 hints.ai_family = AF_INET;
33 hints.ai_socktype = SOCK_STREAM; //流式套接字用于TCP协议
34 hints.ai_protocol = IPPROTO_TCP;
35 hints.ai_flags = AI_PASSIVE; //socket的地址会被用于bind()函数的调用
36 //确定服务器的地址与端口,将相关信息写入result中
37 i_result = getaddrinfo(nullptr, DEFAULT_PORT, &hints, &result);
38 if (i_result != 0) {
39 cerr << "getaddrinfo() function failed with error: " << WSAGetLastError() << "\n";
40 WSACleanup();
41 system("pause");
42 return 1;
43 }
44 //创建服务器套接字
45 sock_server = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
46 //套接字创建失败
47 if (sock_server == INVALID_SOCKET) {
48 cerr << "socket() function failed with error: " << WSAGetLastError() << "\n";
49 //将getaddrinfo()函数动态分配的addrinfo中的地址信息释放掉
50 freeaddrinfo(result);
51 //释放套接字资源
52 WSACleanup();
53 system("pause");
54 return 1;
55 }
56 //将服务器套接字与地址对象绑定,result->ai_addr是结构体的指针
57 i_result = bind(sock_server, result->ai_addr, static_cast<int>(result->ai_addrlen));
58 //绑定失败
59 if (i_result == SOCKET_ERROR) {
60 cerr << "bind() function failed with error: " << WSAGetLastError() << "\n";
61 freeaddrinfo(result);
62 closesocket(sock_server);
63 WSACleanup();
64 system("pause");
65 return 1;
66 }
67 freeaddrinfo(result);
68 cout << "server started successfully..." << endl;
69 //开始监听
70 cout << "start listening..." << endl;
71 i_result = listen(sock_server, SOMAXCONN);
72 if (i_result == SOCKET_ERROR) {
73 cerr << "listen() function failed with error: " << WSAGetLastError() << "\n";
74 closesocket(sock_server);
75 system("pause");
76 return 1;
77 }
78 //接收客户端请求
79 sock_client = accept(sock_server, nullptr, nullptr);
80 if (sock_client == INVALID_SOCKET) {
81 cerr << "accept() function failed with error: " << WSAGetLastError() << "\n";
82 closesocket(sock_server);
83 WSACleanup();
84 system("pause");
85 return 1;
86 }
87 //接收和发送数据
88 char recv_buf[RECV_BUF_SIZE];
89 int send_result = 0;
90 do {
91 //不可缺少,若不将内存空间清零会输出乱码,这是因为输送过来的信息未必有256个字节
92 SecureZeroMemory(recv_buf, RECV_BUF_SIZE);
93 //标志位一般设置为0
94 i_result = recv(sock_client, recv_buf, RECV_BUF_SIZE, 0);
95 if (i_result > 0) {
96 //exit表示客户端请求断开连接
97 if (strcmp(recv_buf, "exit") == 0) {
98 cout << "client request to close the connection..." << endl;
99 break;
100 }
101 //输出接收的字节数
102 cout << "Bytes received: " << i_result << endl;
103 cout << "message received: " << recv_buf << endl;
104 //向客户端发送接收到的数据
105 send_result = send(sock_client, recv_buf, i_result, 0);
106 if (send_result == SOCKET_ERROR) {
107 cerr << "send() function failed with error: " << WSAGetLastError() << "\n";
108 closesocket(sock_client);
109 WSACleanup();
110 system("pause");
111 return 1;
112 }
113 cout << "Bytes sent: " << send_result << endl;
114 }
115 //i_result的值为0表示连接已经关闭
116 else if (i_result == 0) {
117 cout << "connection closed..." << endl;
118 }
119 else {
120 cerr << "recv() function failed with error: " << WSAGetLastError() << "\n";
121 closesocket(sock_client);
122 WSACleanup();
123 system("pause");
124 return 1;
125 }
126 } while (i_result > 0); //do...while语句后注意要有分号
127 //shutdown()禁用套接字的接收或发送功能
128 i_result = shutdown(sock_client, SD_SEND);
129 if (i_result == SOCKET_ERROR) {
130 cerr << "shutdown() function failed with error: " << WSAGetLastError() << "\n";
131 closesocket(sock_client);
132 WSACleanup();
133 system("pause");
134 return 1;
135 }
136 //关闭套接字
137 i_result = closesocket(sock_server);
138 WSACleanup();
139 cout << "socket closed..." << endl;
140 system("pause");
141 return 0;
142 }
客户端：
1 #include <iostream>
2 #include <WinSock2.h>
3 #include <Ws2tcpip.h>
4
5 #pragma comment(lib, "ws2_32.lib")
6
7 using std::cin;
8 using std::cerr;
9 using std::cout;
10 using std::endl;
11 using std::flush;
12
13 const char DEFAULT_PORT[] = "4000";
14 const int SEND_BUF_SIZE = 256;
15
16 //客户端
17 int main() {
18 WSADATA wsa_data; //WSADATA变量,包含windows socket执行的信息
19 int i_result = 0; //接收返回值
20 SOCKET sock_client = INVALID_SOCKET;
21 addrinfo *result = nullptr, hints;
22 //初始化winsock动态库(ws2_32.dll),MAKEWORD(2, 2)用于请求使用winsock2.2版本
23 i_result = WSAStartup(MAKEWORD(2, 2), &wsa_data);
24 if (i_result != 0) {
25 cerr << "WSAStartup() function failed: " << i_result << "\n";
26 system("pause");
27 return 1;
28 }
29 SecureZeroMemory(&hints, sizeof(hints));
30 hints.ai_family = AF_UNSPEC;
31 hints.ai_socktype = SOCK_STREAM;
32 hints.ai_protocol = IPPROTO_TCP;
33 //
34 i_result = getaddrinfo("127.0.0.1", DEFAULT_PORT, &hints, &result);
35 if (i_result != 0) {
36 cerr << "getaddrinfo() function failed with error: " << WSAGetLastError() << "\n";
37 WSACleanup();
38 system("pause");
39 return 1;
40 }
41 //创建套接字
42 sock_client = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
43 if (sock_client == INVALID_SOCKET) {
44 cerr << "socket() function failed with error: " << WSAGetLastError() << "\n";
45 WSACleanup();
46 system("pause");
47 return 1;
48 }
49 //连接服务器
50 i_result = connect(sock_client, result->ai_addr, result->ai_addrlen);
51 if (i_result == SOCKET_ERROR) {
52 cerr << "connect() function failed with error: " << WSAGetLastError() << "\n";
53 WSACleanup();
54 system("pause");
55 return 1;
56 }
57 cout << "connect server successfully..." << endl;
58 //
59 freeaddrinfo(result);
60 //
61 char send_buf[SEND_BUF_SIZE];
62 int recv_result = 0;
63 //SecureZeroMemory(send_buf, SEND_BUF_SIZE);
64 do {
65 cout << "enter the message that you want to send: " << flush;
66 cin >> send_buf;
67 i_result = send(sock_client, send_buf, static_cast<int>(strlen(send_buf)), 0);
68 if (i_result == SOCKET_ERROR) {
69 cerr << "send() function failed with error: " << WSAGetLastError() << "\n";
70 closesocket(sock_client);
71 WSACleanup();
72 system("pause");
73 return 1;
74 }
75 cout << "Bytes sent: " << i_result << endl;
76 //接收服务器返回的数据
77 recv_result = recv(sock_client, send_buf, SEND_BUF_SIZE, 0);
78 if (recv_result > 0) {
79 cout << "feedback from server: " << send_buf << endl;
80 }
81 else if (recv_result == 0) {
82 cout << "connection closed..." << endl;
83 }
84 else {
85 cerr << "recv() function failed with error: " << WSAGetLastError() << "\n";
86 closesocket(sock_client);
87 WSACleanup();
88 system("pause");
89 return 1;
90 }
91 } while (recv_result > 0);
92 //
93 i_result = shutdown(sock_client, SD_SEND);
94 if (i_result == SOCKET_ERROR) {
95 cerr << "shutdown() function failed with error: " << WSAGetLastError() << "\n";
96 closesocket(sock_client);
97 WSACleanup();
98 system("pause");
99 return 1;
100 }
101 closesocket(sock_client);
102 WSACleanup();
103 cout << "socket closed..." << endl;
104 system("pause");
105 return 0;
106 }
时间： 2024-10-20 05:12:34