在windows平台构建网络应用,必须了解socket I/O模型。windows提供了选择(select)、异步选择(WSAAsyncSelect)、事件选择(WSAEventSelect)、重叠I /O(overlapped I/O)和完成端口(completion port)。
一、客户端代码
- #include "stdafx.h"
- #include
- #include
- #pragma comment(lib, "ws2_32.lib")
- #define SERVER_ADDRESS "192.168.10.56"
- #define PORT 5150
- #define MSGSIZE 1024
- int main(int argc, char* argv[])
- {
- WSADATA wsaData;
- SOCKET sClient;
- SOCKADDR_IN server;
- char szMessage[MSGSIZE];
- int ret;
-
- WSAStartup(0x0202, &wsaData);
-
- sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-
- memset(&server, 0, sizeof(SOCKADDR_IN));
- server.sin_family = AF_INET;
- server.sin_addr.S_un.S_addr = inet_addr(SERVER_ADDRESS);
- server.sin_port = htons(PORT);
- connect(sClient, (sockaddr*)&server, sizeof(SOCKADDR_IN));
- while (TRUE)
- {
- printf("Send:");
- gets(szMessage);
-
- send(sClient, szMessage, strlen(szMessage), 0);
-
- ret = recv(sClient, szMessage, MSGSIZE, 0);
- szMessage[ret] = '/0';
- printf("Received [%d bytes]: '%s'/n", ret, szMessage);
- }
-
- closesocket(sClient);
- WSACleanup();
- return 0;
- }
#include "stdafx.h"
#include
#include
#pragma comment(lib, "ws2_32.lib")
#define SERVER_ADDRESS "192.168.10.56"
#define PORT 5150
#define MSGSIZE 1024
int main(int argc, char* argv[])
{
WSADATA wsaData;
SOCKET sClient;
SOCKADDR_IN server;
char szMessage[MSGSIZE];
int ret;
// Initialize windows socket library
WSAStartup(0x0202, &wsaData);
// Create client socket
sClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
// Connect to server
memset(&server, 0, sizeof(SOCKADDR_IN));
server.sin_family = AF_INET;
server.sin_addr.S_un.S_addr = inet_addr(SERVER_ADDRESS);
server.sin_port = htons(PORT);
connect(sClient, (sockaddr*)&server, sizeof(SOCKADDR_IN));
while (TRUE)
{
printf("Send:");
gets(szMessage);
// Send message
send(sClient, szMessage, strlen(szMessage), 0);
// Receive message
ret = recv(sClient, szMessage, MSGSIZE, 0);
szMessage[ret] = '/0';
printf("Received [%d bytes]: '%s'/n", ret, szMessage);
}
// Clean up
closesocket(sClient);
WSACleanup();
return 0;
}
这是一个最简单的客户端代码,负责发送数据,然后接受返回。
二、使用select模型的服务器
-
-
-
- #include "stdafx.h"
- #include
- #include
- #define PORT 5150
- #define MSGSIZE 1024
- #pragma comment(lib, "ws2_32.lib")
- int g_iTotalConn = 0;
- SOCKET g_CliSocketArr[FD_SETSIZE];
- DWORD WINAPI WorkerThread(LPVOID lpParam);
- int main(int argc, char* argv[])
- {
- WSADATA wsaData;
- SOCKET sListen, sClient;
- SOCKADDR_IN local, client;
- int iAddrSize = sizeof(SOCKADDR_IN);
- DWORD dwThreadId;
-
- WSAStartup(0x0202, &wsaData);
-
- sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-
- local.sin_family = AF_INET;
- local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
- local.sin_port = htons(PORT);
- bind(sListen, (sockaddr*)&local, sizeof(SOCKADDR_IN));
-
- listen(sListen, 3);
-
- CreateThread(NULL, 0, WorkerThread, NULL, 0, &dwThreadId);
- while (TRUE)
- {
-
- sClient = accept(sListen, (sockaddr*)&client, &iAddrSize);
- printf("Accepted client:%s:%d/n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));
-
- g_CliSocketArr[g_iTotalConn++] = sClient;
- }
- return 0;
- }
- DWORD WINAPI WorkerThread(LPVOID lpParam)
- {
- int i;
- fd_set fdread;
- int ret;
- struct timeval tv = {1, 0};
- char szMessage[MSGSIZE];
- while (TRUE)
- {
- FD_ZERO(&fdread);
- for (i = 0; i < g_iTotalConn; i++)
- {
- FD_SET(g_CliSocketArr[i], &fdread);
- }
-
- ret = select(0, &fdread, NULL, NULL, &tv);
- if (ret == 0)
- {
-
- continue;
- }
- for (i = 0; i < g_iTotalConn; i++)
- {
- if (FD_ISSET(g_CliSocketArr[i], &fdread))
- {
-
- ret = recv(g_CliSocketArr[i], szMessage, MSGSIZE, 0);
- if (ret == 0 || (ret == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET))
- {
-
- printf("Client socket %d closed./n", g_CliSocketArr[i]);
- closesocket(g_CliSocketArr[i]);
- if (i < g_iTotalConn-1)
- {
- g_CliSocketArr[i--] = g_CliSocketArr[--g_iTotalConn];
- }
- }
- else
- {
-
- szMessage[ret] = '/0';
- send(g_CliSocketArr[i], szMessage, strlen(szMessage), 0);
- }
- }
- }
- }
- }
// write by larry
// 2009-8-20
// This is server using select model.
#include "stdafx.h"
#include
#include
#define PORT 5150
#define MSGSIZE 1024
#pragma comment(lib, "ws2_32.lib")
int g_iTotalConn = 0;
SOCKET g_CliSocketArr[FD_SETSIZE];
DWORD WINAPI WorkerThread(LPVOID lpParam);
int main(int argc, char* argv[])
{
WSADATA wsaData;
SOCKET sListen, sClient;
SOCKADDR_IN local, client;
int iAddrSize = sizeof(SOCKADDR_IN);
DWORD dwThreadId;
// Initialize windows socket library
WSAStartup(0x0202, &wsaData);
// Create listening socket
sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
// Bind
local.sin_family = AF_INET;
local.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
local.sin_port = htons(PORT);
bind(sListen, (sockaddr*)&local, sizeof(SOCKADDR_IN));
// Listen
listen(sListen, 3);
// Create worker thread
CreateThread(NULL, 0, WorkerThread, NULL, 0, &dwThreadId);
while (TRUE)
{
// Accept a connection
sClient = accept(sListen, (sockaddr*)&client, &iAddrSize);
printf("Accepted client:%s:%d/n", inet_ntoa(client.sin_addr), ntohs(client.sin_port));
// Add socket to g_CliSocketArr
g_CliSocketArr[g_iTotalConn++] = sClient;
}
return 0;
}
DWORD WINAPI WorkerThread(LPVOID lpParam)
{
int i;
fd_set fdread;
int ret;
struct timeval tv = {1, 0};
char szMessage[MSGSIZE];
while (TRUE)
{
FD_ZERO(&fdread);
for (i = 0; i < g_iTotalConn; i++)
{
FD_SET(g_CliSocketArr[i], &fdread);
}
// We only care read event
ret = select(0, &fdread, NULL, NULL, &tv);
if (ret == 0)
{
// Time expired
continue;
}
for (i = 0; i < g_iTotalConn; i++)
{
if (FD_ISSET(g_CliSocketArr[i], &fdread))
{
// A read event happened on g_CliSocketArr
ret = recv(g_CliSocketArr[i], szMessage, MSGSIZE, 0);
if (ret == 0 || (ret == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET))
{
// Client socket closed
printf("Client socket %d closed./n", g_CliSocketArr[i]);
closesocket(g_CliSocketArr[i]);
if (i < g_iTotalConn-1)
{
g_CliSocketArr[i--] = g_CliSocketArr[--g_iTotalConn];
}
}
else
{
// We reveived a message from client
szMessage[ret] = '/0';
send(g_CliSocketArr[i], szMessage, strlen(szMessage), 0);
}
}
}
}
}
这是异步模型中最简单的一种,服务器端的几个主要流程如下:
1.创建监听套接字,绑定,监听;
2.创建工作者线程;
3.创建一个套接字数组,用来存放当前所有活动的客户端套接字,每accept一个连接就更新一次数组;
4.接受客户端的连接。