使用异步命名管道通信的实例-编程知识

记录一个使用异步命名管道通信的实例。代码参考了 MSDN 的文档：使用完成例程的命名管道服务器 - Win32 apps | Microsoft Learn。

服务端代码

#include <windows.h> 
#include <stdio.h>
#include <tchar.h>
#include <strsafe.h>#define PIPE_TIMEOUT 5000
#define BUFSIZE 4096
#define MAX_USERNAME_LEN 100
#define MAX_PASSWORD_LEN 100typedef struct
{OVERLAPPED oOverlap;HANDLE hPipeInst;struct Message {TCHAR username[MAX_USERNAME_LEN];TCHAR password[MAX_PASSWORD_LEN];TCHAR request[BUFSIZE];} message;DWORD cbRead;TCHAR chReply[BUFSIZE];DWORD cbToWrite;
} PIPEINST, * LPPIPEINST;VOID DisconnectAndClose(LPPIPEINST);
BOOL CreateAndConnectInstance(LPOVERLAPPED);
BOOL ConnectToNewClient(HANDLE, LPOVERLAPPED);
VOID GetAnswerToRequest(LPPIPEINST);VOID WINAPI CompletedWriteRoutine(DWORD, DWORD, LPOVERLAPPED);
VOID WINAPI CompletedReadRoutine(DWORD, DWORD, LPOVERLAPPED);HANDLE hPipe;int _tmain(VOID)
{HANDLE hConnectEvent;OVERLAPPED oConnect;LPPIPEINST lpPipeInst;DWORD dwWait, cbRet;BOOL fSuccess, fPendingIO;// Create one event object for the connect operation. hConnectEvent = CreateEvent(NULL,    // default security attributeTRUE,    // manual reset event TRUE,    // initial state = signaled NULL);   // unnamed event object if (hConnectEvent == NULL){printf("CreateEvent failed with %d.\n", GetLastError());return 0;}oConnect.hEvent = hConnectEvent;// Call a subroutine to create one instance, and wait for // the client to connect. fPendingIO = CreateAndConnectInstance(&oConnect);while (1){// Wait for a client to connect, or for a read or write // operation to be completed, which causes a completion // routine to be queued for execution. dwWait = WaitForSingleObjectEx(hConnectEvent,  // event object to wait for INFINITE,       // waits indefinitely TRUE);          // alertable wait enabled switch (dwWait){// The wait conditions are satisfied by a completed connect // operation. case 0:// If an operation is pending, get the result of the // connect operation. if (fPendingIO){fSuccess = GetOverlappedResult(hPipe,     // pipe handle &oConnect, // OVERLAPPED structure &cbRet,    // bytes transferred FALSE);    // does not wait if (!fSuccess){printf("ConnectNamedPipe (%d)\n", GetLastError());return 0;}}// Allocate storage for this instance. lpPipeInst = (LPPIPEINST)GlobalAlloc(GPTR, sizeof(PIPEINST));if (lpPipeInst == NULL){printf("GlobalAlloc failed (%d)\n", GetLastError());return 0;}lpPipeInst->hPipeInst = hPipe;// Start the read operation for this client. // Note that this same routine is later used as a // completion routine after a write operation. lpPipeInst->cbToWrite = 0;CompletedWriteRoutine(0, 0, (LPOVERLAPPED)lpPipeInst);// Create new pipe instance for the next client. fPendingIO = CreateAndConnectInstance(&oConnect);break;// The wait is satisfied by a completed read or write // operation. This allows the system to execute the // completion routine. case WAIT_IO_COMPLETION:break;// An error occurred in the wait function. default:{printf("WaitForSingleObjectEx (%d)\n", GetLastError());return 0;}}}return 0;
}// CompletedWriteRoutine(DWORD, DWORD, LPOVERLAPPED) 
// This routine is called as a completion routine after writing to 
// the pipe, or when a new client has connected to a pipe instance.
// It starts another read operation. VOID WINAPI CompletedWriteRoutine(DWORD dwErr, DWORD cbWritten,LPOVERLAPPED lpOverLap)
{LPPIPEINST lpPipeInst;BOOL fRead = FALSE;// lpOverlap points to storage for this instance. lpPipeInst = (LPPIPEINST)lpOverLap;// The write operation has finished, so read the next request (if // there is no error). if ((dwErr == 0) && (cbWritten == lpPipeInst->cbToWrite))fRead = ReadFileEx(lpPipeInst->hPipeInst,&lpPipeInst->message,sizeof(lpPipeInst->message),(LPOVERLAPPED)lpPipeInst,(LPOVERLAPPED_COMPLETION_ROUTINE)CompletedReadRoutine);// Disconnect if an error occurred. if (!fRead)DisconnectAndClose(lpPipeInst);
}// CompletedReadRoutine(DWORD, DWORD, LPOVERLAPPED) 
// This routine is called as an I/O completion routine after reading 
// a request from the client. It gets data and writes it to the pipe. VOID WINAPI CompletedReadRoutine(DWORD dwErr, DWORD cbBytesRead,LPOVERLAPPED lpOverLap)
{LPPIPEINST lpPipeInst;BOOL fWrite = FALSE;// lpOverlap points to storage for this instance. lpPipeInst = (LPPIPEINST)lpOverLap;// The read operation has finished, so write a response (if no // error occurred). if ((dwErr == 0) && (cbBytesRead != 0)){GetAnswerToRequest(lpPipeInst);if (lpPipeInst->cbToWrite == 0){return;}fWrite = WriteFileEx(lpPipeInst->hPipeInst,lpPipeInst->chReply,lpPipeInst->cbToWrite,(LPOVERLAPPED)lpPipeInst,(LPOVERLAPPED_COMPLETION_ROUTINE)CompletedWriteRoutine);}// Disconnect if an error occurred. if (!fWrite)DisconnectAndClose(lpPipeInst);
}// DisconnectAndClose(LPPIPEINST) 
// This routine is called when an error occurs or the client closes 
// its handle to the pipe. VOID DisconnectAndClose(LPPIPEINST lpPipeInst)
{// Disconnect the pipe instance. if (!DisconnectNamedPipe(lpPipeInst->hPipeInst)){printf("DisconnectNamedPipe failed with %d.\n", GetLastError());}// Close the handle to the pipe instance. CloseHandle(lpPipeInst->hPipeInst);// Release the storage for the pipe instance. if (lpPipeInst != NULL)GlobalFree(lpPipeInst);
}// CreateAndConnectInstance(LPOVERLAPPED) 
// This function creates a pipe instance and connects to the client. 
// It returns TRUE if the connect operation is pending, and FALSE if 
// the connection has been completed. BOOL CreateAndConnectInstance(LPOVERLAPPED lpoOverlap)
{LPCTSTR lpszPipename = L"\\\\.\\pipe\\mynamedpipe";hPipe = CreateNamedPipe(lpszPipename,             // pipe name PIPE_ACCESS_DUPLEX |      // read/write access FILE_FLAG_OVERLAPPED,     // overlapped mode PIPE_TYPE_MESSAGE |       // message-type pipe PIPE_READMODE_MESSAGE |   // message read mode PIPE_WAIT,                // blocking mode PIPE_UNLIMITED_INSTANCES, // unlimited instances BUFSIZE * sizeof(TCHAR),    // output buffer size BUFSIZE * sizeof(TCHAR),    // input buffer size PIPE_TIMEOUT,             // client time-out NULL);                    // default security attributesif (hPipe == INVALID_HANDLE_VALUE){printf("CreateNamedPipe failed with %d.\n", GetLastError());return 0;}// Call a subroutine to connect to the new client. return ConnectToNewClient(hPipe, lpoOverlap);
}BOOL ConnectToNewClient(HANDLE hPipe, LPOVERLAPPED lpo)
{BOOL fConnected, fPendingIO = FALSE;// Start an overlapped connection for this pipe instance. fConnected = ConnectNamedPipe(hPipe, lpo);// Overlapped ConnectNamedPipe should return zero. if (fConnected){printf("ConnectNamedPipe failed with %d.\n", GetLastError());return 0;}switch (GetLastError()){// The overlapped connection in progress. case ERROR_IO_PENDING:fPendingIO = TRUE;break;// Client is already connected, so signal an event. case ERROR_PIPE_CONNECTED:if (SetEvent(lpo->hEvent))break;// If an error occurs during the connect operation... default:{printf("ConnectNamedPipe failed with %d.\n", GetLastError());return 0;}}return fPendingIO;
}BOOL AuthenticateClient(LPPIPEINST lpPipeInst) {// 硬编码的用户名和密码列表const TCHAR* validUsernames[] = { TEXT("WMsgClientName") };const TCHAR* validPasswords[] = { TEXT("WMsgClientPassword") };// 从 lpPipeInst 中获取客户端发送的身份验证信息（例如，用户名和密码）TCHAR username[MAX_USERNAME_LEN];TCHAR password[MAX_PASSWORD_LEN];TCHAR request[BUFSIZE];// 解析客户端发送的身份验证信息lstrcpy(username, lpPipeInst->message.username);lstrcpy(password, lpPipeInst->message.password);lstrcpy(request, lpPipeInst->message.request);// 检查用户名和密码是否在有效的用户名和密码列表中for (int i = 0; i < sizeof(validUsernames) / sizeof(validUsernames[0]); i++) {if (_tcscmp(username, validUsernames[i]) == 0 && _tcscmp(password, validPasswords[i]) == 0) {// 用户名和密码匹配，身份验证成功// 将余下的请求部分复制到 lpPipeInst->chRequest 中lstrcpy(lpPipeInst->message.request, request);// 设置请求长度lpPipeInst->cbRead = (lstrlen(lpPipeInst->message.request) + 1) * sizeof(TCHAR);return TRUE;}}// 如果用户名和密码不匹配任何有效的用户名和密码，身份验证失败_tprintf(TEXT("Invalid authentication.\n"));return FALSE;
}VOID GetAnswerToRequest(LPPIPEINST pipe)
{_tprintf(TEXT("ClientMsg:[0x%I64X] %s\n"), (UINT64)pipe->hPipeInst, pipe->message.request);// 验证客户端身份if (!AuthenticateClient(pipe)){pipe->cbToWrite = 0;DisconnectAndClose(pipe);return;}_tprintf(TEXT("Client authentication completed.\n"));// 根据客户端发送的不同消息生成不同的回复if (_tcscmp(pipe->message.request, TEXT("Request1")) == 0){StringCchCopy(pipe->chReply, BUFSIZE, TEXT("Response to Request1"));}else if (_tcscmp(pipe->message.request, TEXT("Request2")) == 0){StringCchCopy(pipe->chReply, BUFSIZE, TEXT("Response to Request2"));}else{StringCchCopy(pipe->chReply, BUFSIZE, TEXT("Default answer from server"));}pipe->cbToWrite = (lstrlen(pipe->chReply) + 1) * sizeof(TCHAR);
}

客户端代码

#include <windows.h> 
#include <stdio.h>
#include <conio.h>
#include <tchar.h>#define BUFSIZE 512typedef struct
{TCHAR username[100];TCHAR password[100];TCHAR request[BUFSIZE];
} Message;int _tmain(int argc, TCHAR* argv[])
{HANDLE hPipe;Message message;BOOL   fSuccess = FALSE;DWORD  cbRead, cbToWrite, cbWritten, dwMode;LPCTSTR lpszPipename = L"\\\\.\\pipe\\mynamedpipe";// 初始化结构体信息_tcscpy_s(message.username, _T("WMsgClientName"));_tcscpy_s(message.password, _T("WMsgClientPassword"));if (argc > 1)_tcscpy_s(message.request, argv[1]);else_tcscpy_s(message.request, _T("Default request from client."));// 尝试打开命名管道while (1){hPipe = CreateFile(lpszPipename,   // pipe name GENERIC_READ |  // read and write access GENERIC_WRITE,0,              // no sharing NULL,           // default security attributesOPEN_EXISTING,  // opens existing pipe 0,              // default attributes NULL);          // no template file // 如果管道句柄有效，则退出循环if (hPipe != INVALID_HANDLE_VALUE)break;// 如果错误不是 ERROR_PIPE_BUSY，则退出程序if (GetLastError() != ERROR_PIPE_BUSY){_tprintf(TEXT("Could not open pipe. GLE=%d\n"), GetLastError());return -1;}// 如果所有管道实例都在忙，则等待 20 秒if (!WaitNamedPipe(lpszPipename, 20000)){printf("Could not open pipe: 20 second wait timed out.");return -1;}}// 设置管道模式为消息读取模式dwMode = PIPE_READMODE_MESSAGE;fSuccess = SetNamedPipeHandleState(hPipe,    // 管道句柄 &dwMode,  // 新的管道模式 NULL,     // 不设置最大字节数 NULL);    // 不设置最大时间 if (!fSuccess){_tprintf(TEXT("SetNamedPipeHandleState failed. GLE=%d\n"), GetLastError());return -1;}// 向管道服务器发送消息cbToWrite = sizeof(message);_tprintf(TEXT("Sending %d byte message: \"%s\"\n"), cbToWrite, message.request);fSuccess = WriteFile(hPipe,                  // 管道句柄 &message,               // 消息 cbToWrite,              // 消息长度 &cbWritten,             // 写入的字节数 NULL);                  // 不使用重叠if (!fSuccess){_tprintf(TEXT("WriteFile to pipe failed. GLE=%d\n"), GetLastError());return -1;}printf("\nMessage sent to server, receiving reply as follows:\n");// 从管道读取服务器的回复fSuccess = ReadFile(hPipe,    // 管道句柄 message.request, // 用于接收回复的缓冲区 BUFSIZE * sizeof(TCHAR),  // 缓冲区大小 &cbRead,  // 读取的字节数 NULL);    // 不使用重叠if (!fSuccess){_tprintf(TEXT("ReadFile from pipe failed. GLE=%d\n"), GetLastError());return -1;}_tprintf(TEXT("Server's reply: \"%s\"\n"), message.request);printf("\n<End of message, press ENTER to terminate connection and exit>");_getch();CloseHandle(hPipe);return 0;
}