使用异步命名管道通信的实例

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  
#include 
#include 
#include 

#define PIPE_TIMEOUT 5000
#define BUFSIZE 4096
#define MAX_USERNAME_LEN 100
#define MAX_PASSWORD_LEN 100

typedef 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 attribute
        TRUE,    // 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 attributes
    if (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  
#include 
#include 
#include 

#define BUFSIZE 512

typedef 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 attributes
            OPEN_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");
    _getch();

    CloseHandle(hPipe);

    return 0;
}

测试结果

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发布于：2024.02.08，更新于：2024.02.08.