Windows进程间通信—命名管道

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命名管道是通过网络来完成进程间的通信,它屏蔽了底层的网络协议细节。我们在不了解网络协议的情况下,也可以利用命名管道来实现进程间的通信。与Socket网络通信相比,命名管道不再需要编写身份验证的代码。将命名管道作为一种网络编程方案时,它实际上建立了一个C/S通信体系,并在其中可靠的传输数据。命名管道服务器和客户机的区别在于:服务器是唯一一个有权创建命名管道的进程,也只有它能接受管道客户机的连接请求。而客户机只能同一个现成的命名管道服务器建立连接。命名管道服务器只能在WindowsNT或Windows2000上创建,不过可以是客户机。命名管道提供了两种基本通信模式,字节模式和消息模式。在字节模式中,数据以一个连续的字节流的形式在客户机和服务器之间流动。而在消息模式中,客户机和服务器则通过一系列不连续的数据单位进行数据的收发,每次在管道上发出一条消息后,它必须作为一条完整的消息读入。

服务端代码流程:

1、创建命名管道:CreateNamedPipe

2、等待客户端连接:ConnectNamedPipe

3、读取客户端请求数据:ReadFile

4、向客户端回复数据:WriteFile

5、关闭连接:DisconnectNamedPipe

6、关闭管道:CloseHandle

#include "stdafx.h"  
#include <windows.h>  
#include <strsafe.h>  
  
#define BUFSIZE 4096  
  
DWORD WINAPI InstanceThread(LPVOID);   
VOID GetAnswerToRequest(LPTSTR, LPTSTR, LPDWORD);   
  
int _tmain(VOID)   
{   
    BOOL fConnected;   
    DWORD dwThreadId;   
    HANDLE hPipe, hThread;   
    LPTSTR lpszPipename = TEXT("\\\\\\\\.\\\\pipe\\\\mynamedpipe");   
  
    // The main loop creates an instance of the named pipe and   
    // then waits for a client to connect to it. When the client   
    // connects, a thread is created to handle communications   
    // with that client, and the loop is repeated.   
  
    for (;;)   
    {   
        hPipe = CreateNamedPipe(   
            lpszPipename,             // pipe name   
            PIPE_ACCESS_DUPLEX,       // read/write access   
            PIPE_TYPE_MESSAGE |       // message type pipe   
            PIPE_READMODE_MESSAGE |   // message-read mode   
            PIPE_WAIT,                // blocking mode   
            PIPE_UNLIMITED_INSTANCES, // max. instances    
            BUFSIZE,                  // output buffer size   
            BUFSIZE,                  // input buffer size   
            0,                        // client time-out   
            NULL);                    // default security attribute   
  
        if (hPipe == INVALID_HANDLE_VALUE)   
        {  
            printf("CreatePipe failed");   
            return 0;  
        }  
  
        // Wait for the client to connect; if it succeeds,   
        // the function returns a nonzero value. If the function  
        // returns zero, GetLastError returns ERROR_PIPE_CONNECTED.   
  
        fConnected = ConnectNamedPipe(hPipe, NULL) ? TRUE : (GetLastError() == ERROR_PIPE_CONNECTED);   
  
        if (fConnected)   
        {   
            // Create a thread for this client.   
            hThread = CreateThread(   
                NULL,              // no security attribute   
                0,                 // default stack size   
                InstanceThread,    // thread proc  
                (LPVOID) hPipe,    // thread parameter   
                0,                 // not suspended   
                &dwThreadId);      // returns thread ID   
  
            if (hThread == NULL)   
            {  
                printf("CreateThread failed");   
                return 0;  
            }  
            else CloseHandle(hThread);   
        }   
        else  
        {  
            // The client could not connect, so close the pipe.   
            CloseHandle(hPipe);   
        }  
    }   
    return 1;   
}   
  
DWORD WINAPI InstanceThread(LPVOID lpvParam)   
{   
    TCHAR chRequest[BUFSIZE];   
    TCHAR chReply[BUFSIZE];   
    DWORD cbBytesRead, cbReplyBytes, cbWritten;   
    BOOL fSuccess;   
    HANDLE hPipe;   
  
    // The thread\'s parameter is a handle to a pipe instance.   
  
    hPipe = (HANDLE) lpvParam;   
  
    while (1)   
    {   
        // Read client requests from the pipe.   
        fSuccess = ReadFile(   
            hPipe,        // handle to pipe   
            chRequest,    // buffer to receive data   
            BUFSIZE*sizeof(TCHAR), // size of buffer   
            &cbBytesRead, // number of bytes read   
            NULL);        // not overlapped I/O   
  
        if (! fSuccess || cbBytesRead == 0)   
            break;   
        printf((const char*)chRequest);  
  
        GetAnswerToRequest(chRequest, chReply, &cbReplyBytes);   
  
        // Write the reply to the pipe.   
        fSuccess = WriteFile(   
            hPipe,        // handle to pipe   
            chReply,      // buffer to write from   
            cbReplyBytes, // number of bytes to write   
            &cbWritten,   // number of bytes written   
            NULL);        // not overlapped I/O   
  
        if (! fSuccess || cbReplyBytes != cbWritten) break;   
    }   
  
    // Flush the pipe to allow the client to read the pipe\'s contents   
    // before disconnecting. Then disconnect the pipe, and close the   
    // handle to this pipe instance.   
  
    FlushFileBuffers(hPipe);   
    DisconnectNamedPipe(hPipe);   
    CloseHandle(hPipe);   
  
    return 1;  
}  
  
VOID GetAnswerToRequest(LPTSTR chRequest,   
                        LPTSTR chReply, LPDWORD pchBytes)  
{  
    _tprintf( TEXT("%s\\n"), chRequest );  
    StringCchCopy( chReply, BUFSIZE, TEXT("Default answer from server") );  
    *pchBytes = (lstrlen(chReply)+1)*sizeof(TCHAR);  
}  
/* 何问起 hovertree.com */

客户端代码流程:

1、打开命名管道:CreateFile

2、等待服务端响应:WaitNamedPipe

3、切换管道为读模式:SetNamedPipeHandleState

4、向服务端发数据:WriteFile

5、读服务端返回的数据:ReadFile

6、关闭管道:CloseHandle

#include "stdafx.h"  
#include <windows.h>  
#include <conio.h>  
  
  
#define BUFSIZE 512  
  
int _tmain(int argc, TCHAR *argv[])   
{   
    HANDLE hPipe;   
    LPTSTR lpvMessage=TEXT("Default message from client");   
    TCHAR chBuf[BUFSIZE];   
    BOOL fSuccess;   
    DWORD cbRead, cbWritten, dwMode;   
    LPTSTR lpszPipename = TEXT("\\\\\\\\.\\\\pipe\\\\mynamedpipe");   
  
    if( argc > 1 )  
        lpvMessage = argv[1];  
  
    // Try to open a named pipe; wait for it, if necessary.   
  
    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   
  
        // Break if the pipe handle is valid.   
  
        if (hPipe != INVALID_HANDLE_VALUE)   
            break;   
  
        // Exit if an error other than ERROR_PIPE_BUSY occurs.   
  
        if (GetLastError() != ERROR_PIPE_BUSY)   
        {  
            printf("Could not open pipe");   
            return 0;  
        }  
  
        // All pipe instances are busy, so wait for 20 seconds.   
  
        if (!WaitNamedPipe(lpszPipename, 20000))   
        {   
            printf("Could not open pipe");   
            return 0;  
        }   
    }   
  
    // The pipe connected; change to message-read mode.   
  
    dwMode = PIPE_READMODE_MESSAGE;   
    fSuccess = SetNamedPipeHandleState(   
        hPipe,    // pipe handle   
        &dwMode,  // new pipe mode   
        NULL,     // don\'t set maximum bytes   
        NULL);    // don\'t set maximum time   
    if (!fSuccess)   
    {  
        printf("SetNamedPipeHandleState failed");   
        return 0;  
    }  // 何问起 hovertree.com
  
    // Send a message to the pipe server.   
  
    fSuccess = WriteFile(   
        hPipe,                  // pipe handle   
        lpvMessage,             // message   
        (lstrlen(lpvMessage)+1)*sizeof(TCHAR), // message length   
        &cbWritten,             // bytes written   
        NULL);                  // not overlapped   
    if (!fSuccess)   
    {  
        printf("WriteFile failed");   
        return 0;  
    }  
  
    do   
    {   
        // Read from the pipe.   
  
        fSuccess = ReadFile(   
            hPipe,    // pipe handle   
            chBuf,    // buffer to receive reply   
            BUFSIZE*sizeof(TCHAR),  // size of buffer   
            &cbRead,  // number of bytes read   
            NULL);    // not overlapped   
  
        if (! fSuccess && GetLastError() != ERROR_MORE_DATA)   
            break;   
  
        _tprintf( TEXT("%s\\n"), chBuf );   
    } while (!fSuccess);  // repeat loop if ERROR_MORE_DATA   
  
    getch();  
  
    CloseHandle(hPipe);   
  
    return 0;   
}  

推荐:http://www.cnblogs.com/roucheng/p/vs2015cpp.html

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