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我正在尝试使用 winsock/OpenSSL 制作简单的 IMAP 客户端，如果没有其他库，这可能吗？如果是这样，如何发送请求并获得响应？服务器只响应一次，即使没有请求，之后我发送请求和应用程序卡在 SSL_read(..) 函数，而不是超时和 BYE。如何发出正确的请求？ 在此处输入图像描述

bool RequestQueue(const char* serverName)
{
    SOCKET      hSocket = INVALID_SOCKET;
    char        receiveBuf[512];
    ZeroMemory(receiveBuf,512); 
    char        requestBuf[512];
    ZeroMemory(requestBuf,512); 
    sockaddr_in sockAddr = {0};
    bool        bSuccess = true;

    //SSL
    SSL* ssl;
    SSL_CTX* ctx;

    try
    {       
        //Look up hostname and fill sockaddr_in structure
        cout<< "Looking up hostname "<<serverName<<"...";
        FillSockAddr(&sockAddr,serverName,IMAP_SERVER_PORT);
        cout<< "found.\n";

        //creating socket
        cout<<"Creating socket..";
        if((hSocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP)) == INVALID_SOCKET)
            throw exception("could not create socket!");
        cout<<"created.\n";

            //Connect to server
        cout<<"Attempting to connect to "<< inet_ntoa(sockAddr.sin_addr)
            <<":"<<IMAP_SERVER_PORT<<" ...";
        if(connect(hSocket,(sockaddr*)(&sockAddr),sizeof(sockAddr))!= 0)
            throw exception("could not connect!");

        cout<<"connected\n";

        ctx = SSL_CTX_new(SSLv23_client_method());
        if(!ctx)
            throw exception("SSL_CTX_new error");

        ssl = SSL_new(ctx);
        SSL_CTX_free(ctx);
        if(!ssl)
            throw exception("ssl initializing error");

        SSL_set_fd(ssl,hSocket);
        if(SSL_connect(ssl) != 1)
            throw exception("SSL_connect error");

        int reqLen;
        int retLen;
        cout<<"==============\n";
        cout<<"====begin=====\n";
        cout<<"==============\n";

        retLen = SSL_read(ssl,receiveBuf,sizeof(receiveBuf));
        if(retLen<0)
            throw exception("SSL_read error.");
        cout<<"S: "<<receiveBuf;

        strcpy(requestBuf,"a001 CAPABILITY");
        reqLen = strlen(requestBuf);
        SSL_write(ssl,requestBuf,reqLen);
        cout<<"C: "<<requestBuf<<endl;  

        ZeroMemory(receiveBuf,sizeof(receiveBuf));
        retLen = SSL_read(ssl,receiveBuf,sizeof(receiveBuf));
        if(retLen<0)
            throw exception("SSL_read error.");

        cout<<"S: "<<receiveBuf;                    
    }
    catch(exception e)
    {
        cout<<"Error : "<<e.what()<<endl;
    }
    if(hSocket != INVALID_SOCKET)
    {
        SSL_shutdown(ssl);
        closesocket(hSocket);
        SSL_free(ssl);      
    }

    return bSuccess;
}
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1 回答 1

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我没有深入分析您的代码，但我可以看到一个明显的问题。根据RFC 3501：

客户端和服务器传输的所有交互都是行的形式，即以 CRLF 结尾的字符串。IMAP4rev1 客户端或服务器的协议接收器正在读取一行，或者正在读取具有已知计数的八位字节序列，后跟一行。

在您的代码中，您没有使用 CRLF 终止命令。尝试更换

strcpy(requestBuf,"a001 CAPABILITY");

和

strcpy(requestBuf,"a001 CAPABILITY\r\n");

此外，您最好先不使用 SSL，然后再添加它——这将大大简化调试（即使用Wireshark）。

于 2012-12-08T11:12:45.903 回答