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我正在尝试制作一个与现有聊天客户端通信的 TCP 聊天服务器。我无权访问现有聊天客户端的代码，但我知道它通过网络发送的内容以及我应该发回的内容。

我正在尝试使用该boost::asio库，但由于某种原因它不想执行第二个boost::asio::async_read，而且我一生都无法弄清楚。

我编辑了boost::asio::async_read函数来添加一个printf( "async_read\n" );只是为了看看它是否真的被调用了，确实是这样。

这是我得到的输出：

[INFO] Adding Server 0.0.0.0:10013
[INFO] Starting Servers

[ROOM] Client Joined (#1)
async_read
[HEADER] \x70
[HEADER] 112
async_read
[ROOM] Client Left (#1)

客户端一个接一个地发送两个数据包：

Packet 1 (Header : Body Size):
00000000  70 00                                            p.

Packet 2 (Body : Auth Info):
00000002  00 0c 59 38 3d 00 38 34  62 63 34 35 62 65 35 66 ..Y8=.84 bc45be5f
00000012  36 33 34 34 35 66 63 33  38 32 34 32 31 61 39 39 63445fc3 82421a99
00000022  31 66 37 66 39 62 00 31  30 35 2e 32 33 36 2e 33 1f7f9b.1 05.236.3
00000032  35 2e 39 39 00 61 39 33  35 66 65 62 32 64 62 66 5.99.a93 5feb2dbf
00000042  36 65 38 66 32 39 30 62  32 61 36 64 36 37 61 35 6e8f290b 2a6d67a5
00000052  31 36 63 65 65 30 36 34  64 38 64 63 37 00 28 00 16cee064 d8dc7.(.
00000062  00 00 81 06 01 00 77 61  63 00 03 00 09 00 00 00 ......wa c.......

如您所见，服务器代码仅接收第一个数据包，然后在第二个boost::asio::async_read调用时停止

这是修改后的代码：

typedef std::deque< ChatMessage > ChatMessageQueue;

class ChatParticipant
{
public:
    virtual ~ChatParticipant( ) { }
    virtual void Deliver( const ChatMessage &Message ) = 0;
};

typedef boost::shared_ptr< ChatParticipant > ChatParticipantPtr;

class ChatRoom
{
public:
    void join( ChatParticipantPtr Participant )
    {
        m_Participants.insert( Participant );
        printf( "[ROOM] Client Joined (#%i)\n", m_Participants.size( ) );
        std::for_each( m_RecentMessages.begin( ), m_RecentMessages.end( ),
            boost::bind( &ChatParticipant::Deliver, Participant, _1 ) );
    }

    void leave( ChatParticipantPtr Participant )
    {
        printf( "[ROOM] Client Left (#%i)\n", m_Participants.count( Participant ) );
        m_Participants.erase( Participant );
    }

    void deliver( const ChatMessage &Message )
    {
        m_RecentMessages.push_back( Message );
        while( m_RecentMessages.size( ) > MaxRecentMessages )
            m_RecentMessages.pop_front( );

        std::for_each( m_Participants.begin( ), m_Participants.end( ),
            boost::bind( &ChatParticipant::Deliver, _1, boost::ref( Message ) ) );
    }

private:
    std::set< ChatParticipantPtr > m_Participants;
    enum { MaxRecentMessages = 100 };
    ChatMessageQueue m_RecentMessages;
};

class ChatSession : public ChatParticipant, public boost::enable_shared_from_this< ChatSession >
{
public:
    ChatSession( boost::asio::io_service &IOService, ChatRoom &Room ) : m_Socket( IOService ), m_Room( Room )
    {
    }

    tcp::socket &Socket( )
    {
        return m_Socket;
    }

    void Start( )
    {
        m_Room.join( shared_from_this( ) );
        boost::asio::async_read( m_Socket, 
            boost::asio::buffer( m_ReadMessage.data( ), ChatMessage::HeaderLength ),
            boost::bind( &ChatSession::Handle_ReadHeader, shared_from_this( ), boost::asio::placeholders::error ) );
    }

    void Deliver( const ChatMessage &Message )
    {
        bool write_in_progress = !m_WriteMessages.empty( );
        m_WriteMessages.push_back( Message );
        if( !write_in_progress )
        {
            boost::asio::async_write( m_Socket,
                boost::asio::buffer( m_WriteMessages.front( ).data( ), m_WriteMessages.front( ).length( ) ),
                boost::bind( &ChatSession::Handle_Write, shared_from_this( ), boost::asio::placeholders::error ) );
        }
    }

    void Handle_ReadHeader( const boost::system::error_code &Error )
    {
        if( Error )
        {
            m_Room.leave( shared_from_this( ) );
            return;
        }

        if( m_ReadMessage.DecodeHeader( ) )
        {
            printf( "[HEADER] %s\n", Strings::StringToHex( m_ReadMessage.data( ) ).c_str( ) );
            printf( "[HEADER] %i\n", m_ReadMessage.length( ) );
            boost::asio::async_read( m_Socket,
                boost::asio::buffer( m_ReadMessage.body( ), m_ReadMessage.length( ) ),
                boost::bind( &ChatSession::Handle_ReadBody, shared_from_this( ), boost::asio::placeholders::error ) );
        }
    }

    void Handle_ReadBody( const boost::system::error_code &Error )
    {
        if( Error )
        {
            m_Room.leave( shared_from_this( ) );
            return;
        }

        printf( "[BODY] %s\n", Strings::StringToHex( m_ReadMessage.body( ) ).c_str( ) );
        //m_Room.deliver( m_ReadMessage );
        boost::asio::async_read( m_Socket,
            boost::asio::buffer( m_ReadMessage.data( ), ChatMessage::HeaderLength ),
            boost::bind( &ChatSession::Handle_ReadHeader, shared_from_this( ), boost::asio::placeholders::error ) );
    }

    void Handle_Write( const boost::system::error_code &Error )
    {
        if( Error )
        {
            m_Room.leave( shared_from_this( ) );
            return;
        }

        m_WriteMessages.pop_front( );
        if( !m_WriteMessages.empty( ) )
        {
            boost::asio::async_write( m_Socket,
                boost::asio::buffer( m_WriteMessages.front( ).data( ), m_WriteMessages.front( ).length( ) ),
                boost::bind( &ChatSession::Handle_Write, shared_from_this( ), boost::asio::placeholders::error ) );
        }
    }

private:
    tcp::socket m_Socket;
    ChatRoom &m_Room;
    ChatMessage m_ReadMessage;
    ChatMessageQueue m_WriteMessages;
};

typedef boost::shared_ptr< ChatSession > ChatSessionPtr;

class ChatServer
{
public:
    ChatServer( boost::asio::io_service &IOService, const tcp::endpoint &EndPoint ) : m_IOService( IOService ), m_Acceptor( IOService, EndPoint )
    {
        StartAccepting( );
    }

    void StartAccepting()
    {
        ChatSessionPtr NewSession( new ChatSession( m_IOService, m_Room ) );
        m_Acceptor.async_accept( NewSession->Socket( ),
            boost::bind( &ChatServer::Handle_Accept, this, NewSession, boost::asio::placeholders::error ) );
    }

    void Handle_Accept( ChatSessionPtr Session, const boost::system::error_code& Error )
    {
        if( !Error )
            Session->Start( );

        StartAccepting( );
    }

private:
    boost::asio::io_service &m_IOService;
    tcp::acceptor m_Acceptor;
    ChatRoom m_Room;
};

typedef boost::shared_ptr< ChatServer > ChatServerPtr;

int main( int argc, char **argv, char **envp )
{
    boost::asio::io_service IOService;

    tcp::endpoint EndPoint( tcp::v4( ), 10013 );
    ChatServerPtr Server( new ChatServer( IOService, EndPoint ) );
    printf( "[INFO] Adding Server %s:%i\n", EndPoint.address( ).to_string( ).c_str( ), EndPoint.port( ) );

    IOService.run( );

    return TRUE;
}

你能看出我做错了什么吗？

4

1 回答 1

0

TCP 是面向字节的流，在 API 中没有“数据包”的概念。您的第一次读取是读取 112 个字节（根据您的调试输出），因此您在一次调用中读取标题和正文。

您应该做的是首先通过使用两个字节缓冲区调用 async_read 来读取两个字节长度。当它返回时，您应该对其进行解码并使用该长度来指定要为正文读取的字节数。这应该是您在缓冲区参数中传递给您下一次调用 async_read 的字节数。

于 2013-04-26T07:32:33.360 回答