discard
Discard 恐怕算是最简单的长连接 TCP 应用层协议，它只需要关注“三个半事件”中的“消息/数据到达”事件，事件处理函数如下：

1: void DiscardServer::onMessage(const muduo::net::TcpConnectionPtr& conn,

2: muduo::net::Buffer* buf,

3: muduo::Timestamp time)

4: {

5: string msg(buf->retrieveAsString()); // 取回读到的全部数据

6: LOG_INFO << conn->name() << " discards " << msg.size() << " bytes at " << time.toString();

7: }剩下的都是例行公事的代码：定义一个 DiscardServer class，以 TcpServer 为成员。 1: #ifndef MUDUO_EXAMPLES_SIMPLE_DISCARD_DISCARD_H 2: #define MUDUO_EXAMPLES_SIMPLE_DISCARD_DISCARD_H 3: 4: #include 5: 6: // RFC 863 7: class DiscardServer

8: {

9: public:

10: DiscardServer(muduo::net::EventLoop* loop,

11: const muduo::net::InetAddress& listenAddr);

12:

13: void start();

14:

15: private:

16: void onConnection(const muduo::net::TcpConnectionPtr& conn);

17:

18: void onMessage(const muduo::net::TcpConnectionPtr& conn,

19: muduo::net::Buffer* buf,

20: muduo::Timestamp time);

21:

22: muduo::net::EventLoop* loop_;

23: muduo::net::TcpServer server_;

24: };

25:

26: #endif // MUDUO_EXAMPLES_SIMPLE_DISCARD_DISCARD_H注册回调函数

1: DiscardServer::DiscardServer(muduo::net::EventLoop* loop,

2: const muduo::net::InetAddress& listenAddr)

3: : loop_(loop),

4: server_(loop, listenAddr, "DiscardServer")

5: {

6: server_.setConnectionCallback(

7: boost::bind(&DiscardServer::onConnection, this, _1));

8: server_.setMessageCallback(

9: boost::bind(&DiscardServer::onMessage, this, _1, _2, _3));

10: }

11:

12: void DiscardServer::start()

13: {

14: server_.start();

15: }

处理连接与数据事件

1: void DiscardServer::onConnection(const muduo::net::TcpConnectionPtr& conn)

2: {

3: LOG_INFO << "DiscardServer - " << conn->peerAddress().toHostPort() << " -> "

4: << conn->localAddress().toHostPort() << " is "

5: << (conn->connected() "UP" : "DOWN");

6: }

7:

8: void DiscardServer::onMessage(const muduo::net::TcpConnectionPtr& conn,

9: muduo::net::Buffer* buf,

10: muduo::Timestamp time)

11: {

12: string msg(buf->retrieveAsString());

13: LOG_INFO << conn->name() << " discards " << msg.size() << " bytes at " << time.toString();

14: }

在 main() 里用 EventLoop 让整个程序转起来

1: #include "discard.h"

2:

3: #include

4: #include

5:

6: using namespace muduo;

7: using namespace muduo::net;

8:

9: int main()

10: {

11: LOG_INFO << "pid = " << getpid();

12: EventLoop loop;

13: InetAddress listenAddr(2009);

14: DiscardServer server(&loop, listenAddr);

15: server.start();

16: loop.loop();

17: }daytime
Daytime 是短连接协议，在发送完当前时间后，由服务端主动断开连接。它只需要关注“三个半事件”中的“连接已建立”事件，事件处理函数如下：

1: void DaytimeServer::onConnection(const muduo::net::TcpConnectionPtr& conn)

2: {

3: LOG_INFO << "DaytimeServer - " << conn->peerAddress().toHostPort() << " -> "

4: << conn->localAddress().toHostPort() << " is "

5: << (conn->connected() "UP" : "DOWN");

6: if (conn->connected()) 7: { 8: conn->send(Timestamp::now().toFormattedString() + " "); // 发送时间字符串 9: conn->shutdown(); // 主动断开连接 10: } 11: }剩下的都是例行公事的代码，为节省篇幅，此处从略，请阅读 muduo/examples/simple/daytime。

用 netcat 扮演客户端，运行结果如下：

$ nc 127.0.0.1 2013
2011-02-02 03:31:26.622647 # 服务器返回的时间字符串