boost 1.59之 boost::asio::ssl (5)

下面是boost官方给出的ssl服务端例子： 

首先，声明了一个流类型的socekt 用来作为socket对象：

  1: typedef boost::asio::ssl::stream<boost::asio::ip::tcp::socket> ssl_socket;

接下来是session类：

  1: class session
  2: {
  3: public:
  4:   session(boost::asio::io_service& io_service,
  5:       boost::asio::ssl::context& context)
  6:     : socket_(io_service, context)
  7:   {
  8:   }
  9: 
 10:   ssl_socket::lowest_layer_type& socket()
 11:   {
 12:     return socket_.lowest_layer();
 13:   }
 14: 
 15:   void start()
 16:   {
 17:     socket_.async_handshake(boost::asio::ssl::stream_base::server,
 18:         boost::bind(&session::handle_handshake, this,
 19:           boost::asio::placeholders::error));
 20:   }
 21: 
 22:   void handle_handshake(const boost::system::error_code& error)
 23:   {
 24:     if (!error)
 25:     {
 26:       socket_.async_read_some(boost::asio::buffer(data_, max_length),
 27:           boost::bind(&session::handle_read, this,
 28:             boost::asio::placeholders::error,
 29:             boost::asio::placeholders::bytes_transferred));
 30:     }
 31:     else
 32:     {
 33:       delete this;
 34:     }
 35:   }
 36: 
 37:   void handle_read(const boost::system::error_code& error,
 38:       size_t bytes_transferred)
 39:   {
 40:     if (!error)
 41:     {
 42:       boost::asio::async_write(socket_,
 43:           boost::asio::buffer(data_, bytes_transferred),
 44:           boost::bind(&session::handle_write, this,
 45:             boost::asio::placeholders::error));
 46:     }
 47:     else
 48:     {
 49:       delete this;
 50:     }
 51:   }
 52: 
 53:   void handle_write(const boost::system::error_code& error)
 54:   {
 55:     if (!error)
 56:     {
 57:       socket_.async_read_some(boost::asio::buffer(data_, max_length),
 58:           boost::bind(&session::handle_read, this,
 59:             boost::asio::placeholders::error,
 60:             boost::asio::placeholders::bytes_transferred));
 61:     }
 62:     else
 63:     {
 64:       delete this;
 65:     }
 66:   }
 67: 
 68: private:
 69:   ssl_socket socket_;
 70:   enum { max_length = 1024 };
 71:   char data_[max_length];
 72: };

session类 ，主要的功能就是通信，做一些数据处理的操作。session类声明了3个私有的变量，一个socket，一个枚举的长度值max_length，一个data_作为缓冲区。

session类，提供了2个成员函数，3个回调函数，2个成员函数，第一个socket()的功能是获取一个底层的ssl_socket,第二个start函数的作用是进行通信。

在start()函数中，使用ssl_socket 进行handshake操作，进行数据交互，其回调函数hand_handshake回调成功，则执行读操作，后续是一样的过程；

session类最重要的还是数据的操作，ssl_socket提供了socket加密，此处可忽略数据的加密。

下面是server类：

  1: class server
  2: {
  3: public:
  4:   server(boost::asio::io_service& io_service, unsigned short port)
  5:     : io_service_(io_service),
  6:       acceptor_(io_service,
  7:           boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port)),
  8:       context_(boost::asio::ssl::context::sslv23)
  9:   {
 10:     context_.set_options(                                                           //设置了context的选项
 11:         boost::asio::ssl::context::default_workarounds
 12:         | boost::asio::ssl::context::no_sslv2
 13:         | boost::asio::ssl::context::single_dh_use);
 14:     context_.set_password_callback(boost::bind(&server::get_password, this));       //设置回调函数,获取密码
 15:     context_.use_certificate_chain_file("server.pem");
 16:     context_.use_private_key_file("server.pem", boost::asio::ssl::context::pem);
 17:     context_.use_tmp_dh_file("dh512.pem");
 18: 
 19:     start_accept();
 20:   }
 21: 
 22:   std::string get_password() const                                                //context的回调函数，用于获取密码
 23:   {
 24:     return "test";
 25:   }
 26: 
 27:   void start_accept()                                                              //start_accept 执行连接客户端操作
 28:   {
 29:     session* new_session = new session(io_service_, context_);
 30:     acceptor_.async_accept(new_session->socket(),
 31:         boost::bind(&server::handle_accept, this, new_session,
 32:           boost::asio::placeholders::error));
 33:   }
 34: 
 35:   void handle_accept(session* new_session,                                          //执行回调函数
 36:       const boost::system::error_code& error)
 37:   {
 38:     if (!error)
 39:     {
 40:       new_session->start();
 41:     }
 42:     else
 43:     {
 44:       delete new_session;
 45:     }
 46: 
 47:     start_accept();
 48:   }
 49: 
 50: private:
 51:   boost::asio::io_service& io_service_;
 52:   boost::asio::ip::tcp::acceptor acceptor_;
 53:   boost::asio::ssl::context context_;
 54: };

 

 

总结：

        总的来说，通过ssl的服务端程序，和没有使用ssl的服务端程序的流程是一样的，都是 获取客户端连接->连接成功->执行session通信。

那么，不一样的地方，就是在server类中，需要根据需求设置context 的选项实现加密；boost官方给的例子很简单，实现了一个小小的加密socket的服务端程序，

剩下的功能就需要我们根据自己的需求实现拓展。

 

 

 

 

 

 

 

东西很简单，如果你有疑问，欢迎评论。。。。有则改之无则加勉！！！