restructuring start

Author: kgibbons

C++/src/asio_server.h

@@ -0,0 +1,74 @@
+/*
+This seemed a sufficiently common pattern so as to be worth abstracting.
+
+*/
+
+#ifndef ASIO_SERVER_H
+#define ASIO_SERVER_H
+
+#include <functional>
+#include <memory>
+#include <boost/asio.hpp>
+
+
+// Convenience class for handlers.
+// To use, define a class Foo which inherits from asio_handler<Foo>, calls its
+// constructor, and overwrites 'handle'.
+// eg:
+/*
+class handler: public asio_handler<handler> {
+ public:
+ 	handler(boost::asio::io_service& io_service) : asio_handler(io_service) {}
+	void handle() {
+		// do something like read from socket_
+	}
+}
+
+*/ 
+template<typename T>
+class asio_handler : public std::enable_shared_from_this<T> {
+ public:
+	asio_handler(boost::asio::io_service& io_service)
+    : socket_(io_service) {}
+        
+    boost::asio::local::stream_protocol::socket& socket() {
+    	return socket_;
+    }
+
+	void handle() {
+	
+	}
+	
+ protected:
+	boost::asio::local::stream_protocol::socket socket_;	
+};
+
+
+// HANDLER must have a constructor with a 'boost::asio::io_service&' as its sole parameter,
+// must implement a 'handle' fn taking no parameters.
+// and must implement a 'socket' fn taking no parameters and returning a 'boost::asio::local::stream_protocol::socket'
+// this being the socket it wants to talk on.
+// In practice, just derive from asio_handler.
+template<typename HANDLER>
+class asio_server {
+public:
+	boost::asio::io_service& io_service_;
+	boost::asio::local::stream_protocol::acceptor acceptor_;
+	
+	asio_server(boost::asio::io_service& io_service, boost::asio::local::stream_protocol::endpoint endpoint)
+	: io_service_(io_service), acceptor_(io_service, endpoint) {
+		auto the_session = std::make_shared<HANDLER>(io_service_);
+		acceptor_.async_accept(the_session->socket(), std::bind(&asio_server::handle_accept, this, the_session, std::placeholders::_1));
+	}
+	
+	void handle_accept(std::shared_ptr<HANDLER> session, const boost::system::error_code& error) {
+		if(!error)
+			session->handle();
+		
+		session.reset(new HANDLER(io_service_));
+		acceptor_.async_accept(session->socket(), std::bind(&asio_server::handle_accept, this, session, std::placeholders::_1));
+	}
+};
+
+
+#endif