Boost Asio
boost asio 前摄器模型
boost::shared_ptr< boost::asio::io_service > io_service(
new boost::asio::io_service
);
boost::shared_ptr< boost::asio::io_service::work > work(
new boost::asio::io_service::work( *io_service )
);
boost::shared_ptr< boost::asio::io_service::strand > strand(
new boost::asio::io_service::strand( *io_service )
);
// 绑定超时的回调函数
boost::shared_ptr< boost::asio::deadline_timer > timer(
new boost::asio::deadline_timer( *io_service )
);
timer->expires_from_now( boost::posix_time::seconds( 1 ) );
timer->async_wait(
// 超时时间 属于对基础io读写时间的 包装 ，使用装饰者设计模式进行装饰
strand->wrap( boost::bind( &TimerHandler, _1, timer, strand ) )
);
std::cin.get();
io_service->stop();
worker_threads.join_all();
strand->post
// 有序的socket回调
strand.post( boost::bind( &PrintNum, 1 ) );
strand.post( boost::bind( &PrintNum, 2 ) );
strand.post( boost::bind( &PrintNum, 3 ) );
strand.post( boost::bind( &PrintNum, 4 ) );
strand.post( boost::bind( &PrintNum, 5 ) );
// 无顺序的socket回调
// io_service->post( boost::bind( &PrintNum, 1 ) );
// io_service->post( boost::bind( &PrintNum, 2 ) );
// io_service->post( boost::bind( &PrintNum, 3 ) );
// io_service->post( boost::bind( &PrintNum, 4 ) );
// io_service->post( boost::bind( &PrintNum, 5 ) );
io_context
boost_bind
绑定函数
void F1()
{
std::cout << __FUNCTION__ << std::endl;
}
int f(int a , int b){
std::cout<< a<< b <<std::endl;
}
绑定并且调用函数
class MyClass
{
public:
void F3( int i, float f )
{
std::cout << "i: " << i << std::endl;
std::cout << "f: " << f << std::endl;
}
};
// 绑定并且调用
int test_bind_and_call( )
{
MyClass c;
// 绑定的是类 泛型编程实现
boost::bind( &MyClass::F3, &c, 42, 3.14f )();
return 0;
}
- ps 绑定调用课使用参数模板 用_1 , _2 表示引用参数
//bind(f, _1, 5)(x)等价于f(x, 5)，其中_1是一个占位符，表示用第一个参数来替换;
//bind(f, _2, _1)(x, y)等价于f(y, x);
//bind(g, _1, 9, _1)(x)等价于g(x, 9, x);
//bind(g, _3, _3, _3)(x, y, z)等价于g(z, z, z);
//bind(f, _2,_1)(x, y); //f(y, x)
//bind(g, _1, 9, _1)(x); //g(x, 9, x)
//bind(g, _3, _3, _3)(x, y, z); //g(z, z, z)
//bind(g, _1, _1, _1)(x, y, z); //g(x, x, x)
start boost (对库响应介绍，权威) https://www.boost.org/doc/libs/1_62_0/more/getting_started/windows.html
boost asio toturial（对asio介绍，准确完整） https://www.gamedev.net/blogs/entry/2249317-a-guide-to-getting-started-with-boostasio/
一个支持异步读写的socket 客户端 包括实用的定时器功能和回调功能
//
// async_tcp_client.cpp
// ~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include <boost/asio/deadline_timer.hpp>
#include <boost/asio/io_service.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/read_until.hpp>
#include <boost/asio/streambuf.hpp>
#include <boost/asio/write.hpp>
#include <boost/bind.hpp>
#include <iostream>
using boost::asio::deadline_timer;
using boost::asio::ip::tcp;
//
// This class manages socket timeouts by applying the concept of a deadline.
// Some asynchronous operations are given deadlines by which they must complete.
// Deadlines are enforced by an "actor" that persists for the lifetime of the
// client object:
//
// +----------------+
// | |
// | check_deadline |<---+
// | | |
// +----------------+ | async_wait()
// | |
// +---------+
//
// If the deadline actor determines that the deadline has expired, the socket
// is closed and any outstanding operations are consequently cancelled.
//
// Connection establishment involves trying each endpoint in turn until a
// connection is successful, or the available endpoints are exhausted. If the
// deadline actor closes the socket, the connect actor is woken up and moves to
// the next endpoint.
//
// +---------------+
// | |
// | start_connect |<---+
// | | |
// +---------------+ |
// | |
// async_- | +----------------+
// connect() | | |
// +--->| handle_connect |
// | |
// +----------------+
// :
// Once a connection is :
// made, the connect :
// actor forks in two - :
// :
// an actor for reading : and an actor for
// inbound messages: : sending heartbeats:
// :
// +------------+ : +-------------+
// | |<- - - - -+- - - - ->| |
// | start_read | | start_write |<---+
// | |<---+ | | |
// +------------+ | +-------------+ | async_wait()
// | | | |
// async_- | +-------------+ async_- | +--------------+
// read_- | | | write() | | |
// until() +--->| handle_read | +--->| handle_write |
// | | | |
// +-------------+ +--------------+
//
// The input actor reads messages from the socket, where messages are delimited
// by the newline character. The deadline for a complete message is 30 seconds.
//
// The heartbeat actor sends a heartbeat (a message that consists of a single
// newline character) every 10 seconds. In this example, no deadline is applied
// message sending.
//
class client
{
public:
client(boost::asio::io_service& io_service)
: stopped_(false),
socket_(io_service),
deadline_(io_service),
heartbeat_timer_(io_service)
{
}
// Called by the user of the client class to initiate the connection process.
// The endpoint iterator will have been obtained using a tcp::resolver.
void start(tcp::resolver::iterator endpoint_iter)
{
// Start the connect actor.
start_connect(endpoint_iter);
// Start the deadline actor. You will note that we're not setting any
// particular deadline here. Instead, the connect and input actors will
// update the deadline prior to each asynchronous operation.
deadline_.async_wait(boost::bind(&client::check_deadline, this));
}
// This function terminates all the actors to shut down the connection. It
// may be called by the user of the client class, or by the class itself in
// response to graceful termination or an unrecoverable error.
void stop()
{
stopped_ = true;
socket_.close();
deadline_.cancel();
heartbeat_timer_.cancel();
}
private:
void start_connect(tcp::resolver::iterator endpoint_iter)
{
if (endpoint_iter != tcp::resolver::iterator())
{
std::cout << "Trying " << endpoint_iter->endpoint() << "...\n";
// Set a deadline for the connect operation.
deadline_.expires_from_now(boost::posix_time::seconds(60));
// Start the asynchronous connect operation.
socket_.async_connect(endpoint_iter->endpoint(),
boost::bind(&client::handle_connect,
this, _1, endpoint_iter));
}
else
{
// There are no more endpoints to try. Shut down the client.
stop();
}
}
void handle_connect(const boost::system::error_code& ec,
tcp::resolver::iterator endpoint_iter)
{
if (stopped_)
return;
// The async_connect() function automatically opens the socket at the start
// of the asynchronous operation. If the socket is closed at this time then
// the timeout handler must have run first.
if (!socket_.is_open())
{
std::cout << "Connect timed out\n";
// Try the next available endpoint.
start_connect(++endpoint_iter);
}
// Check if the connect operation failed before the deadline expired.
else if (ec)
{
std::cout << "Connect error: " << ec.message() << "\n";
// We need to close the socket used in the previous connection attempt
// before starting a new one.
socket_.close();
// Try the next available endpoint.
start_connect(++endpoint_iter);
}
// Otherwise we have successfully established a connection.
else
{
std::cout << "Connected to " << endpoint_iter->endpoint() << "\n";
// Start the input actor.
start_read();
// Start the heartbeat actor.
start_write();
}
}
void start_read()
{
// Set a deadline for the read operation.
deadline_.expires_from_now(boost::posix_time::seconds(30));
// Start an asynchronous operation to read a newline-delimited message.
boost::asio::async_read_until(socket_, input_buffer_, '\n',
boost::bind(&client::handle_read, this, _1));
}
void handle_read(const boost::system::error_code& ec)
{
if (stopped_)
return;
if (!ec)
{
// Extract the newline-delimited message from the buffer.
std::string line;
std::istream is(&input_buffer_);
std::getline(is, line);
// Empty messages are heartbeats and so ignored.
if (!line.empty())
{
std::cout << "Received: " << line << "\n";
}
start_read();
}
else
{
std::cout << "Error on receive: " << ec.message() << "\n";
stop();
}
}
void start_write()
{
if (stopped_)
return;
// Start an asynchronous operation to send a heartbeat message.
boost::asio::async_write(socket_, boost::asio::buffer("\n", 1),
boost::bind(&client::handle_write, this, _1));
}
void handle_write(const boost::system::error_code& ec)
{
if (stopped_)
return;
if (!ec)
{
// Wait 10 seconds before sending the next heartbeat.
heartbeat_timer_.expires_from_now(boost::posix_time::seconds(10));
heartbeat_timer_.async_wait(boost::bind(&client::start_write, this));
}
else
{
std::cout << "Error on heartbeat: " << ec.message() << "\n";
stop();
}
}
void check_deadline()
{
if (stopped_)
return;
// Check whether the deadline has passed. We compare the deadline against
// the current time since a new asynchronous operation may have moved the
// deadline before this actor had a chance to run.
if (deadline_.expires_at() <= deadline_timer::traits_type::now())
{
// The deadline has passed. The socket is closed so that any outstanding
// asynchronous operations are cancelled.
socket_.close();
// There is no longer an active deadline. The expiry is set to positive
// infinity so that the actor takes no action until a new deadline is set.
deadline_.expires_at(boost::posix_time::pos_infin);
}
// Put the actor back to sleep.
deadline_.async_wait(boost::bind(&client::check_deadline, this));
}
private:
bool stopped_;
tcp::socket socket_;
boost::asio::streambuf input_buffer_;
deadline_timer deadline_;
deadline_timer heartbeat_timer_;
};
int main(int argc, char* argv[])
{
try
{
if (argc != 3)
{
std::cerr << "Usage: client <host> <port>\n";
return 1;
}
boost::asio::io_service io_service;
tcp::resolver r(io_service);
client c(io_service);
c.start(r.resolve(tcp::resolver::query(argv[1], argv[2])));
io_service.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}