菜鸟笔记因为UDP不能保证所有消息都抵达接收者，所以不能保证消息都以回车结尾。
在服务端，收到消息后，简单的回发给客户端，并且不关闭socket，因为这是UDP。
一.UDP同步客户端
UDP客户端比TCP客户端要简单：
#ifdef WIN32
#define _WIN32_WINNT 0x0501
#include <stdio.h>
#endif
#include <boost/thread.hpp>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
using namespace boost::asio;
io_service service;
ip::udp::endpoint ep(ip::address::from_string("127.0.0.1"), 8001);
void sync_echo(std::string msg) {
ip::udp::socket sock(service, ip::udp::endpoint(ip::udp::v4(), 0));
sock.send_to(buffer(msg), ep);
char buff[1024];
ip::udp::endpoint sender_ep;
int bytes = sock.receive_from(buffer(buff), sender_ep);
std::string copy(buff, bytes);
std::cout << "server echoed our " << msg << ": "
<< (copy == msg ? "OK" : "FAIL") << std::endl;
sock.close();
}
int main(int argc, char* argv[]) {
char* messages[] = { "Can", "ge", "ge" , "blog" , 0 };
boost::thread_group threads;
for (char ** message = messages; *message; ++message) {
threads.create_thread(boost::bind(sync_echo, *message));
boost::this_thread::sleep(boost::posix_time::millisec(100));
}
threads.join_all();
system("pause");
}
二.UDP同步服务端
UDP服务端会是你写过的最简单的服务端：
#ifdef WIN32
#define _WIN32_WINNT 0x0501
#include <stdio.h>
#endif
#include <boost/bind.hpp>
#include <boost/asio.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
using namespace boost::asio;
using namespace boost::posix_time;
io_service service;
void handle_connections() {
char buff[1024];
ip::udp::socket sock(service, ip::udp::endpoint(ip::udp::v4(), 8001));
while (true) {
ip::udp::endpoint sender_ep;
int bytes = sock.receive_from(buffer(buff), sender_ep);
std::string msg(buff, bytes);
sock.send_to(buffer(msg), sender_ep);
}
}
int main(int argc, char* argv[]) {
handle_connections();
}</code></pre> 下面是客户端回显的结果，当然要先启动服务端。
<p style="text-align:justify"><img src="https://static.coonote.com/2021/12/7106881665834187682.png" class="aligncenter"><br></p>
<p><strong>三.UDP异步客户端</strong></p>
<pre><code>#ifdef WIN32
#define _WIN32_WINNT 0x0501
#include <stdio.h>
#endif
#include <boost/thread.hpp>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
using namespace boost::asio;
io_service service;
ip::udp::endpoint ep(ip::address::from_string("127.0.0.1"), 8001);
#define MEM_FN(x) boost::bind(&self_type::x, shared_from_this())
#define MEM_FN1(x,y) boost::bind(&self_type::x, shared_from_this(),y)
#define MEM_FN2(x,y,z) boost::bind(&self_type::x, shared_from_this(),y,z)
class talk_to_svr : public boost::enable_shared_from_this<talk_to_svr>
, boost::noncopyable {
typedef talk_to_svr self_type;
talk_to_svr(const std::string & message)
: sock_(service, ip::udp::endpoint(ip::udp::v4(), 0)), started_(true), message_(message) {}
void start() {
do_write(message_);
}
public:
typedef boost::system::error_code error_code;
typedef boost::shared_ptr<talk_to_svr> ptr;
static ptr start(const std::string & message) {
ptr new_(new talk_to_svr(message));
new_->start();
return new_;
}
bool started() { return started_; }
private:
void on_read(const error_code & err, size_t bytes) {
if (!err) {
std::string copy(read_buffer_, bytes);
std::cout << "server echoed our " << message_ << ": "
<< (copy == message_ ? "OK" : "FAIL") << std::endl;
}
}
void on_write(const error_code & err, size_t bytes) {
do_read();
}
void do_read() {
sock_.async_receive_from(buffer(read_buffer_), sender_ep,
MEM_FN2(on_read, _1, _2));
}
void do_write(const std::string & msg) {
std::copy(msg.begin(), msg.end(), write_buffer_);
sock_.async_send_to(buffer(write_buffer_, msg.size()), ep,
MEM_FN2(on_write, _1, _2));
}
private:
ip::udp::socket sock_;
ip::udp::endpoint sender_ep;
enum { max_msg = 1024 };
char read_buffer_[max_msg];
char write_buffer_[max_msg];
bool started_;
std::string message_;
};
int main(int argc, char* argv[]) {
char* messages[] = { "Can", "ge", "ge", "blog", 0 };
for (char ** message = messages; *message; ++message) {
talk_to_svr::start(*message);
boost::this_thread::sleep(boost::posix_time::millisec(100));
}
service.run();
system("pause");
}
四.UDP异步服务器
#ifdef WIN32
#define _WIN32_WINNT 0x0501
#include <stdio.h>
#endif
#include <boost/bind.hpp>
#include <boost/asio.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
using namespace boost::asio;
using namespace boost::posix_time;
io_service service;
#define MEM_FN(x) boost::bind(&self_type::x, shared_from_this())
#define MEM_FN1(x,y) boost::bind(&self_type::x, shared_from_this(),y)
#define MEM_FN2(x,y,z) boost::bind(&self_type::x, shared_from_this(),y,z)
class talk_to_client : public boost::enable_shared_from_this<talk_to_client>, boost::noncopyable {
typedef talk_to_client self_type;
talk_to_client() : sock_(service, ip::udp::endpoint(ip::udp::v4(), 8001)), started_(false) {}
public:
typedef boost::system::error_code error_code;
typedef boost::shared_ptr<talk_to_client> ptr;
void start() {
started_ = true;
do_read();
}
static ptr new_() {
ptr new_(new talk_to_client);
return new_;
}
ip::udp::socket & sock() { return sock_; }
private:
void on_read(const error_code & err, size_t bytes) {
if (!err) {
std::string msg(read_buffer_, bytes);
do_write(msg);
}
}
void on_write(const error_code & err, size_t bytes) {
do_read();
}
void do_read() {
sock_.async_receive_from(buffer(read_buffer_), sender_ep,
MEM_FN2(on_read, _1, _2));
}
void do_write(const std::string & msg) {
std::copy(msg.begin(), msg.end(), write_buffer_);
sock_.async_send_to(buffer(write_buffer_, msg.size()), sender_ep,
MEM_FN2(on_write, _1, _2));
}
private:
ip::udp::socket sock_;
ip::udp::endpoint sender_ep;
enum { max_msg = 1024 };
char read_buffer_[max_msg];
char write_buffer_[max_msg];
bool started_;
};
int main(int argc, char* argv[]) {
talk_to_client::ptr client = talk_to_client::new_();
client->start();
service.run();
}
客户端回显结果和同步时一样，如下：
