boost asio 简单示例

客户端:

1. #include <iostream>
2. #include <boost/asio.hpp>
3. #include <boost/bind.hpp>
4. #include <boost/shared_ptr.hpp>
5. #include <boost/enable_shared_from_this.hpp>
6. using boost::asio::ip::tcp;
7. using boost::asio::ip::address;
8. class session: public boost::enable_shared_from_this<session> {
9. public:
10. (boost::asio::io_service &io_service, tcp::endpoint &endpoint)
11. : io_service_(io_service), socket_(io_service), endpoint_(endpoint)
12. {
13. }
14. void start() {
15. .async_connect(endpoint_,
16. ::bind(&session::handle_connect,
17. (),
18. ::asio::placeholders::error));
19. }
20. private:
21. void handle_connect(const boost::system::error_code &error) {
22. if (error) {
23. if (error.value() != boost::system::errc::operation_canceled) {
24. std::cerr << boost::system::system_error(error).what() << std::endl;
25. }
26. .close();
27. return;
28. }
29. static tcp::no_delay option(true);
30. .set_option(option);
31. strcpy(buf, "Hello World!\n");
32. ::asio::async_write(socket_,
33. ::asio::buffer(buf, strlen(buf)),
34. ::bind(&session::handle_write,
35. (),
36. ::asio::placeholders::error,
37. ::asio::placeholders::bytes_transferred));
38. }
39. void handle_write(const boost::system::error_code& error, size_t bytes_transferred) {
40. memset(buf, sizeof(buf), 0);
41. ::asio::async_read_until(socket_,
42. ,
43. "\n",
44. ::bind(&session::handle_read,
45. (),
46. ::asio::placeholders::error,
47. ::asio::placeholders::bytes_transferred));
48. }
49. void handle_read(const boost::system::error_code& error, size_t bytes_transferred) {
50. std::cout << buf << std::endl;
51. }
52. private:
53. ::asio::io_service &io_service_;
54. ::socket socket_;
55. ::endpoint &endpoint_;
56. char buf[1024];
57. ::asio::streambuf sbuf;
58. };
59. typedef boost::shared_ptr<session> session_ptr;
60. int main(int argc, char* argv[])
61. {
62. ::asio::io_service io_service;
63. ::endpoint endpoint(address::from_string("192.168.1.1"), 10028);
64. (new session(io_service, endpoint));
65. ->start();
66. .run();
67. return 0;
68. }

服务器:

1. #include <string.h>
2. #include <boost/asio.hpp>
3. #include <boost/bind.hpp>
4. #include <boost/shared_ptr.hpp>
5. #include <boost/enable_shared_from_this.hpp>
6. using boost::asio::ip::tcp;
7. using boost::asio::ip::address;
8. class session: public boost::enable_shared_from_this<session> {
9. public:
10. (boost::asio::io_service &io_service): socket_(io_service)
11. {
12. }
13. void start() {
14. static tcp::no_delay option(true);
15. .set_option(option);
16. ::asio::async_read_until(socket_,
17. ,
18. "\n",
19. ::bind(&session::handle_read,
20. (),
21. ::asio::placeholders::error,
22. ::asio::placeholders::bytes_transferred));
23. }
24. ::socket &socket() {
25. return socket_;
26. }
27. private:
28. void handle_write(const boost::system::error_code& error, size_t bytes_transferred) {
29. ::asio::async_read_until(socket_,
30. ,
31. "\n",
32. ::bind(&session::handle_read,
33. (),
34. ::asio::placeholders::error,
35. ::asio::placeholders::bytes_transferred));
36. }
37. void handle_read(const boost::system::error_code& error, size_t bytes_transferred) {
38. ::asio::async_write(socket_,
39. ,
40. ::bind(&session::handle_write,
41. (),
42. ::asio::placeholders::error,
43. ::asio::placeholders::bytes_transferred));
44. }
45. private:
46. ::socket socket_;
47. ::asio::streambuf sbuf_;
48. };
49. typedef boost::shared_ptr<session> session_ptr;
50. class server {
51. public:
52. (boost::asio::io_service &io_service, tcp::endpoint &endpoint)
53. : io_service_(io_service), acceptor_(io_service, endpoint)
54. {
55. (new session(io_service_));
56. .async_accept(new_session->socket(),
57. ::bind(&server::handle_accept,
58. this,
59. ,
60. ::asio::placeholders::error));
61. }
62. void handle_accept(session_ptr new_session, const boost::system::error_code& error) {
63. if (error) {
64. return;
65. }
66. ->start();
67. .reset(new session(io_service_));
68. .async_accept(new_session->socket(),
69. ::bind(&server::handle_accept,
70. this,
71. ,
72. ::asio::placeholders::error));
73. }
74. void run() {
75. .run();
76. }
77. private:
78. ::asio::io_service &io_service_;
79. ::acceptor acceptor_;
80. };
81. int main(int argc, char* argv[])
82. {
83. ::asio::io_service io_service;
84. ::endpoint endpoint(address::from_string("192.168.1.1"), 10028);
85. (io_service, endpoint);
86. .run();
87. return 0;
88. }

编译:

g++ -Wall -o client client.cpp -lboost_system

g++ -Wall -o server server.cpp -lboost_system

这里需要注意的是: async_write, async_read, async_read_until 都是需要达到特定条件才会调用回调函数,

在调用回调函数之前, 不能再次调用, 否则接收到的数据很可能是乱的. 所以, 在实际代码当中, 会有一个写缓冲队列, 当需要write的时, 先放到队列中, 如果队列个数为1, 则调用async_write, 否则等待函数回调, 当函数回调时将首个元素从队列中移除, 然后接着发送下一个, 直到队列为空.