我不知道,如果異步版本是必須的,所以我建議你給一個嘗試同步版本,因爲它更容易跟隨執行路徑:
/*
Compile with
g++ -lpthread -lboost_system -lboost_thread -ohttp http.cpp
*/
#include <iostream>
#include <string>
#include <vector>
#include <cstdlib>
#include <boost/asio.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/thread/thread.hpp>
using std::cout;
using std::endl;
using std::vector;
using std::string;
using boost::asio::ip::tcp;
using boost::asio::ip::address;
using boost::asio::io_service;
using boost::asio::buffer;
using boost::system::error_code;
using boost::system::system_error;
int main()
{
try
{
unsigned int PORT = 80;
const string HOST = "216.58.214.238";
const string HTTP_REQUEST = "GET /index.html HTTP/1.0\n\n";
io_service ios;
tcp::endpoint ip_port(address::from_string(HOST), PORT);
while (true)
{
tcp::socket client(ios);
client.connect(ip_port);
const int BUFLEN = 1024;
vector<char> buf(BUFLEN);
client.send(buffer(HTTP_REQUEST, HTTP_REQUEST.size()));
error_code error;
int len = client.receive(buffer(buf, BUFLEN), 0, error);
cout << "main(): buf.data()=";
cout.write(buf.data(), len);
cout << endl;
boost::this_thread::sleep(boost::posix_time::milliseconds(1000));
}
}
catch (system_error& exc)
{
cout << "main(): exc.what()=" << exc.what() << endl;
}
return EXIT_SUCCESS;
}
由於在每次請求(返回狀態302)之後谷歌(它使用IP地址)關閉連接,因此每次在循環內創建套接字。
在其他一些情況下,HTTP連接不必由服務器關閉,因此可以重新使用套接字。