Make boost http client - c++

Question

I am new to boost library so my question is probably not the first one in this forum but I couldn't find a similar case.
Currently I am trying to implement a simple HTTP client which calls REST API.
I inspired my self from the example given on the boost's web site: HTTP client with boost
The example is clear enough for a newbie like me but I would like to make the client to be able to execute multiple requests one by one because the example is a one shot: the client sends a GET request to the server, than it receives the response and after that the io_service.run() returns.
So my question is what I need to use from boost in way to make my client always waiting for new requests to send.
I read something about a io_service::work but I am not sure if it is the right way.
Does anybody have done something similar to the client I am trying to make?
Thanks in advance !
Best regard,
Anton

Answer 1

I do not know if asynchronous version is a must, so I would recommend you to give a try to synchronous version, since it's easier to follow the execution path:
/*
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;
}
The socket is created each time within the loop because Google (it's IP address is used) closes the connection after each request (status 302 is returned).
In some other cases, HTTP connection does not have to be closed by a server, so socket can be reused.