"Hello world" HTTP client

..todo::

Since we have a "Hello World" HTTP server, let's then create an HTTP client to

access that server. This client will be similar to the HTTP client we made

earlier in the documentation.

Take the HTTP client example and server example and describe

what's happening.

The Code

We want to create a simple HTTP client that just makes a request to the HTTP

server that we created earlier. This really simple client will look like this:

..code-block::c++

#include <boost/network/protocol/http/client.hpp>

#include <string>

#include <sstream>

#include <iostream>

namespace http = boost::network::http;

int main(int argc, char * argv[]) {

if (argc != 3) {

std::cerr << "Usage: " << argv[0] << " address port" << std::endl;

return 1;

}

try {

http::client client;

std::ostringstream url;

url << "http://" << argv[1] << ":" << argv[2] << "/";

http::client::request request(url.str());

http::client::response response =

client.get(request);

std::cout << body(response) << std::endl;

} catch (std::exception & e) {

std::cerr << e.what() << std::endl;

return 1;

}

return 0;

}

Building the Client

Just like with the HTTP Server and HTTP client example before, we can build this

example by doing the following on the shell:

..code-block::bash

This example can be run from the command line as follows:

::

..note::This assumes that you have the ``hello_world_server`` running on

localhost port 8000.

Diving into the Code

All this example shows is how easy it is to write an HTTP client that connects

to an HTTP server, and gets the body of the response. The relevant lines are:

..code-block::c++

http::client client;

http::client::request request(url.str());

http::client::response response =

client.get(request);

std::cout << body(response) << std::endl;

You can then imagine using this in an XML-RPC client, where you can craft the

XML-RPC request as payload which you can pass as the body to a request, then

perform the request via HTTP:

..code-block::c++

http::client client;

http::client::request request("http://my.webservice.com/");

http::client::response =

client.post(request, "application/xml", some_xml_string);

std::data = body(response);