Re: Simplest way to download a web page and print the content to stdout with boost

From:
gervaz <gervaz@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Sun, 13 Jun 2010 06:31:34 -0700 (PDT)
Message-ID:
<9965a5c5-a872-4dcf-b1c8-7057a7d19c87@w31g2000yqb.googlegroups.com>
On Jun 13, 1:42 pm, "Francesco S. Carta" <entul...@gmail.com> wrote:

gervaz <ger...@gmail.com> wrote:

Hi all,
can you provide me the easiest way to download a web page (e.g.http://w=

ww.nytimes.com) and print the output to stdout using the boost

library?

Thanks,
Mattia


Yes, we can :-)

Sorry, but you should try to find the way by yourself first - that's
not hard, split the problem and ask Google, find pointers and follow
them, try to write some code and compile it. If you don't succeed you
can post here your attempts and someone will eventually point out the
mistakes.

--
FSChttp://userscripts.org/scripts/show/59948


Ok, nice advice :P

Here what I've done (adapted from what I've found reading the doc and
googling):

#include <iostream>
#include <boost/asio.hpp>

int main()
{
    boost::asio::io_service io_service ;
    boost::asio::ip::tcp::resolver resolver(io_service) ;
    boost::asio::ip::tcp::resolver::query query("www.nytimes.com",
"http");
    boost::asio::ip::tcp::resolver::iterator iter =
resolver.resolve(query);
    boost::asio::ip::tcp::resolver::iterator end;
    boost::asio::ip::tcp::endpoint endpoint;
    while (iter != end)
    {
        endpoint = *iter++;
        std::cout << endpoint << std::endl;
    }

    boost::asio::ip::tcp::socket socket(io_service);
    socket.connect(endpoint);

    boost::asio::streambuf request;
    std::ostream request_stream(&request);
    request_stream << "GET / HTTP/1.0\r\n";
    request_stream << "Host: localhost \r\n";
    request_stream << "Accept: */*\r\n";
    request_stream << "Connection: close\r\n\r\n";

    boost::asio::write(socket, request);

    boost::asio::streambuf response;
    boost::asio::read_until(socket, response, "\r\n\r\n");

    std::cout << &response << std::endl;

    return 0;
}

But I'm not able to retrieve the entire web content.
Other questions:
- the while loop seems like an iterator loop, but what
boost::asio::ip::tcp::resolver::iterator end stands for? Is a zero
value?
- to see the output I had to use &response, why?

Thanks, but I've come up with the solution in 30 mins and still have
to learn a lot of C++.

Mattia

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