premiere-libtorrent/docs/examples.rst

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===================
libtorrent Examples
===================
:Author: Arvid Norberg, arvid@rasterbar.com
.. contents:: Table of contents
:depth: 2
:backlinks: none
examples
========
Except for the example programs in this manual, there's also a bigger example
of a (little bit) more complete client, ``client_test``. There are separate
instructions for how to use it here__ if you'd like to try it. Note that building
``client_test`` also requires boost.regex and boost.program_options library.
__ client_test.html
dump_torrent
------------
This is an example of a program that will take a torrent-file as a parameter and
print information about it to std out::
#include <iostream>
#include <fstream>
#include <iterator>
#include <iomanip>
#include "libtorrent/entry.hpp"
#include "libtorrent/bencode.hpp"
#include "libtorrent/torrent_info.hpp"
int main(int argc, char* argv[])
{
using namespace libtorrent;
if (argc != 2)
{
std::cerr << "usage: dump_torrent torrent-file\n";
return 1;
}
try
{
std::ifstream in(argv[1], std::ios_base::binary);
in.unsetf(std::ios_base::skipws);
entry e = bdecode(std::istream_iterator<char>(in)
, std::istream_iterator<char>());
std::cout << "\n\n----- raw info -----\n\n";
e.print(std::cout);
torrent_info t(e);
// print info about torrent
std::cout << "\n\n----- torrent file info -----\n\n";
std::cout << "nodes:\n";
typedef std::vector<std::pair<std::string, int> > node_vec;
node_vec const& nodes = t.nodes();
for (node_vec::const_iterator i = nodes.begin(), end(nodes.end());
i != end; ++i)
{
std::cout << i->first << ":" << i->second << "\n";
}
std::cout << "trackers:\n";
for (std::vector<announce_entry>::const_iterator i
= t.trackers().begin(); i != t.trackers().end(); ++i)
{
std::cout << i->tier << ": " << i->url << "\n";
}
std::cout << "number of pieces: " << t.num_pieces() << "\n";
std::cout << "piece length: " << t.piece_length() << "\n";
std::cout << "info hash: " << t.info_hash() << "\n";
std::cout << "comment: " << t.comment() << "\n";
std::cout << "created by: " << t.creator() << "\n";
std::cout << "files:\n";
for (torrent_info::file_iterator i = t.begin_files();
i != t.end_files(); ++i)
{
std::cout << " " << std::setw(11) << i->size
<< " " << i->path.string() << "\n";
}
}
catch (std::exception& e)
{
std::cout << e.what() << "\n";
}
return 0;
}
simple client
-------------
This is a simple client. It doesn't have much output to keep it simple::
#include <iostream>
#include <fstream>
#include <iterator>
#include <exception>
#include <boost/format.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
#include "libtorrent/entry.hpp"
#include "libtorrent/bencode.hpp"
#include "libtorrent/session.hpp"
int main(int argc, char* argv[])
{
using namespace libtorrent;
if (argc != 2)
{
std::cerr << "usage: ./simple_cient torrent-file\n"
"to stop the client, press return.\n";
return 1;
}
try
{
session s;
s.listen_on(std::make_pair(6881, 6889));
std::ifstream in(argv[1], std::ios_base::binary);
in.unsetf(std::ios_base::skipws);
entry e = bdecode(std::istream_iterator<char>(in)
, std::istream_iterator<char>());
s.add_torrent(torrent_info(e), "");
// wait for the user to end
char a;
std::cin.unsetf(std::ios_base::skipws);
std::cin >> a;
}
catch (std::exception& e)
{
std::cout << e.what() << "\n";
}
return 0;
}
make_torrent
------------
Shows how to create a torrent from a directory tree::
#include <iostream>
#include <fstream>
#include <iterator>
#include <iomanip>
#include "libtorrent/entry.hpp"
#include "libtorrent/bencode.hpp"
#include "libtorrent/torrent_info.hpp"
#include "libtorrent/file.hpp"
#include "libtorrent/storage.hpp"
#include "libtorrent/hasher.hpp"
#include "libtorrent/file_pool.hpp"
#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/filesystem/fstream.hpp>
using namespace boost::filesystem;
using namespace libtorrent;
void add_files(
torrent_info& t
, path const& p
, path const& l)
{
path f(p / l);
if (is_directory(f))
{
for (directory_iterator i(f), end; i != end; ++i)
add_files(t, p, l / i->leaf());
}
else
{
std::cerr << "adding \"" << l.string() << "\"\n";
t.add_file(l, file_size(f));
}
}
int main(int argc, char* argv[])
{
using namespace libtorrent;
using namespace boost::filesystem;
path::default_name_check(no_check);
if (argc != 4)
{
std::cerr << "usage: make_torrent <output torrent-file> "
"<announce url> <file or directory to create torrent from>\n";
return 1;
}
try
{
torrent_info t;
path full_path = complete(path(argv[3]));
ofstream out(complete(path(argv[1])), std::ios_base::binary);
int piece_size = 256 * 1024;
char const* creator_str = "libtorrent";
add_files(t, full_path.branch_path(), full_path.leaf());
t.set_piece_size(piece_size);
file_pool fp;
storage st(t, full_path.branch_path(), fp);
t.add_tracker(argv[2]);
// calculate the hash for all pieces
int num = t.num_pieces();
std::vector<char> buf(piece_size);
for (int i = 0; i < num; ++i)
{
st.read(&buf[0], i, 0, t.piece_size(i));
hasher h(&buf[0], t.piece_size(i));
t.set_hash(i, h.final());
std::cerr << (i+1) << "/" << num << "\r";
}
t.set_creator(creator_str);
// create the torrent and print it to out
entry e = t.create_torrent();
libtorrent::bencode(std::ostream_iterator<char>(out), e);
}
catch (std::exception& e)
{
std::cerr << e.what() << "\n";
}
return 0;
}