premiere-libtorrent/docs/python_binding.rst

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=========================
libtorrent python binding
=========================
:Author: Arvid Norberg, arvid@libtorrent.org
.. contents:: Table of contents
:depth: 2
:backlinks: none
building
========
Building the libtorrent python bindings will produce a shared library (DLL)
which is a python module that can be imported in a python program.
building using setup.py
-----------------------
There is a ``setup.py`` shipped with libtorrent that can be used on windows.
On windows the setup.py will invoke ``bjam`` and assume that you have boost
sources at ``$BOOST_PATH``. The resulting executable is self-contained, it does
not depend any boost or libtorrent dlls.
On other systems, the setup.py is generated by running
``./configure --enable-python-binding``.
To build the Python bindings do:
1. Run::
python setup.py build
2. As root, run::
python setup.py install
building using boost build
--------------------------
To set up your build environment, you need to add some settings to your
``$BOOST_BUILD_PATH/user-config.jam``.
Make sure your user config contains the following line::
using python : 2.3 ;
Set the version to the version of python you have installed or want to use. If
you've installed python in a non-standard location, you have to add the prefix
path used when you installed python as a second option. Like this::
using python : 2.6 : /usr/bin/python2.6 : /usr/include/python2.6 : /usr/lib/python2.6 ;
The bindings require *at least* python version 2.2.
For more information on how to install and set up boost-build, see the
`building libtorrent`__ section.
.. __: building.html#step-2-setup-bbv2
Once you have boost-build set up, you cd to the ``bindings/python``
directory and invoke ``bjam`` with the apropriate settings. For the available
build variants, see `libtorrent build options`_.
.. _`libtorrent build options`: building.html#step-3-building-libtorrent
For example::
$ bjam dht-support=on link=static
On Mac OS X, this will produce the following python module::
bin/darwin-4.0/release/dht-support-on/link-static/logging-none/threading-multi/libtorrent.so
using libtorrent in python
==========================
The python interface is nearly identical to the C++ interface. Please refer to
the `library reference`_. The main differences are:
asio::tcp::endpoint
The endpoint type is represented as a tuple of a string (as the address) and an int for
the port number. E.g. ``('127.0.0.1', 6881)`` represents the localhost port 6881.
lt::time_duration
The time duration is represented as a number of seconds in a regular integer.
The following functions takes a reference to a container that is filled with
entries by the function. The python equivalent of these functions instead returns
a list of entries.
* torrent_handle::get_peer_info
* torrent_handle::file_progress
* torrent_handle::get_download_queue
* torrent_handle::piece_availability
``create_torrent::add_node()`` takes two arguments, one string and one integer,
instead of a pair. The string is the address and the integer is the port.
``session::apply_settings()`` accepts a dictionary with keys matching the names
of settings in settings_pack.
When calling ``apply_settings``, the dictionary does not need to have every settings set,
keys that are not present are not updated.
To get a python dictionary of the settings, call ``session::get_settings``.
.. _`library reference`: reference.html
Retrieving session statistics in Python is more convenient than that in C++.
The statistics are stored as an array in ``session_stats_alert``, which will be posted after calling ``post_session_stats()`` in the ``session`` object.
In order to interpret the statistics array, in C++ it is required to call ``session_stats_metrics()`` to get the indices of these metrics, while in Python it can be done using ``session_stats_alert.values["NAME_OF_METRIC"]``, where ``NAME_OF_METRIC`` is the name of a metric.
For an example python program, see ``client.py`` in the ``bindings/python``
directory.
A very simple example usage of the module would be something like this::
import libtorrent as lt
import time
ses = lt.session()
ses.listen_on(6881, 6891)
e = lt.bdecode(open("test.torrent", 'rb').read())
info = lt.torrent_info(e)
params = { 'save_path': '.', \
'storage_mode': lt.storage_mode_t.storage_mode_sparse, \
'ti': info }
h = ses.add_torrent(params)
s = h.status()
while (not s.is_seeding):
s = h.status()
state_str = ['queued', 'checking', 'downloading metadata', \
'downloading', 'finished', 'seeding', 'allocating']
print '%.2f%% complete (down: %.1f kb/s up: %.1f kB/s peers: %d) %s' % \
(s.progress * 100, s.download_rate / 1000, s.upload_rate / 1000, \
s.num_peers, state_str[s.state])
time.sleep(1)