+.. SPDX-FileCopyrightText: 2018-2023 kaliko <kaliko@azylum.org>
+.. SPDX-License-Identifier: LGPL-3.0-or-later
+
Using the client library
=========================
# test ${XDG_RUNTIME_DIR}/mpd/socket for existence
# fallback to localhost:6600
# connect support host/port argument as well
- print(client.mpd_version) # print the mpd protocol version
- print(client.cmd('foo', 42)) # print result of the request "cmd foo 42"
- # (nb. for actual command, see link to the protocol below)
+ print(client.mpd_version) # print the MPD protocol version
+ client.setvol('42') # sets the volume
client.disconnect() # disconnect from the server
-In the example above `cmd` in not an actual MPD command, for a list of
-supported commands, their arguments (as MPD currently understands
-them), and the functions used to parse their responses see :ref:`commands`.
+The MPD command protocol exchanges line-based text records. The client emits a
+command with optional arguments. In the example above the client sends a
+`setvol` command with the string argument `42`.
+
+MPD commands are exposed as :py:class:`musicpd.MPDClient` methods. Methods
+**arguments are python strings**. Some commands are composed of more than one word
+(ie "**tagtypes [disable|enable|all]**"), for these use a `snake case`_ style to
+access the method. Then **"tagtypes enable"** command is called with
+**"tagtypes_enable"**.
+
+Remember MPD protocol is text based, then all MPD command arguments are UTF-8
+strings. In the example above, an integer can be used as argument for the
+`setvol` command, but it is then evaluated as a string when the command is
+written to the socket. To avoid confusion use regular string instead of relying
+on object string representation.
+
+:py:class:`musicpd.MPDClient` methods returns different kinds of objects
+depending on the command. Could be :py:obj:`None`, a single object as a
+:py:obj:`str` or a :py:obj:`dict`, a list of :py:obj:`dict`.
+
+Then :py:class:`musicpd.MPDClient` **methods signatures** are not hard coded
+within this module since the protocol is handled on the server side. Please
+refer to the protocol and MPD commands in `MPD protocol documentation`_ to
+learn how to call commands and what kind of arguments they expect.
+
+Some examples are provided for the most common cases, see :ref:`examples`.
-See the `MPD protocol documentation`_ for more details.
+For a list of currently supported commands in this python module see
+:ref:`commands`.
.. _environment_variables:
Environment variables
---------------------
-The client honors the following environment variables:
+:py:class:`musicpd.MPDClient` honors the following environment variables:
+
+.. envvar:: MPD_HOST
+
+ MPD host (:abbr:`FQDN (fully qualified domain name)`, IP, socket path or abstract socket) and password.
+
+ | To define a **password** set :envvar:`MPD_HOST` to "*password@host*" (password only "*password@*")
+ | For **abstract socket** use "@" as prefix : "*@socket*" and then with a password "*pass@@socket*"
+ | Regular **unix socket** are set with an absolute path: "*/run/mpd/socket*"
+
+.. envvar:: MPD_PORT
+
+ MPD port, relevant for TCP socket only
- * ``MPD_HOST`` MPD host (:abbr:`FQDN (fully qualified domain name)`, socket path or abstract socket) and password.
+.. envvar:: MPD_TIMEOUT
- | To define a password set MPD_HOST to "`password@host`" (password only "`password@`")
- | For abstract socket use "@" as prefix : "`@socket`" and then with a password "`pass@@socket`"
- | Regular unix socket are set with an absolute path: "`/run/mpd/socket`"
- * ``MPD_PORT`` MPD port, relevant for TCP socket only, ie with :abbr:`FQDN (fully qualified domain name)` defined host
- * ``MPD_TIMEOUT`` timeout for connecting to MPD and waiting for MPD’s response in seconds
- * ``XDG_RUNTIME_DIR`` path to look for potential socket: ``${XDG_RUNTIME_DIR}/mpd/socket``
+ socket timeout when connecting to MPD and waiting for MPD’s response (in seconds)
+
+.. envvar:: XDG_RUNTIME_DIR
+
+ path to look for potential socket
.. _default_settings:
Default settings
----------------
- * If ``MPD_HOST`` is not set, then look for a socket in ``${XDG_RUNTIME_DIR}/mpd/socket``
- * If there is no socket use ``localhost``
- * If ``MPD_PORT`` is not set, then use ``6600``
- * If ``MPD_TIMEOUT`` is not set, then uses :py:obj:`musicpd.CONNECTION_TIMEOUT`
+Default host:
+ * use :envvar:`MPD_HOST` environment variable if set, extract password if present,
+ * else use :envvar:`XDG_RUNTIME_DIR` to looks for an existing file in ``${XDG_RUNTIME_DIR}/mpd/socket``, :envvar:`XDG_RUNTIME_DIR` defaults to ``/run`` if not set.
+ * else set host to ``localhost``
+
+Default port:
+ * use :envvar:`MPD_PORT` environment variable if set
+ * else use ``6600``
+Default timeout:
+ * use :envvar:`MPD_TIMEOUT` if set
+ * else use :py:obj:`musicpd.CONNECTION_TIMEOUT`
Context manager
---------------
Ranges
------
-Provide a 2-tuple as argument for command supporting ranges (cf. `MPD protocol documentation`_ for more details).
-Possible ranges are: "START:END", "START:" and ":" :
+Some commands (e.g. delete) allow specifying a range in the form `"START:END"` (cf. `MPD protocol documentation`_ for more details).
+
+Possible ranges are: `"START:END"`, `"START:"` and `":"` :
+
+Instead of giving the plain string as `"START:END"`, you **can** provide a :py:obj:`tuple` as `(START,END)`. The module is then ensuring the format is correct and raises an :py:obj:`musicpd.CommandError` exception otherwise. Empty start or end can be specified as en empty string ``''`` or :py:obj:`None`.
.. code-block:: python
# An intelligent clear
# clears played track in the queue, currentsong included
pos = client.currentsong().get('pos', 0)
- # the 2-tuple range object accepts str, no need to convert to int
+ # the range object accepts str, no need to convert to int
client.delete((0, pos))
# missing end interpreted as highest value possible, pay attention still need a tuple.
client.delete((pos,)) # purge queue from current to the end
-A notable case is the `rangeid` command allowing an empty range specified
-as a single colon as argument (i.e. sending just ":"):
+A notable case is the *rangeid* command allowing an empty range specified
+as a single colon as argument (i.e. sending just ``":"``):
.. code-block:: python
Empty start in range (i.e. ":END") are not possible and will raise a CommandError.
+.. note:: Remember the use of a tuple is **optional**. Range can still be specified as a plain string ``"START:END"``.
+
Iterators
----------
>>> print('something went wrong', file=sys.stderr)
>>> cli.disconnect()
-A `CommandError` is raised if the album does not expose a cover.
+A :py:obj:`musicpd.CommandError` is raised if the album does not expose a cover.
You can also use `readpicture` command to fetch embedded picture:
could also be that MPD took too much time to answer, but MPD taking more than a
couple of seconds for these commands should never occur).
+.. _exceptions:
+
+Exceptions
+----------
+
+The :py:obj:`connect<musicpd.MPDClient.connect>` method raises
+:py:obj:`ConnectionError<musicpd.ConnectionError>` only (an :py:obj:`MPDError<musicpd.MPDError>` exception) but then, calling other MPD commands, the module can raise
+:py:obj:`MPDError<musicpd.MPDError>` or an :py:obj:`OSError` depending on the error and
+where it occurs.
+
+Then using musicpd module both :py:obj:`musicpd.MPDError` and :py:obj:`OSError`
+exceptions families are expected, see :ref:`examples<exceptions_example>` for a
+way to deal with this.
.. _MPD protocol documentation: http://www.musicpd.org/doc/protocol/
+.. _snake case: https://en.wikipedia.org/wiki/Snake_case
.. vim: spell spelllang=en
home / dev / repositories / python-musicpd.git / blobdiff