X-Git-Url: https://git.kaliko.me/?a=blobdiff_plain;f=doc%2Fsource%2Fuse.rst;h=119de2dfc975cc69f4762bba5ffa347c856e470a;hb=43efcdd63b071ef5a5224fec37ebf298cfacd0f9;hp=cdf0ed223effa1dcf53066685a7c5dc33b05a68c;hpb=0c16ca07e3ac85ab212c3444f9e5a71c4a96a406;p=python-musicpd.git diff --git a/doc/source/use.rst b/doc/source/use.rst index cdf0ed2..119de2d 100644 --- a/doc/source/use.rst +++ b/doc/source/use.rst @@ -1,3 +1,6 @@ +.. SPDX-FileCopyrightText: 2018-2023 kaliko +.. SPDX-License-Identifier: LGPL-3.0-or-later + Using the client library ========================= @@ -13,38 +16,94 @@ The client library can be used as follows: # 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`. -See the `MPD protocol documentation`_ for more details. +For more about the protocol and MPD commands see the `MPD protocol +documentation`_. + +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 + +.. envvar:: MPD_TIMEOUT + + socket timeout when connecting to MPD and waiting for MPD’s response (in seconds) - * ``MPD_HOST`` MPD host (:abbr:`FQDN (fully qualified domain name)`, socket path or abstract socket) and password. +.. envvar:: XDG_RUNTIME_DIR - | 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`` + path to look for potential socket -Defaults settings ------------------ +.. _default_settings: - * If ``MPD_HOST`` is not set, then look for a socket in ``${XDG_RUNTIME_DIR}/mpd/socket`` - * If there is no socket use ``localhost`` - * If ``MPD_PORT`` is not set, then use ``6600`` - * If ``MPD_TIMEOUT`` is not set, then uses :py:obj:`musicpd.CONNECTION_TIMEOUT` +Default settings +---------------- + +Default host: + * use :envvar:`MPD_HOST` environment variable if set, extract password if present, + * else looks for an existing file in :envvar:`${XDG_RUNTIME_DIR:-/run/}/mpd/socket` + * else set host to ``localhost`` + +Default port: + * use :envvar:`MPD_PORT` environment variable is set + * else use ``6600`` + +Default timeout: + * use :envvar:`MPD_TIMEOUT` is set + * else use :py:obj:`musicpd.CONNECTION_TIMEOUT` + +Context manager +--------------- + +Calling MPDClient in a context manager :py:obj:`musicpd.MPDClient.connect` is +transparently called with :ref:`default setting` (use +:ref:`environment variables` to override defaults). +Leaving the context manager :py:obj:`musicpd.MPDClient.disconnect` is called. + +.. code-block:: python + + import os + os.environ['MPD_HOST'] = 'mpdhost' + with MPDClient() as c: + c.status() + c.next() Command lists ------------- @@ -62,21 +121,24 @@ Command lists are also supported using `command_list_ok_begin()` and 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 @@ -85,6 +147,8 @@ as a single colon as argument (i.e. sending just ":"): Empty start in range (i.e. ":END") are not possible and will raise a CommandError. +Remember the of the tuple is optional, range can still be specified as single string ``"START:END"``. + Iterators ---------- @@ -101,7 +165,7 @@ Idle prefixed commands ---------------------- Each command have a *send\_* and a *fetch\_* variant, which allows to -send a MPD command and then fetch the result later. +send a MPD command and then fetch the result later (non-blocking call). This is useful for the idle command: .. code-block:: python @@ -122,6 +186,8 @@ This is useful for the idle command: >>> gobject.io_add_watch(client, gobject.IO_IN, callback) >>> gobject.MainLoop().run() +See also use of :ref:`socket timeout` with idle command. + Fetching binary content (cover art) ----------------------------------- @@ -172,6 +238,8 @@ You can also use `readpicture` command to fetch embedded picture: Refer to `MPD protocol documentation`_ for the meaning of `binary`, `size` and `data`. +.. _socket_timeout: + Socket timeout -------------- @@ -218,6 +286,10 @@ Here is a solution to use ``idle`` command with ``socket_timeout``: cli.noidle() except socket.timeout as err: print(f'{err} (timeout {cli.socket_timeout})') + except (OSError, musicpd.MPDError) as err: + print(f'{err!r}') + if cli._sock is not None: + cli.disconnect() except KeyboardInterrupt: pass @@ -232,8 +304,10 @@ Some explanations: All three commands in the while loop (send_idle, fetch_idle, noidle) are not triggering a socket timeout unless the connection is actually lost (actually it -could also be that MPD took to much time to answer, but MPD taking more than a +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). .. _MPD protocol documentation: http://www.musicpd.org/doc/protocol/ +.. _snake case: https://en.wikipedia.org/wiki/Snake_case +.. vim: spell spelllang=en