Source code for mopidy.mpd.dispatcher

from __future__ import absolute_import, unicode_literals

import logging
import re

import pykka

from mopidy.mpd import exceptions, protocol, tokenize

logger = logging.getLogger(__name__)

protocol.load_protocol_modules()


[docs]class MpdDispatcher(object): """ The MPD session feeds the MPD dispatcher with requests. The dispatcher finds the correct handler, processes the request and sends the response back to the MPD session. """ _noidle = re.compile(r'^noidle$') def __init__(self, session=None, config=None, core=None, uri_map=None): self.config = config self.authenticated = False self.command_list_receiving = False self.command_list_ok = False self.command_list = [] self.command_list_index = None self.context = MpdContext( self, session=session, config=config, core=core, uri_map=uri_map)
[docs] def handle_request(self, request, current_command_list_index=None): """Dispatch incoming requests to the correct handler.""" self.command_list_index = current_command_list_index response = [] filter_chain = [ self._catch_mpd_ack_errors_filter, self._authenticate_filter, self._command_list_filter, self._idle_filter, self._add_ok_filter, self._call_handler_filter, ] return self._call_next_filter(request, response, filter_chain)
def handle_idle(self, subsystem): # TODO: validate against mopidy/mpd/protocol/status.SUBSYSTEMS self.context.events.add(subsystem) subsystems = self.context.subscriptions.intersection( self.context.events) if not subsystems: return response = [] for subsystem in subsystems: response.append('changed: %s' % subsystem) response.append('OK') self.context.subscriptions = set() self.context.events = set() self.context.session.send_lines(response) def _call_next_filter(self, request, response, filter_chain): if filter_chain: next_filter = filter_chain.pop(0) return next_filter(request, response, filter_chain) else: return response # Filter: catch MPD ACK errors def _catch_mpd_ack_errors_filter(self, request, response, filter_chain): try: return self._call_next_filter(request, response, filter_chain) except exceptions.MpdAckError as mpd_ack_error: if self.command_list_index is not None: mpd_ack_error.index = self.command_list_index return [mpd_ack_error.get_mpd_ack()] # Filter: authenticate def _authenticate_filter(self, request, response, filter_chain): if self.authenticated: return self._call_next_filter(request, response, filter_chain) elif self.config['mpd']['password'] is None: self.authenticated = True return self._call_next_filter(request, response, filter_chain) else: command_name = request.split(' ')[0] command = protocol.commands.handlers.get(command_name) if command and not command.auth_required: return self._call_next_filter(request, response, filter_chain) else: raise exceptions.MpdPermissionError(command=command_name) # Filter: command list def _command_list_filter(self, request, response, filter_chain): if self._is_receiving_command_list(request): self.command_list.append(request) return [] else: response = self._call_next_filter(request, response, filter_chain) if (self._is_receiving_command_list(request) or self._is_processing_command_list(request)): if response and response[-1] == 'OK': response = response[:-1] return response def _is_receiving_command_list(self, request): return ( self.command_list_receiving and request != 'command_list_end') def _is_processing_command_list(self, request): return ( self.command_list_index is not None and request != 'command_list_end') # Filter: idle def _idle_filter(self, request, response, filter_chain): if self._is_currently_idle() and not self._noidle.match(request): logger.debug( 'Client sent us %s, only %s is allowed while in ' 'the idle state', repr(request), repr('noidle')) self.context.session.close() return [] if not self._is_currently_idle() and self._noidle.match(request): return [] # noidle was called before idle response = self._call_next_filter(request, response, filter_chain) if self._is_currently_idle(): return [] else: return response def _is_currently_idle(self): return bool(self.context.subscriptions) # Filter: add OK def _add_ok_filter(self, request, response, filter_chain): response = self._call_next_filter(request, response, filter_chain) if not self._has_error(response): response.append('OK') return response def _has_error(self, response): return response and response[-1].startswith('ACK') # Filter: call handler def _call_handler_filter(self, request, response, filter_chain): try: response = self._format_response(self._call_handler(request)) return self._call_next_filter(request, response, filter_chain) except pykka.ActorDeadError as e: logger.warning('Tried to communicate with dead actor.') raise exceptions.MpdSystemError(e) def _call_handler(self, request): tokens = tokenize.split(request) # TODO: check that blacklist items are valid commands? blacklist = self.config['mpd'].get('command_blacklist', []) if tokens and tokens[0] in blacklist: logger.warning( 'MPD client used blacklisted command: %s', tokens[0]) raise exceptions.MpdDisabled(command=tokens[0]) try: return protocol.commands.call(tokens, context=self.context) except exceptions.MpdAckError as exc: if exc.command is None: exc.command = tokens[0] raise def _format_response(self, response): formatted_response = [] for element in self._listify_result(response): formatted_response.extend(self._format_lines(element)) return formatted_response def _listify_result(self, result): if result is None: return [] if isinstance(result, set): return self._flatten(list(result)) if not isinstance(result, list): return [result] return self._flatten(result) def _flatten(self, the_list): result = [] for element in the_list: if isinstance(element, list): result.extend(self._flatten(element)) else: result.append(element) return result def _format_lines(self, line): if isinstance(line, dict): return [ '{}: {}'.format(key, value) for (key, value) in line.items()] if isinstance(line, tuple): (key, value) = line return ['{}: {}'.format(key, value)] return [line]
[docs]class MpdContext(object): """ This object is passed as the first argument to all MPD command handlers to give the command handlers access to important parts of Mopidy. """ #: The current :class:`MpdDispatcher`. dispatcher = None #: The current :class:`mopidy.mpd.MpdSession`. session = None #: The MPD password password = None #: The Mopidy core API. An instance of :class:`mopidy.core.Core`. core = None #: The active subsystems that have pending events. events = None #: The subsytems that we want to be notified about in idle mode. subscriptions = None _uri_map = None def __init__(self, dispatcher, session=None, config=None, core=None, uri_map=None): self.dispatcher = dispatcher self.session = session if config is not None: self.password = config['mpd']['password'] self.core = core self.events = set() self.subscriptions = set() self._uri_map = uri_map
[docs] def lookup_playlist_uri_from_name(self, name): """ Helper function to retrieve a playlist from its unique MPD name. """ return self._uri_map.playlist_uri_from_name(name)
[docs] def lookup_playlist_name_from_uri(self, uri): """ Helper function to retrieve the unique MPD playlist name from its uri. """ return self._uri_map.playlist_name_from_uri(uri)
[docs] def browse(self, path, recursive=True, lookup=True): """ Browse the contents of a given directory path. Returns a sequence of two-tuples ``(path, data)``. If ``recursive`` is true, it returns results for all entries in the given path. If ``lookup`` is true and the ``path`` is to a track, the returned ``data`` is a future which will contain the results from looking up the URI with :meth:`mopidy.core.LibraryController.lookup`. If ``lookup`` is false and the ``path`` is to a track, the returned ``data`` will be a :class:`mopidy.models.Ref` for the track. For all entries that are not tracks, the returned ``data`` will be :class:`None`. """ path_parts = re.findall(r'[^/]+', path or '') root_path = '/'.join([''] + path_parts) uri = self._uri_map.uri_from_name(root_path) if uri is None: for part in path_parts: for ref in self.core.library.browse(uri).get(): if ref.type != ref.TRACK and ref.name == part: uri = ref.uri break else: raise exceptions.MpdNoExistError('Not found') root_path = self._uri_map.insert(root_path, uri) if recursive: yield (root_path, None) path_and_futures = [(root_path, self.core.library.browse(uri))] while path_and_futures: base_path, future = path_and_futures.pop() for ref in future.get(): path = '/'.join([base_path, ref.name.replace('/', '')]) path = self._uri_map.insert(path, ref.uri) if ref.type == ref.TRACK: if lookup: # TODO: can we lookup all the refs at once now? yield (path, self.core.library.lookup(uris=[ref.uri])) else: yield (path, ref) else: yield (path, None) if recursive: path_and_futures.append( (path, self.core.library.browse(ref.uri)))