musicpdasio.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # python-musicpd: Python MPD client library
   4 # Copyright (C) 2014-2015  Kaliko Jack <kaliko@azylum.org>
   5 #
   6 # python-musicpdasio is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU Lesser General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # python-musicpd is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU Lesser General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU Lesser General Public License
  17 # along with python-musicpd.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 try:
  20     import asyncio
  21 except ImportError:
  22     import sys
  23     print('Failed to import asyncio, need python >= 3.4')
  24     sys.exit(1)
  25
  26 import logging
  27
  28 from os import environ
  29 if 'DEBUG' in environ or 'PYTHONASYNCIODEBUG' in environ:
  30     logging.basicConfig(level=logging.DEBUG)
  31
  32 HELLO_PREFIX = "OK MPD "
  33 ERROR_PREFIX = "ACK "
  34 SUCCESS = "OK"
  35 NEXT = "list_OK"
  36 VERSION = '0.0.1b'
  37
  38
  39 class MPDError(Exception):
  40     pass
  41
  42 class ConnectionError(MPDError):
  43     pass
  44
  45 class ProtocolError(MPDError):
  46     pass
  47
  48 class CommandError(MPDError):
  49     pass
  50
  51 class CommandListError(MPDError):
  52     pass
  53
  54 class PendingCommandError(MPDError):
  55     pass
  56
  57 class IteratingError(MPDError):
  58     pass
  59
  60
  61 class Response:
  62     def __init__(self):
  63         self.version = None
  64         self.resp = ''
  65
  66     def __repr__(self):
  67         return '"{0}…" ({1})'.format(
  68                 ' '.join(self.resp.split('\n')[:2]),
  69                 self.version)
  70
  71 class MPDProto(asyncio.Protocol):
  72     def __init__(self, future, payload, cred):
  73         self.transport = None
  74         self.future = future
  75         self.payload = payload
  76         self.sess = Response()
  77
  78     def connection_made(self, transport):
  79         self.transport = transport
  80         self.transport.write(bytes('{}\n'.format(self.payload), 'utf-8'))
  81
  82     def eof_received(self):
  83         self.transport.close()
  84         err = ConnectionError('Connection lost while reading line')
  85         self.future.set_exception(err)
  86
  87     def data_received(self, data):
  88         #logging.debug(data.decode('utf-8'))
  89         rcv = self._hello(data.decode('utf-8'))
  90
  91         if rcv.startswith(ERROR_PREFIX):
  92             err = rcv[len(ERROR_PREFIX):].strip()
  93             self.future.set_exception(CommandError(err))
  94
  95         self.sess.resp += rcv
  96         if rcv.endswith(SUCCESS+'\n'):
  97             logging.debug('set future result')
  98             self.transport.close()
  99             self.future.set_result(self.sess)
 100
 101     def _hello(self, rcv):
 102         """Consume HELLO_PREFIX"""
 103         if rcv.startswith(HELLO_PREFIX):
 104             logging.debug('consumed hello prefix')
 105             self.sess.version = rcv.split('\n')[0][len(HELLO_PREFIX):]
 106             return rcv[rcv.find('\n')+1:]
 107         return rcv
 108
 109 class MPDClient:
 110
 111     def __init__(self, host='localhost', port=6600, cred=None):
 112         self.eloop = asyncio.get_event_loop()
 113         self.asio = False
 114         self.futures = []
 115         self._host = host
 116         self._port = port
 117         self._cred = cred
 118         self._commands = {
 119                 'currentsong',
 120                 'stats',
 121                 'playlistinfo',
 122         }
 123
 124     def __getattr__(self, attr):
 125         #logging.debug(attr)
 126         command = attr
 127         wrapper = self._command
 128         if command not in self._commands:
 129             command = command.replace("_", " ")
 130             if command not in self._commands:
 131                 raise AttributeError("'%s' object has no attribute '%s'" %
 132                                      (self.__class__.__name__, attr))
 133         return lambda *args: wrapper(command, args)
 134
 135     @asyncio.coroutine
 136     def _connect(self, proto):
 137         # coroutine allowing Exception handling
 138         # src: http://comments.gmane.org/gmane.comp.python.tulip/1401
 139         try:
 140             yield from self.eloop.create_connection(lambda: proto,
 141                     host=self._host,
 142                     port=self._port)
 143         except Exception as err:
 144             proto.future.set_exception(ConnectionError(err))
 145
 146     def _command(self, command, args):
 147         payload = '{} {}'.format(command, ''.join(args))
 148         future = asyncio.Future()
 149         # kick off a task to create the connection to MPD
 150         coro = self._connect(MPDProto(future, payload, self._cred))
 151         asyncio.async(coro)
 152         self.futures.append(future)
 153         if not self.asio:
 154             # return once completed.
 155             self.eloop.run_until_complete(future)
 156         return future
 157         # alternative w/ callback
 158         #if not self.asio:
 159         #    future.add_done_callback(lambda ftr: MPDClient.loop.stop())
 160         #    self.eloop.run_forever()
 161         #return future
 162
 163     def run(self):
 164         if self.futures:
 165            self.eloop.run_until_complete(asyncio.gather(*self.futures))
 166            self.futures = []
 167         else:
 168             logging.info('No task found in queue, need to set self.asio?')