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     print('Failed to import asyncio, need python >= 3.4')
  23
  24 import sys
  25
  26 HELLO_PREFIX = "OK MPD "
  27 ERROR_PREFIX = "ACK "
  28 SUCCESS = "OK"
  29 NEXT = "list_OK"
  30 VERSION = '0.0.1b'
  31
  32
  33 class MPDError(Exception):
  34     pass
  35
  36 class ConnectionError(MPDError):
  37     pass
  38
  39 class ProtocolError(MPDError):
  40     pass
  41
  42 class CommandError(MPDError):
  43     pass
  44
  45 class CommandListError(MPDError):
  46     pass
  47
  48 class PendingCommandError(MPDError):
  49     pass
  50
  51 class IteratingError(MPDError):
  52     pass
  53
  54
  55 class Response:
  56     def __init__(self):
  57         self.version = None
  58         self.resp = ''
  59         self.err = None
  60
  61     def __repr__(self):
  62         return 'err:{0}, "{1}…" ({2})'.format(
  63                 self.err,
  64                 ' '.join(self.resp.split('\n')[:2]),
  65                 self.version)
  66
  67 class MPDProto(asyncio.Protocol):
  68     def __init__(self, future, payload, cred):
  69         self.transport = None
  70         self.future = future
  71         self.payload = payload
  72         self.sess = Response()
  73
  74     def connection_made(self, transport):
  75         self.transport = transport
  76         self.transport.write(bytes('{}\n'.format(self.payload), 'utf-8'))
  77
  78     def eof_received(self):
  79         self.transport.close()
  80         err = ConnectionError('Connection lost while reading line')
  81         self.future.set_exception(err)
  82
  83     #def connection_lost(self):
  84     #    self.eof_received()
  85
  86     def data_received(self, data):
  87         rcv = self._hello(data.decode('utf-8'))
  88
  89         if rcv.startswith(ERROR_PREFIX):
  90             err = rcv[len(ERROR_PREFIX):].strip()
  91             self.future.set_exception(CommandError(err))
  92
  93         self.sess.resp += rcv
  94         if rcv.endswith(SUCCESS+'\n'):
  95             self.transport.close()
  96             self.future.set_result(self.sess)
  97
  98     def _hello(self, rcv):
  99         """Consume HELLO_PREFIX"""
 100
 101         if rcv.startswith(HELLO_PREFIX):
 102             self.sess.version = rcv.split('\n')[0][len(HELLO_PREFIX):]
 103             #print('consumed hello prefix: %s' % self.sess.version)
 104             return rcv[rcv.find('\n')+1:]
 105         return rcv
 106
 107 class MPDClient:
 108     loop = asyncio.get_event_loop()
 109
 110     def __init__(self, host='localhost', port=6600, cred=None):
 111         self._host = host
 112         self._port = port
 113         self._cred = cred
 114         self._commands = {
 115                 'currentsong',
 116                 'stats',
 117                 'playlistinfo',
 118         }
 119
 120     def __getattr__(self, attr):
 121         command = attr
 122         wrapper = self._command
 123         if command not in self._commands:
 124             command = command.replace("_", " ")
 125             if command not in self._commands:
 126                 raise AttributeError("'%s' object has no attribute '%s'" %
 127                                      (self.__class__.__name__, attr))
 128         return lambda *args: wrapper(command, args)
 129
 130     def _command(self, command, args):
 131         payload = '{} {}'.format(command ,''.join(args))
 132         future = asyncio.Future()
 133         # kick off a task to create the connection to MPD.
 134         asyncio.async(MPDClient.loop.create_connection(
 135                                     lambda: MPDProto(future, payload, self._cred),
 136                                     host=self._host,
 137                                     port=self._port))
 138         MPDClient.loop.run_until_complete(future)
 139         #Useless?
 140         #if future.exception():
 141         #    raise future.exception()
 142         # return once completed.
 143         return future.result().resp