musicpd.py

   1 # python-musicpd: Python MPD client library
   2 # Copyright (C) 2008-2010  J. Alexander Treuman <jat@spatialrift.net>
   3 # Copyright (C) 2012-2013  Kaliko Jack <kaliko@azylum.org>
   4 #
   5 # python-musicpd is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU Lesser General Public License as published by
   7 # the Free Software Foundation, either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # python-musicpd is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU Lesser General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU Lesser General Public License
  16 # along with python-musicpd.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 # pylint: disable=C0111
  19
  20 import socket
  21
  22
  23 HELLO_PREFIX = "OK MPD "
  24 ERROR_PREFIX = "ACK "
  25 SUCCESS = "OK"
  26 NEXT = "list_OK"
  27 VERSION = '0.4.0'
  28
  29
  30 class MPDError(Exception):
  31     pass
  32
  33 class ConnectionError(MPDError):
  34     pass
  35
  36 class ProtocolError(MPDError):
  37     pass
  38
  39 class CommandError(MPDError):
  40     pass
  41
  42 class CommandListError(MPDError):
  43     pass
  44
  45 class PendingCommandError(MPDError):
  46     pass
  47
  48 class IteratingError(MPDError):
  49     pass
  50
  51 class Range:
  52
  53     def __init__(self, tpl):
  54         self.tpl = tpl
  55         self._check()
  56
  57     def __str__(self):
  58         if len(self.tpl) == 1:
  59             return '{0}:'.format(self.tpl[0])
  60         return '{0[0]}:{0[1]}'.format(self.tpl)
  61
  62     def __repr__(self):
  63         return 'Range({0})'.format(self.tpl)
  64
  65     def _check(self):
  66         if not isinstance(self.tpl, tuple):
  67             raise CommandError('Wrong type, provide a tuple')
  68         if len(self.tpl) not in [1, 2]:
  69             raise CommandError('length not in [1, 2]')
  70         for index in self.tpl:
  71             try:
  72                 index = int(index)
  73             except (TypeError, ValueError):
  74                 raise CommandError('Not a tuple of int')
  75
  76
  77 class _NotConnected:
  78     def __getattr__(self, attr):
  79         return self._dummy
  80
  81     def _dummy(*args):
  82         raise ConnectionError("Not connected")
  83
  84 class MPDClient:
  85     def __init__(self):
  86         self.iterate = False
  87         self._reset()
  88         self._commands = {
  89             # Status Commands
  90             "clearerror":         self._fetch_nothing,
  91             "currentsong":        self._fetch_object,
  92             "idle":               self._fetch_list,
  93             "noidle":             None,
  94             "status":             self._fetch_object,
  95             "stats":              self._fetch_object,
  96             # Playback Option Commands
  97             "consume":            self._fetch_nothing,
  98             "crossfade":          self._fetch_nothing,
  99             "mixrampdb":          self._fetch_nothing,
 100             "mixrampdelay":       self._fetch_nothing,
 101             "random":             self._fetch_nothing,
 102             "repeat":             self._fetch_nothing,
 103             "setvol":             self._fetch_nothing,
 104             "single":             self._fetch_nothing,
 105             "replay_gain_mode":   self._fetch_nothing,
 106             "replay_gain_status": self._fetch_item,
 107             "volume":             self._fetch_nothing,
 108             # Playback Control Commands
 109             "next":               self._fetch_nothing,
 110             "pause":              self._fetch_nothing,
 111             "play":               self._fetch_nothing,
 112             "playid":             self._fetch_nothing,
 113             "previous":           self._fetch_nothing,
 114             "seek":               self._fetch_nothing,
 115             "seekid":             self._fetch_nothing,
 116             "seekcur":            self._fetch_nothing,
 117             "stop":               self._fetch_nothing,
 118             # Playlist Commands
 119             "add":                self._fetch_nothing,
 120             "addid":              self._fetch_item,
 121             "clear":              self._fetch_nothing,
 122             "delete":             self._fetch_nothing,
 123             "deleteid":           self._fetch_nothing,
 124             "move":               self._fetch_nothing,
 125             "moveid":             self._fetch_nothing,
 126             "playlist":           self._fetch_playlist,
 127             "playlistfind":       self._fetch_songs,
 128             "playlistid":         self._fetch_songs,
 129             "playlistinfo":       self._fetch_songs,
 130             "playlistsearch":     self._fetch_songs,
 131             "plchanges":          self._fetch_songs,
 132             "plchangesposid":     self._fetch_changes,
 133             "shuffle":            self._fetch_nothing,
 134             "swap":               self._fetch_nothing,
 135             "swapid":             self._fetch_nothing,
 136             # Stored Playlist Commands
 137             "listplaylist":       self._fetch_list,
 138             "listplaylistinfo":   self._fetch_songs,
 139             "listplaylists":      self._fetch_playlists,
 140             "load":               self._fetch_nothing,
 141             "playlistadd":        self._fetch_nothing,
 142             "playlistclear":      self._fetch_nothing,
 143             "playlistdelete":     self._fetch_nothing,
 144             "playlistmove":       self._fetch_nothing,
 145             "rename":             self._fetch_nothing,
 146             "rm":                 self._fetch_nothing,
 147             "save":               self._fetch_nothing,
 148             # Database Commands
 149             "count":              self._fetch_object,
 150             "find":               self._fetch_songs,
 151             "findadd":            self._fetch_nothing,
 152             "list":               self._fetch_list,
 153             "listall":            self._fetch_database,
 154             "listallinfo":        self._fetch_database,
 155             "lsinfo":             self._fetch_database,
 156             "search":             self._fetch_songs,
 157             "searchadd":          self._fetch_nothing,
 158             "searchaddpl":        self._fetch_nothing,
 159             "update":             self._fetch_item,
 160             "rescan":             self._fetch_item,
 161             "readcomments":       self._fetch_object,
 162             # Sticker Commands
 163             "sticker get":        self._fetch_item,
 164             "sticker set":        self._fetch_nothing,
 165             "sticker delete":     self._fetch_nothing,
 166             "sticker list":       self._fetch_list,
 167             "sticker find":       self._fetch_songs,
 168             # Connection Commands
 169             "close":              None,
 170             "kill":               None,
 171             "password":           self._fetch_nothing,
 172             "ping":               self._fetch_nothing,
 173             # Audio Output Commands
 174             "disableoutput":      self._fetch_nothing,
 175             "enableoutput":       self._fetch_nothing,
 176             "toggleoutput":       self._fetch_nothing,
 177             "outputs":            self._fetch_outputs,
 178             # Reflection Commands
 179             "commands":           self._fetch_list,
 180             "notcommands":        self._fetch_list,
 181             "tagtypes":           self._fetch_list,
 182             "urlhandlers":        self._fetch_list,
 183             "decoders":           self._fetch_plugins,
 184             # Client to Client
 185             "subscribe":          self._fetch_nothing,
 186             "unsubscribe":        self._fetch_nothing,
 187             "channels":           self._fetch_list,
 188             "readmessages":       self._fetch_messages,
 189             "sendmessage":        self._fetch_nothing,
 190         }
 191
 192     def __getattr__(self, attr):
 193         if attr.startswith("send_"):
 194             command = attr.replace("send_", "", 1)
 195             wrapper = self._send
 196         elif attr.startswith("fetch_"):
 197             command = attr.replace("fetch_", "", 1)
 198             wrapper = self._fetch
 199         else:
 200             command = attr
 201             wrapper = self._execute
 202         if command not in self._commands:
 203             command = command.replace("_", " ")
 204             if command not in self._commands:
 205                 raise AttributeError("'%s' object has no attribute '%s'" %
 206                                      (self.__class__.__name__, attr))
 207         return lambda *args: wrapper(command, args)
 208
 209     def _send(self, command, args):
 210         if self._command_list is not None:
 211             raise CommandListError("Cannot use send_%s in a command list" %
 212                                    command.replace(" ", "_"))
 213         self._write_command(command, args)
 214         retval = self._commands[command]
 215         if retval is not None:
 216             self._pending.append(command)
 217
 218     def _fetch(self, command, args=None):
 219         if self._command_list is not None:
 220             raise CommandListError("Cannot use fetch_%s in a command list" %
 221                                    command.replace(" ", "_"))
 222         if self._iterating:
 223             raise IteratingError("Cannot use fetch_%s while iterating" %
 224                                  command.replace(" ", "_"))
 225         if not self._pending:
 226             raise PendingCommandError("No pending commands to fetch")
 227         if self._pending[0] != command:
 228             raise PendingCommandError("'%s' is not the currently "
 229                                       "pending command" % command)
 230         del self._pending[0]
 231         retval = self._commands[command]
 232         if callable(retval):
 233             return retval()
 234         return retval
 235
 236     def _execute(self, command, args):
 237         if self._iterating:
 238             raise IteratingError("Cannot execute '%s' while iterating" %
 239                                  command)
 240         if self._pending:
 241             raise PendingCommandError("Cannot execute '%s' with "
 242                                       "pending commands" % command)
 243         retval = self._commands[command]
 244         if self._command_list is not None:
 245             if not callable(retval):
 246                 raise CommandListError("'%s' not allowed in command list" %
 247                                         command)
 248             self._write_command(command, args)
 249             self._command_list.append(retval)
 250         else:
 251             self._write_command(command, args)
 252             if callable(retval):
 253                 return retval()
 254             return retval
 255
 256     def _write_line(self, line):
 257         self._wfile.write("%s\n" % line)
 258         self._wfile.flush()
 259
 260     def _write_command(self, command, args=None):
 261         if args is None:
 262             args = []
 263         parts = [command]
 264         for arg in args:
 265             if isinstance(arg, tuple):
 266                 parts.append('{0!s}'.format(Range(arg)))
 267             else:
 268                 parts.append('"%s"' % escape(str(arg)))
 269         self._write_line(" ".join(parts))
 270
 271     def _read_line(self):
 272         line = self._rfile.readline()
 273         if not line.endswith("\n"):
 274             self.disconnect()
 275             raise ConnectionError("Connection lost while reading line")
 276         line = line.rstrip("\n")
 277         if line.startswith(ERROR_PREFIX):
 278             error = line[len(ERROR_PREFIX):].strip()
 279             raise CommandError(error)
 280         if self._command_list is not None:
 281             if line == NEXT:
 282                 return
 283             if line == SUCCESS:
 284                 raise ProtocolError("Got unexpected '%s'" % SUCCESS)
 285         elif line == SUCCESS:
 286             return
 287         return line
 288
 289     def _read_pair(self, separator):
 290         line = self._read_line()
 291         if line is None:
 292             return
 293         pair = line.split(separator, 1)
 294         if len(pair) < 2:
 295             raise ProtocolError("Could not parse pair: '%s'" % line)
 296         return pair
 297
 298     def _read_pairs(self, separator=": "):
 299         pair = self._read_pair(separator)
 300         while pair:
 301             yield pair
 302             pair = self._read_pair(separator)
 303
 304     def _read_list(self):
 305         seen = None
 306         for key, value in self._read_pairs():
 307             if key != seen:
 308                 if seen is not None:
 309                     raise ProtocolError("Expected key '%s', got '%s'" %
 310                                         (seen, key))
 311                 seen = key
 312             yield value
 313
 314     def _read_playlist(self):
 315         for _, value in self._read_pairs(":"):
 316             yield value
 317
 318     def _read_objects(self, delimiters=None):
 319         obj = {}
 320         if delimiters is None:
 321             delimiters = []
 322         for key, value in self._read_pairs():
 323             key = key.lower()
 324             if obj:
 325                 if key in delimiters:
 326                     yield obj
 327                     obj = {}
 328                 elif key in obj:
 329                     if not isinstance(obj[key], list):
 330                         obj[key] = [obj[key], value]
 331                     else:
 332                         obj[key].append(value)
 333                     continue
 334             obj[key] = value
 335         if obj:
 336             yield obj
 337
 338     def _read_command_list(self):
 339         try:
 340             for retval in self._command_list:
 341                 yield retval()
 342         finally:
 343             self._command_list = None
 344         self._fetch_nothing()
 345
 346     def _iterator_wrapper(self, iterator):
 347         try:
 348             for item in iterator:
 349                 yield item
 350         finally:
 351             self._iterating = False
 352
 353     def _wrap_iterator(self, iterator):
 354         if not self.iterate:
 355             return list(iterator)
 356         self._iterating = True
 357         return self._iterator_wrapper(iterator)
 358
 359     def _fetch_nothing(self):
 360         line = self._read_line()
 361         if line is not None:
 362             raise ProtocolError("Got unexpected return value: '%s'" % line)
 363
 364     def _fetch_item(self):
 365         pairs = list(self._read_pairs())
 366         if len(pairs) != 1:
 367             return
 368         return pairs[0][1]
 369
 370     def _fetch_list(self):
 371         return self._wrap_iterator(self._read_list())
 372
 373     def _fetch_playlist(self):
 374         return self._wrap_iterator(self._read_playlist())
 375
 376     def _fetch_object(self):
 377         objs = list(self._read_objects())
 378         if not objs:
 379             return {}
 380         return objs[0]
 381
 382     def _fetch_objects(self, delimiters):
 383         return self._wrap_iterator(self._read_objects(delimiters))
 384
 385     def _fetch_changes(self):
 386         return self._fetch_objects(["cpos"])
 387
 388     def _fetch_songs(self):
 389         return self._fetch_objects(["file"])
 390
 391     def _fetch_playlists(self):
 392         return self._fetch_objects(["playlist"])
 393
 394     def _fetch_database(self):
 395         return self._fetch_objects(["file", "directory", "playlist"])
 396
 397     def _fetch_outputs(self):
 398         return self._fetch_objects(["outputid"])
 399
 400     def _fetch_plugins(self):
 401         return self._fetch_objects(["plugin"])
 402
 403     def _fetch_messages(self):
 404         return self._fetch_objects(["channel"])
 405
 406     def _fetch_command_list(self):
 407         return self._wrap_iterator(self._read_command_list())
 408
 409     def _hello(self):
 410         line = self._rfile.readline()
 411         if not line.endswith("\n"):
 412             raise ConnectionError("Connection lost while reading MPD hello")
 413         line = line.rstrip("\n")
 414         if not line.startswith(HELLO_PREFIX):
 415             raise ProtocolError("Got invalid MPD hello: '%s'" % line)
 416         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 417
 418     def _reset(self):
 419         # pylint: disable=w0201
 420         self.mpd_version = None
 421         self._iterating = False
 422         self._pending = []
 423         self._command_list = None
 424         self._sock = None
 425         self._rfile = _NotConnected()
 426         self._wfile = _NotConnected()
 427
 428     def _connect_unix(self, path):
 429         if not hasattr(socket, "AF_UNIX"):
 430             raise ConnectionError("Unix domain sockets not supported "
 431                                   "on this platform")
 432         sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
 433         sock.connect(path)
 434         return sock
 435
 436     def _connect_tcp(self, host, port):
 437         try:
 438             flags = socket.AI_ADDRCONFIG
 439         except AttributeError:
 440             flags = 0
 441         err = None
 442         for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
 443                                       socket.SOCK_STREAM, socket.IPPROTO_TCP,
 444                                       flags):
 445             af, socktype, proto, _, sa = res
 446             sock = None
 447             try:
 448                 sock = socket.socket(af, socktype, proto)
 449                 sock.connect(sa)
 450                 return sock
 451             except socket.error as socket_err:
 452                 err = socket_err
 453                 if sock is not None:
 454                     sock.close()
 455         if err is not None:
 456             raise ConnectionError(str(err))
 457         else:
 458             raise ConnectionError("getaddrinfo returns an empty list")
 459
 460     def connect(self, host, port):
 461         if self._sock is not None:
 462             raise ConnectionError("Already connected")
 463         if host.startswith("/"):
 464             self._sock = self._connect_unix(host)
 465         else:
 466             self._sock = self._connect_tcp(host, port)
 467         self._rfile = self._sock.makefile("r", encoding='utf-8')
 468         self._wfile = self._sock.makefile("w", encoding='utf-8')
 469         try:
 470             self._hello()
 471         except:
 472             self.disconnect()
 473             raise
 474
 475     def disconnect(self):
 476         if hasattr(self._rfile, 'close'):
 477             self._rfile.close()
 478         if hasattr(self._wfile, 'close'):
 479             self._wfile.close()
 480         if hasattr(self._sock, 'close'):
 481             self._sock.close()
 482         self._reset()
 483
 484     def fileno(self):
 485         if self._sock is None:
 486             raise ConnectionError("Not connected")
 487         return self._sock.fileno()
 488
 489     def command_list_ok_begin(self):
 490         if self._command_list is not None:
 491             raise CommandListError("Already in command list")
 492         if self._iterating:
 493             raise IteratingError("Cannot begin command list while iterating")
 494         if self._pending:
 495             raise PendingCommandError("Cannot begin command list "
 496                                       "with pending commands")
 497         self._write_command("command_list_ok_begin")
 498         self._command_list = []
 499
 500     def command_list_end(self):
 501         if self._command_list is None:
 502             raise CommandListError("Not in command list")
 503         if self._iterating:
 504             raise IteratingError("Already iterating over a command list")
 505         self._write_command("command_list_end")
 506         return self._fetch_command_list()
 507
 508
 509 def escape(text):
 510     return text.replace("\\", "\\\\").replace('"', '\\"')
 511
 512
 513 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: