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 = '0.4.0pr2'
  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=[]):
 261         parts = [command]
 262         for arg in args:
 263             if isinstance(arg, tuple):
 264                 parts.append('{0!s}'.format(Range(arg)))
 265             else:
 266                 parts.append('"%s"' % escape(str(arg)))
 267         self._write_line(" ".join(parts))
 268
 269     def _read_line(self):
 270         line = self._rfile.readline()
 271         if not line.endswith("\n"):
 272             self.disconnect()
 273             raise ConnectionError("Connection lost while reading line")
 274         line = line.rstrip("\n")
 275         if line.startswith(ERROR_PREFIX):
 276             error = line[len(ERROR_PREFIX):].strip()
 277             raise CommandError(error)
 278         if self._command_list is not None:
 279             if line == NEXT:
 280                 return
 281             if line == SUCCESS:
 282                 raise ProtocolError("Got unexpected '%s'" % SUCCESS)
 283         elif line == SUCCESS:
 284             return
 285         return line
 286
 287     def _read_pair(self, separator):
 288         line = self._read_line()
 289         if line is None:
 290             return
 291         pair = line.split(separator, 1)
 292         if len(pair) < 2:
 293             raise ProtocolError("Could not parse pair: '%s'" % line)
 294         return pair
 295
 296     def _read_pairs(self, separator=": "):
 297         pair = self._read_pair(separator)
 298         while pair:
 299             yield pair
 300             pair = self._read_pair(separator)
 301
 302     def _read_list(self):
 303         seen = None
 304         for key, value in self._read_pairs():
 305             if key != seen:
 306                 if seen is not None:
 307                     raise ProtocolError("Expected key '%s', got '%s'" %
 308                                         (seen, key))
 309                 seen = key
 310             yield value
 311
 312     def _read_playlist(self):
 313         for key, value in self._read_pairs(":"):
 314             yield value
 315
 316     def _read_objects(self, delimiters=[]):
 317         obj = {}
 318         for key, value in self._read_pairs():
 319             key = key.lower()
 320             if obj:
 321                 if key in delimiters:
 322                     yield obj
 323                     obj = {}
 324                 elif key in obj:
 325                     if not isinstance(obj[key], list):
 326                         obj[key] = [obj[key], value]
 327                     else:
 328                         obj[key].append(value)
 329                     continue
 330             obj[key] = value
 331         if obj:
 332             yield obj
 333
 334     def _read_command_list(self):
 335         try:
 336             for retval in self._command_list:
 337                 yield retval()
 338         finally:
 339             self._command_list = None
 340         self._fetch_nothing()
 341
 342     def _iterator_wrapper(self, iterator):
 343         try:
 344             for item in iterator:
 345                 yield item
 346         finally:
 347             self._iterating = False
 348
 349     def _wrap_iterator(self, iterator):
 350         if not self.iterate:
 351             return list(iterator)
 352         self._iterating = True
 353         return self._iterator_wrapper(iterator)
 354
 355     def _fetch_nothing(self):
 356         line = self._read_line()
 357         if line is not None:
 358             raise ProtocolError("Got unexpected return value: '%s'" % line)
 359
 360     def _fetch_item(self):
 361         pairs = list(self._read_pairs())
 362         if len(pairs) != 1:
 363             return
 364         return pairs[0][1]
 365
 366     def _fetch_list(self):
 367         return self._wrap_iterator(self._read_list())
 368
 369     def _fetch_playlist(self):
 370         return self._wrap_iterator(self._read_playlist())
 371
 372     def _fetch_object(self):
 373         objs = list(self._read_objects())
 374         if not objs:
 375             return {}
 376         return objs[0]
 377
 378     def _fetch_objects(self, delimiters):
 379         return self._wrap_iterator(self._read_objects(delimiters))
 380
 381     def _fetch_changes(self):
 382         return self._fetch_objects(["cpos"])
 383
 384     def _fetch_songs(self):
 385         return self._fetch_objects(["file"])
 386
 387     def _fetch_playlists(self):
 388         return self._fetch_objects(["playlist"])
 389
 390     def _fetch_database(self):
 391         return self._fetch_objects(["file", "directory", "playlist"])
 392
 393     def _fetch_outputs(self):
 394         return self._fetch_objects(["outputid"])
 395
 396     def _fetch_plugins(self):
 397         return self._fetch_objects(["plugin"])
 398
 399     def _fetch_messages(self):
 400         return self._fetch_objects(["channel"])
 401
 402     def _fetch_command_list(self):
 403         return self._wrap_iterator(self._read_command_list())
 404
 405     def _hello(self):
 406         line = self._rfile.readline()
 407         if not line.endswith("\n"):
 408             raise ConnectionError("Connection lost while reading MPD hello")
 409         line = line.rstrip("\n")
 410         if not line.startswith(HELLO_PREFIX):
 411             raise ProtocolError("Got invalid MPD hello: '%s'" % line)
 412         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 413
 414     def _reset(self):
 415         # pylint: disable=w0201
 416         self.mpd_version = None
 417         self._iterating = False
 418         self._pending = []
 419         self._command_list = None
 420         self._sock = None
 421         self._rfile = _NotConnected()
 422         self._wfile = _NotConnected()
 423
 424     def _connect_unix(self, path):
 425         if not hasattr(socket, "AF_UNIX"):
 426             raise ConnectionError("Unix domain sockets not supported "
 427                                   "on this platform")
 428         sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
 429         sock.connect(path)
 430         return sock
 431
 432     def _connect_tcp(self, host, port):
 433         try:
 434             flags = socket.AI_ADDRCONFIG
 435         except AttributeError:
 436             flags = 0
 437         err = None
 438         for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
 439                                       socket.SOCK_STREAM, socket.IPPROTO_TCP,
 440                                       flags):
 441             af, socktype, proto, canonname, sa = res
 442             sock = None
 443             try:
 444                 sock = socket.socket(af, socktype, proto)
 445                 sock.connect(sa)
 446                 return sock
 447             except socket.error as socket_err:
 448                 err = socket_err
 449                 if sock is not None:
 450                     sock.close()
 451         if err is not None:
 452             raise ConnectionError(str(err))
 453         else:
 454             raise ConnectionError("getaddrinfo returns an empty list")
 455
 456     def connect(self, host, port):
 457         if self._sock is not None:
 458             raise ConnectionError("Already connected")
 459         if host.startswith("/"):
 460             self._sock = self._connect_unix(host)
 461         else:
 462             self._sock = self._connect_tcp(host, port)
 463         self._rfile = self._sock.makefile("r", encoding='utf-8')
 464         self._wfile = self._sock.makefile("w", encoding='utf-8')
 465         try:
 466             self._hello()
 467         except:
 468             self.disconnect()
 469             raise
 470
 471     def disconnect(self):
 472         if hasattr(self._rfile, 'close'):
 473             self._rfile.close()
 474         if hasattr(self._wfile, 'close'):
 475             self._wfile.close()
 476         if hasattr(self._sock, 'close'):
 477             self._sock.close()
 478         self._reset()
 479
 480     def fileno(self):
 481         if self._sock is None:
 482             raise ConnectionError("Not connected")
 483         return self._sock.fileno()
 484
 485     def command_list_ok_begin(self):
 486         if self._command_list is not None:
 487             raise CommandListError("Already in command list")
 488         if self._iterating:
 489             raise IteratingError("Cannot begin command list while iterating")
 490         if self._pending:
 491             raise PendingCommandError("Cannot begin command list "
 492                                       "with pending commands")
 493         self._write_command("command_list_ok_begin")
 494         self._command_list = []
 495
 496     def command_list_end(self):
 497         if self._command_list is None:
 498             raise CommandListError("Not in command list")
 499         if self._iterating:
 500             raise IteratingError("Already iterating over a command list")
 501         self._write_command("command_list_end")
 502         return self._fetch_command_list()
 503
 504
 505 def escape(text):
 506     return text.replace("\\", "\\\\").replace('"', '\\"')
 507
 508
 509 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: