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 import socket
  19
  20
  21 HELLO_PREFIX = "OK MPD "
  22 ERROR_PREFIX = "ACK "
  23 SUCCESS = "OK"
  24 NEXT = "list_OK"
  25 VERSION = '0.4.0pr0'
  26
  27
  28 class MPDError(Exception):
  29     pass
  30
  31 class ConnectionError(MPDError):
  32     pass
  33
  34 class ProtocolError(MPDError):
  35     pass
  36
  37 class CommandError(MPDError):
  38     pass
  39
  40 class CommandListError(MPDError):
  41     pass
  42
  43 class PendingCommandError(MPDError):
  44     pass
  45
  46 class IteratingError(MPDError):
  47     pass
  48
  49
  50 class _NotConnected(object):
  51     def __getattr__(self, attr):
  52         return self._dummy
  53
  54     def _dummy(*args):
  55         raise ConnectionError("Not connected")
  56
  57 class MPDClient(object):
  58     def __init__(self):
  59         self.iterate = False
  60         self._reset()
  61         self._commands = {
  62             # Status Commands
  63             "clearerror":         self._fetch_nothing,
  64             "currentsong":        self._fetch_object,
  65             "idle":               self._fetch_list,
  66             "noidle":             None,
  67             "status":             self._fetch_object,
  68             "stats":              self._fetch_object,
  69             # Playback Option Commands
  70             "consume":            self._fetch_nothing,
  71             "crossfade":          self._fetch_nothing,
  72             "mixrampdb":          self._fetch_nothing,
  73             "mixrampdelay":       self._fetch_nothing,
  74             "random":             self._fetch_nothing,
  75             "repeat":             self._fetch_nothing,
  76             "setvol":             self._fetch_nothing,
  77             "single":             self._fetch_nothing,
  78             "replay_gain_mode":   self._fetch_nothing,
  79             "replay_gain_status": self._fetch_item,
  80             "volume":             self._fetch_nothing,
  81             # Playback Control Commands
  82             "next":               self._fetch_nothing,
  83             "pause":              self._fetch_nothing,
  84             "play":               self._fetch_nothing,
  85             "playid":             self._fetch_nothing,
  86             "previous":           self._fetch_nothing,
  87             "seek":               self._fetch_nothing,
  88             "seekid":             self._fetch_nothing,
  89             "seekcur":            self._fetch_nothing,
  90             "stop":               self._fetch_nothing,
  91             # Playlist Commands
  92             "add":                self._fetch_nothing,
  93             "addid":              self._fetch_item,
  94             "clear":              self._fetch_nothing,
  95             "delete":             self._fetch_nothing,
  96             "deleteid":           self._fetch_nothing,
  97             "move":               self._fetch_nothing,
  98             "moveid":             self._fetch_nothing,
  99             "playlist":           self._fetch_playlist,
 100             "playlistfind":       self._fetch_songs,
 101             "playlistid":         self._fetch_songs,
 102             "playlistinfo":       self._fetch_songs,
 103             "playlistsearch":     self._fetch_songs,
 104             "plchanges":          self._fetch_songs,
 105             "plchangesposid":     self._fetch_changes,
 106             "shuffle":            self._fetch_nothing,
 107             "swap":               self._fetch_nothing,
 108             "swapid":             self._fetch_nothing,
 109             # Stored Playlist Commands
 110             "listplaylist":       self._fetch_list,
 111             "listplaylistinfo":   self._fetch_songs,
 112             "listplaylists":      self._fetch_playlists,
 113             "load":               self._fetch_nothing,
 114             "playlistadd":        self._fetch_nothing,
 115             "playlistclear":      self._fetch_nothing,
 116             "playlistdelete":     self._fetch_nothing,
 117             "playlistmove":       self._fetch_nothing,
 118             "rename":             self._fetch_nothing,
 119             "rm":                 self._fetch_nothing,
 120             "save":               self._fetch_nothing,
 121             # Database Commands
 122             "count":              self._fetch_object,
 123             "find":               self._fetch_songs,
 124             "findadd":            self._fetch_nothing,
 125             "list":               self._fetch_list,
 126             "listall":            self._fetch_database,
 127             "listallinfo":        self._fetch_database,
 128             "lsinfo":             self._fetch_database,
 129             "search":             self._fetch_songs,
 130             "searchadd":          self._fetch_nothing,
 131             "searchaddpl":        self._fetch_nothing,
 132             "update":             self._fetch_item,
 133             "rescan":             self._fetch_item,
 134             "readcomments":       self._fetch_object,
 135             # Sticker Commands
 136             "sticker get":        self._fetch_item,
 137             "sticker set":        self._fetch_nothing,
 138             "sticker delete":     self._fetch_nothing,
 139             "sticker list":       self._fetch_list,
 140             "sticker find":       self._fetch_songs,
 141             # Connection Commands
 142             "close":              None,
 143             "kill":               None,
 144             "password":           self._fetch_nothing,
 145             "ping":               self._fetch_nothing,
 146             # Audio Output Commands
 147             "disableoutput":      self._fetch_nothing,
 148             "enableoutput":       self._fetch_nothing,
 149             "toggleoutput":       self._fetch_nothing,
 150             "outputs":            self._fetch_outputs,
 151             # Reflection Commands
 152             "commands":           self._fetch_list,
 153             "notcommands":        self._fetch_list,
 154             "tagtypes":           self._fetch_list,
 155             "urlhandlers":        self._fetch_list,
 156             "decoders":           self._fetch_plugins,
 157             # Client to Client
 158             "subscribe":          self._fetch_nothing,
 159             "unsubscribe":        self._fetch_nothing,
 160             "channels":           self._fetch_list,
 161             "readmessages":       self._fetch_messages,
 162             "sendmessage":        self._fetch_nothing,
 163         }
 164
 165     def __getattr__(self, attr):
 166         if attr.startswith("send_"):
 167             command = attr.replace("send_", "", 1)
 168             wrapper = self._send
 169         elif attr.startswith("fetch_"):
 170             command = attr.replace("fetch_", "", 1)
 171             wrapper = self._fetch
 172         else:
 173             command = attr
 174             wrapper = self._execute
 175         if command not in self._commands:
 176             command = command.replace("_", " ")
 177             if command not in self._commands:
 178                 raise AttributeError("'%s' object has no attribute '%s'" %
 179                                      (self.__class__.__name__, attr))
 180         return lambda *args: wrapper(command, args)
 181
 182     def _send(self, command, args):
 183         if self._command_list is not None:
 184             raise CommandListError("Cannot use send_%s in a command list" %
 185                                    command.replace(" ", "_"))
 186         self._write_command(command, args)
 187         retval = self._commands[command]
 188         if retval is not None:
 189             self._pending.append(command)
 190
 191     def _fetch(self, command, args=None):
 192         if self._command_list is not None:
 193             raise CommandListError("Cannot use fetch_%s in a command list" %
 194                                    command.replace(" ", "_"))
 195         if self._iterating:
 196             raise IteratingError("Cannot use fetch_%s while iterating" %
 197                                  command.replace(" ", "_"))
 198         if not self._pending:
 199             raise PendingCommandError("No pending commands to fetch")
 200         if self._pending[0] != command:
 201             raise PendingCommandError("'%s' is not the currently "
 202                                       "pending command" % command)
 203         del self._pending[0]
 204         retval = self._commands[command]
 205         if callable(retval):
 206             return retval()
 207         return retval
 208
 209     def _execute(self, command, args):
 210         if self._iterating:
 211             raise IteratingError("Cannot execute '%s' while iterating" %
 212                                  command)
 213         if self._pending:
 214             raise PendingCommandError("Cannot execute '%s' with "
 215                                       "pending commands" % command)
 216         retval = self._commands[command]
 217         if self._command_list is not None:
 218             if not callable(retval):
 219                 raise CommandListError("'%s' not allowed in command list" %
 220                                         command)
 221             self._write_command(command, args)
 222             self._command_list.append(retval)
 223         else:
 224             self._write_command(command, args)
 225             if callable(retval):
 226                 return retval()
 227             return retval
 228
 229     def _write_line(self, line):
 230         self._wfile.write("%s\n" % line)
 231         self._wfile.flush()
 232
 233     def _write_command(self, command, args=[]):
 234         parts = [command]
 235         for arg in args:
 236             parts.append('"%s"' % escape(str(arg)))
 237         self._write_line(" ".join(parts))
 238
 239     def _read_line(self):
 240         line = self._rfile.readline()
 241         if not line.endswith("\n"):
 242             self.disconnect()
 243             raise ConnectionError("Connection lost while reading line")
 244         line = line.rstrip("\n")
 245         if line.startswith(ERROR_PREFIX):
 246             error = line[len(ERROR_PREFIX):].strip()
 247             raise CommandError(error)
 248         if self._command_list is not None:
 249             if line == NEXT:
 250                 return
 251             if line == SUCCESS:
 252                 raise ProtocolError("Got unexpected '%s'" % SUCCESS)
 253         elif line == SUCCESS:
 254             return
 255         return line
 256
 257     def _read_pair(self, separator):
 258         line = self._read_line()
 259         if line is None:
 260             return
 261         pair = line.split(separator, 1)
 262         if len(pair) < 2:
 263             raise ProtocolError("Could not parse pair: '%s'" % line)
 264         return pair
 265
 266     def _read_pairs(self, separator=": "):
 267         pair = self._read_pair(separator)
 268         while pair:
 269             yield pair
 270             pair = self._read_pair(separator)
 271
 272     def _read_list(self):
 273         seen = None
 274         for key, value in self._read_pairs():
 275             if key != seen:
 276                 if seen is not None:
 277                     raise ProtocolError("Expected key '%s', got '%s'" %
 278                                         (seen, key))
 279                 seen = key
 280             yield value
 281
 282     def _read_playlist(self):
 283         for key, value in self._read_pairs(":"):
 284             yield value
 285
 286     def _read_objects(self, delimiters=[]):
 287         obj = {}
 288         for key, value in self._read_pairs():
 289             key = key.lower()
 290             if obj:
 291                 if key in delimiters:
 292                     yield obj
 293                     obj = {}
 294                 elif key in obj:
 295                     if not isinstance(obj[key], list):
 296                         obj[key] = [obj[key], value]
 297                     else:
 298                         obj[key].append(value)
 299                     continue
 300             obj[key] = value
 301         if obj:
 302             yield obj
 303
 304     def _read_command_list(self):
 305         try:
 306             for retval in self._command_list:
 307                 yield retval()
 308         finally:
 309             self._command_list = None
 310         self._fetch_nothing()
 311
 312     def _iterator_wrapper(self, iterator):
 313         try:
 314             for item in iterator:
 315                 yield item
 316         finally:
 317             self._iterating = False
 318
 319     def _wrap_iterator(self, iterator):
 320         if not self.iterate:
 321             return list(iterator)
 322         self._iterating = True
 323         return self._iterator_wrapper(iterator)
 324
 325     def _fetch_nothing(self):
 326         line = self._read_line()
 327         if line is not None:
 328             raise ProtocolError("Got unexpected return value: '%s'" % line)
 329
 330     def _fetch_item(self):
 331         pairs = list(self._read_pairs())
 332         if len(pairs) != 1:
 333             return
 334         return pairs[0][1]
 335
 336     def _fetch_list(self):
 337         return self._wrap_iterator(self._read_list())
 338
 339     def _fetch_playlist(self):
 340         return self._wrap_iterator(self._read_playlist())
 341
 342     def _fetch_object(self):
 343         objs = list(self._read_objects())
 344         if not objs:
 345             return {}
 346         return objs[0]
 347
 348     def _fetch_objects(self, delimiters):
 349         return self._wrap_iterator(self._read_objects(delimiters))
 350
 351     def _fetch_changes(self):
 352         return self._fetch_objects(["cpos"])
 353
 354     def _fetch_songs(self):
 355         return self._fetch_objects(["file"])
 356
 357     def _fetch_playlists(self):
 358         return self._fetch_objects(["playlist"])
 359
 360     def _fetch_database(self):
 361         return self._fetch_objects(["file", "directory", "playlist"])
 362
 363     def _fetch_outputs(self):
 364         return self._fetch_objects(["outputid"])
 365
 366     def _fetch_plugins(self):
 367         return self._fetch_objects(["plugin"])
 368
 369     def _fetch_messages(self):
 370         return self._fetch_objects(["channel"])
 371
 372     def _fetch_command_list(self):
 373         return self._wrap_iterator(self._read_command_list())
 374
 375     def _hello(self):
 376         line = self._rfile.readline()
 377         if not line.endswith("\n"):
 378             raise ConnectionError("Connection lost while reading MPD hello")
 379         line = line.rstrip("\n")
 380         if not line.startswith(HELLO_PREFIX):
 381             raise ProtocolError("Got invalid MPD hello: '%s'" % line)
 382         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 383
 384     def _reset(self):
 385         self.mpd_version = None
 386         self._iterating = False
 387         self._pending = []
 388         self._command_list = None
 389         self._sock = None
 390         self._rfile = _NotConnected()
 391         self._wfile = _NotConnected()
 392
 393     def _connect_unix(self, path):
 394         if not hasattr(socket, "AF_UNIX"):
 395             raise ConnectionError("Unix domain sockets not supported "
 396                                   "on this platform")
 397         sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
 398         sock.connect(path)
 399         return sock
 400
 401     def _connect_tcp(self, host, port):
 402         try:
 403             flags = socket.AI_ADDRCONFIG
 404         except AttributeError:
 405             flags = 0
 406         err = None
 407         for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
 408                                       socket.SOCK_STREAM, socket.IPPROTO_TCP,
 409                                       flags):
 410             af, socktype, proto, canonname, sa = res
 411             sock = None
 412             try:
 413                 sock = socket.socket(af, socktype, proto)
 414                 sock.connect(sa)
 415                 return sock
 416             except socket.error as socket_err:
 417                 err = socket_err
 418                 if sock is not None:
 419                     sock.close()
 420         if err is not None:
 421             raise ConnectionError(str(err))
 422         else:
 423             raise ConnectionError("getaddrinfo returns an empty list")
 424
 425     def connect(self, host, port):
 426         if self._sock is not None:
 427             raise ConnectionError("Already connected")
 428         if host.startswith("/"):
 429             self._sock = self._connect_unix(host)
 430         else:
 431             self._sock = self._connect_tcp(host, port)
 432         self._rfile = self._sock.makefile("r", encoding='utf-8')
 433         self._wfile = self._sock.makefile("w", encoding='utf-8')
 434         try:
 435             self._hello()
 436         except:
 437             self.disconnect()
 438             raise
 439
 440     def disconnect(self):
 441         if hasattr(self._rfile, 'close'):
 442             self._rfile.close()
 443         if hasattr(self._wfile, 'close'):
 444             self._wfile.close()
 445         if hasattr(self._sock, 'close'):
 446             self._sock.close()
 447         self._reset()
 448
 449     def fileno(self):
 450         if self._sock is None:
 451             raise ConnectionError("Not connected")
 452         return self._sock.fileno()
 453
 454     def command_list_ok_begin(self):
 455         if self._command_list is not None:
 456             raise CommandListError("Already in command list")
 457         if self._iterating:
 458             raise IteratingError("Cannot begin command list while iterating")
 459         if self._pending:
 460             raise PendingCommandError("Cannot begin command list "
 461                                       "with pending commands")
 462         self._write_command("command_list_ok_begin")
 463         self._command_list = []
 464
 465     def command_list_end(self):
 466         if self._command_list is None:
 467             raise CommandListError("Not in command list")
 468         if self._iterating:
 469             raise IteratingError("Already iterating over a command list")
 470         self._write_command("command_list_end")
 471         return self._fetch_command_list()
 472
 473
 474 def escape(text):
 475     return text.replace("\\", "\\\\").replace('"', '\\"')
 476
 477
 478 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: