mpd.py

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