mpd.py

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