mpd.py

   1 # Python MPD client library
   2 # Copyright (C) 2008  J. Alexander Treuman <jat@spatialrift.net>
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU 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 # This program 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 General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program.  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
  42 class _NotConnected(object):
  43     def __getattr__(self, attr):
  44         return self._dummy
  45
  46     def _dummy(*args):
  47         raise ConnectionError("Not connected")
  48
  49 class MPDClient(object):
  50     def __init__(self):
  51         self.iterate = False
  52         self._reset()
  53         self._commands = {
  54             # Status Commands
  55             "clearerror":       self._getnone,
  56             "currentsong":      self._getobject,
  57             "idle":             self._getlist,
  58             "noidle":           None,
  59             "status":           self._getobject,
  60             "stats":            self._getobject,
  61             # Playback Option Commands
  62             "crossfade":        self._getnone,
  63             "random":           self._getnone,
  64             "repeat":           self._getnone,
  65             "setvol":           self._getnone,
  66             "volume":           self._getnone,
  67             # Playback Control Commands
  68             "next":             self._getnone,
  69             "pause":            self._getnone,
  70             "play":             self._getnone,
  71             "playid":           self._getnone,
  72             "previous":         self._getnone,
  73             "seek":             self._getnone,
  74             "seekid":           self._getnone,
  75             "stop":             self._getnone,
  76             # Playlist Commands
  77             "add":              self._getnone,
  78             "addid":            self._getitem,
  79             "clear":            self._getnone,
  80             "delete":           self._getnone,
  81             "deleteid":         self._getnone,
  82             "move":             self._getnone,
  83             "moveid":           self._getnone,
  84             "playlist":         self._getplaylist,
  85             "playlistfind":     self._getsongs,
  86             "playlistid":       self._getsongs,
  87             "playlistinfo":     self._getsongs,
  88             "playlistsearch":   self._getsongs,
  89             "plchanges":        self._getsongs,
  90             "plchangesposid":   self._getchanges,
  91             "shuffle":          self._getnone,
  92             "swap":             self._getnone,
  93             "swapid":           self._getnone,
  94             # Stored Playlist Commands
  95             "listplaylist":     self._getlist,
  96             "listplaylistinfo": self._getsongs,
  97             "listplaylists":    self._getplaylists,
  98             "load":             self._getnone,
  99             "playlistadd":      self._getnone,
 100             "playlistclear":    self._getnone,
 101             "playlistdelete":   self._getnone,
 102             "playlistmove":     self._getnone,
 103             "rename":           self._getnone,
 104             "rm":               self._getnone,
 105             "save":             self._getnone,
 106             # Database Commands
 107             "count":            self._getobject,
 108             "find":             self._getsongs,
 109             "list":             self._getlist,
 110             "listall":          self._getdatabase,
 111             "listallinfo":      self._getdatabase,
 112             "lsinfo":           self._getdatabase,
 113             "search":           self._getsongs,
 114             "update":           self._getitem,
 115             # Connection Commands
 116             "close":            None,
 117             "kill":             None,
 118             "password":         self._getnone,
 119             "ping":             self._getnone,
 120             # Audio Output Commands
 121             "disableoutput":    self._getnone,
 122             "enableoutput":     self._getnone,
 123             "outputs":          self._getoutputs,
 124             # Reflection Commands
 125             "commands":         self._getlist,
 126             "notcommands":      self._getlist,
 127             "tagtypes":         self._getlist,
 128             "urlhandlers":      self._getlist,
 129         }
 130
 131     def __getattr__(self, attr):
 132         try:
 133             retval = self._commands[attr]
 134         except KeyError:
 135             raise AttributeError("'%s' object has no attribute '%s'" %
 136                                  (self.__class__.__name__, attr))
 137         return lambda *args: self._docommand(attr, args, retval)
 138
 139     def _docommand(self, command, args, retval):
 140         if self._commandlist is not None and not callable(retval):
 141             raise CommandListError("%s not allowed in command list" % command)
 142         self._writecommand(command, args)
 143         if self._commandlist is None:
 144             if callable(retval):
 145                 return retval()
 146             return retval
 147         self._commandlist.append(retval)
 148
 149     def _writeline(self, line):
 150         self._wfile.write("%s\n" % line)
 151         self._wfile.flush()
 152
 153     def _writecommand(self, command, args=[]):
 154         parts = [command]
 155         for arg in args:
 156             parts.append('"%s"' % escape(str(arg)))
 157         self._writeline(" ".join(parts))
 158
 159     def _readline(self):
 160         line = self._rfile.readline()
 161         if not line.endswith("\n"):
 162             raise ConnectionError("Connection lost while reading line")
 163         line = line.rstrip("\n")
 164         if line.startswith(ERROR_PREFIX):
 165             error = line[len(ERROR_PREFIX):].strip()
 166             raise CommandError(error)
 167         if self._commandlist is not None:
 168             if line == NEXT:
 169                 return
 170             if line == SUCCESS:
 171                 raise ProtocolError("Got unexpected '%s'" % SUCCESS)
 172         elif line == SUCCESS:
 173             return
 174         return line
 175
 176     def _readitem(self, separator):
 177         line = self._readline()
 178         if line is None:
 179             return
 180         item = line.split(separator, 1)
 181         if len(item) < 2:
 182             raise ProtocolError("Could not parse item: '%s'" % line)
 183         return item
 184
 185     def _readitems(self, separator=": "):
 186         item = self._readitem(separator)
 187         while item:
 188             yield item
 189             item = self._readitem(separator)
 190         raise StopIteration
 191
 192     def _readlist(self):
 193         seen = None
 194         for key, value in self._readitems():
 195             if key != seen:
 196                 if seen is not None:
 197                     raise ProtocolError("Expected key '%s', got '%s'" %
 198                                         (seen, key))
 199                 seen = key
 200             yield value
 201         raise StopIteration
 202
 203     def _readplaylist(self):
 204         for key, value in self._readitems(":"):
 205             yield value
 206         raise StopIteration
 207
 208     def _readobjects(self, delimiters=[]):
 209         obj = {}
 210         for key, value in self._readitems():
 211             key = key.lower()
 212             if obj:
 213                 if key in delimiters:
 214                     yield obj
 215                     obj = {}
 216                 elif obj.has_key(key):
 217                     if not isinstance(obj[key], list):
 218                         obj[key] = [obj[key], value]
 219                     else:
 220                         obj[key].append(value)
 221                     continue
 222             obj[key] = value
 223         if obj:
 224             yield obj
 225         raise StopIteration
 226
 227     def _readcommandlist(self):
 228         for retval in self._commandlist:
 229             yield retval()
 230         self._commandlist = None
 231         self._getnone()
 232         raise StopIteration
 233
 234     def _wrapiterator(self, iterator):
 235         if not self.iterate:
 236             return list(iterator)
 237         return iterator
 238
 239     def _getnone(self):
 240         line = self._readline()
 241         if line is not None:
 242             raise ProtocolError("Got unexpected return value: '%s'" % line)
 243
 244     def _getitem(self):
 245         items = list(self._readitems())
 246         if len(items) != 1:
 247             return
 248         return items[0][1]
 249
 250     def _getlist(self):
 251         return self._wrapiterator(self._readlist())
 252
 253     def _getplaylist(self):
 254         return self._wrapiterator(self._readplaylist())
 255
 256     def _getobject(self):
 257         objs = list(self._readobjects())
 258         if not objs:
 259             return {}
 260         return objs[0]
 261
 262     def _getobjects(self, delimiters):
 263         return self._wrapiterator(self._readobjects(delimiters))
 264
 265     def _getsongs(self):
 266         return self._getobjects(["file"])
 267
 268     def _getplaylists(self):
 269         return self._getobjects(["playlist"])
 270
 271     def _getdatabase(self):
 272         return self._getobjects(["file", "directory", "playlist"])
 273
 274     def _getoutputs(self):
 275         return self._getobjects(["outputid"])
 276
 277     def _getchanges(self):
 278         return self._getobjects(["cpos"])
 279
 280     def _getcommandlist(self):
 281         return self._wrapiterator(self._readcommandlist())
 282
 283     def _hello(self):
 284         line = self._rfile.readline()
 285         if not line.endswith("\n"):
 286             raise ConnectionError("Connection lost while reading MPD hello")
 287         line = line.rstrip("\n")
 288         if not line.startswith(HELLO_PREFIX):
 289             raise ProtocolError("Got invalid MPD hello: '%s'" % line)
 290         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 291
 292     def _reset(self):
 293         self.mpd_version = None
 294         self._commandlist = None
 295         self._sock = None
 296         self._rfile = _NotConnected()
 297         self._wfile = _NotConnected()
 298
 299     def connect(self, host, port):
 300         if self._sock:
 301             raise ConnectionError("Already connected")
 302         msg = "getaddrinfo returns an empty list"
 303         try:
 304             flags = socket.AI_ADDRCONFIG
 305         except AttributeError:
 306             flags = 0
 307         for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
 308                                       socket.SOCK_STREAM, socket.IPPROTO_TCP,
 309                                       flags):
 310             af, socktype, proto, canonname, sa = res
 311             try:
 312                 self._sock = socket.socket(af, socktype, proto)
 313                 self._sock.connect(sa)
 314             except socket.error, msg:
 315                 if self._sock:
 316                     self._sock.close()
 317                 self._sock = None
 318                 continue
 319             break
 320         if not self._sock:
 321             raise socket.error(msg)
 322         self._rfile = self._sock.makefile("rb")
 323         self._wfile = self._sock.makefile("wb")
 324         try:
 325             self._hello()
 326         except:
 327             self.disconnect()
 328             raise
 329
 330     def disconnect(self):
 331         self._rfile.close()
 332         self._wfile.close()
 333         self._sock.close()
 334         self._reset()
 335
 336     def command_list_ok_begin(self):
 337         if self._commandlist is not None:
 338             raise CommandListError("Already in command list")
 339         self._writecommand("command_list_ok_begin")
 340         self._commandlist = []
 341
 342     def command_list_end(self):
 343         if self._commandlist is None:
 344             raise CommandListError("Not in command list")
 345         self._writecommand("command_list_end")
 346         return self._getcommandlist()
 347
 348
 349 def escape(text):
 350     return text.replace("\\", "\\\\").replace('"', '\\"')
 351
 352
 353 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: