nephilim/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 import logging
  19 from PyQt4 import QtCore
  20
  21
  22 HELLO_PREFIX = "OK MPD "
  23 ERROR_PREFIX = "ACK "
  24 SUCCESS = "OK"
  25 NEXT = "list_OK"
  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
  44 class _NotConnected(object):
  45     def __getattr__(self, attr):
  46         return self._dummy
  47
  48     def _dummy(*args):
  49         raise ConnectionError("Not connected")
  50
  51 class MPDClient(QtCore.QObject):
  52     # public
  53     logger = None
  54
  55     # SIGNALS
  56     connect_changed = QtCore.pyqtSignal(bool)
  57     def __init__(self):
  58         QtCore.QObject.__init__(self)
  59         self.logger = logging.getLogger('mpclient.mpdsocket')
  60         self._reset()
  61         self._commands = {
  62             # Admin Commands
  63             "disableoutput":    self._getnone,
  64             "enableoutput":     self._getnone,
  65             "kill":             None,
  66             "update":           self._getitem,
  67             # Informational Commands
  68             "status":           self._getobject,
  69             "stats":            self._getobject,
  70             "outputs":          self._getoutputs,
  71             "commands":         self._getlist,
  72             "notcommands":      self._getlist,
  73             "tagtypes":         self._getlist,
  74             "urlhandlers":      self._getlist,
  75             # Database Commands
  76             "find":             self._getsongs,
  77             "findadd":          self._getnone,
  78             "list":             self._getlist,
  79             "listall":          self._getdatabase,
  80             "listallinfo":      self._getdatabase,
  81             "lsinfo":           self._getdatabase,
  82             "search":           self._getsongs,
  83             "count":            self._getobject,
  84             # Playlist Commands
  85             "add":              self._getnone,
  86             "addid":            self._getitem,
  87             "clear":            self._getnone,
  88             "currentsong":      self._getobject,
  89             "delete":           self._getnone,
  90             "deleteid":         self._getnone,
  91             "load":             self._getnone,
  92             "rename":           self._getnone,
  93             "move":             self._getnone,
  94             "moveid":           self._getnone,
  95             "playlist":         self._getplaylist,
  96             "playlistinfo":     self._getsongs,
  97             "playlistid":       self._getsongs,
  98             "plchanges":        self._getsongs,
  99             "plchangesposid":   self._getchanges,
 100             "rm":               self._getnone,
 101             "save":             self._getnone,
 102             "shuffle":          self._getnone,
 103             "swap":             self._getnone,
 104             "swapid":           self._getnone,
 105             "listplaylist":     self._getlist,
 106             "listplaylistinfo": self._getsongs,
 107             "playlistadd":      self._getnone,
 108             "playlistclear":    self._getnone,
 109             "playlistdelete":   self._getnone,
 110             "playlistmove":     self._getnone,
 111             "playlistfind":     self._getsongs,
 112             "playlistsearch":   self._getsongs,
 113             # Playback Commands
 114             "consume":          self._getnone,
 115             "crossfade":        self._getnone,
 116             "next":             self._getnone,
 117             "pause":            self._getnone,
 118             "play":             self._getnone,
 119             "playid":           self._getnone,
 120             "previous":         self._getnone,
 121             "random":           self._getnone,
 122             "repeat":           self._getnone,
 123             "seek":             self._getnone,
 124             "seekid":           self._getnone,
 125             "setvol":           self._getnone,
 126             "single":           self._getnone,
 127             "stop":             self._getnone,
 128             "volume":           self._getnone,
 129             # Miscellaneous Commands
 130             "clearerror":       self._getnone,
 131             "close":            None,
 132             "password":         self._getnone,
 133             "ping":             self._getnone,
 134         }
 135
 136     def __getattr__(self, attr):
 137         try:
 138             retval = self._commands[attr]
 139         except KeyError:
 140             raise AttributeError("'%s' object has no attribute '%s'" %
 141                                  (self.__class__.__name__, attr))
 142         return lambda *args: self._docommand(attr, args, retval)
 143
 144     def _docommand(self, command, args, retval):
 145         if self._commandlist is not None and not callable(retval):
 146             raise CommandListError("%s not allowed in command list" % command)
 147         try:
 148             self._writecommand(command, args)
 149         except socket.error, e:
 150             self.logger.error('Error sending command: %s.'%e)
 151             self.disconnect_mpd()
 152             return None
 153
 154         if self._commandlist is None:
 155             if callable(retval):
 156                 return retval()
 157             return retval
 158         self._commandlist.append(retval)
 159
 160     def _writeline(self, line):
 161         self._wfile.write("%s\n" % line)
 162         self._wfile.flush()
 163
 164     def _writecommand(self, command, args=[]):
 165         parts = [command]
 166         for arg in args:
 167             parts.append('"%s"' % escape(str(arg)))
 168         self._writeline(" ".join(parts))
 169
 170     def _readline(self):
 171         line = self._rfile.readline()
 172         if not line.endswith("\n"):
 173             raise ConnectionError("Connection lost while reading line")
 174         line = line.rstrip("\n")
 175         if line.startswith(ERROR_PREFIX):
 176             error = line[len(ERROR_PREFIX):].strip()
 177             raise CommandError(error)
 178         if self._commandlist is not None:
 179             if line == NEXT:
 180                 return
 181             if line == SUCCESS:
 182                 raise ProtocolError("Got unexpected '%s'" % SUCCESS)
 183         elif line == SUCCESS:
 184             return
 185         return line
 186
 187     def _readitem(self, separator):
 188         line = self._readline()
 189         if line is None:
 190             return
 191         item = line.split(separator, 1)
 192         if len(item) < 2:
 193             raise ProtocolError("Could not parse item: '%s'" % line)
 194         return item
 195
 196     def _readitems(self, separator=": "):
 197         item = self._readitem(separator)
 198         while item:
 199             yield item
 200             item = self._readitem(separator)
 201         raise StopIteration
 202
 203     def _readlist(self):
 204         seen = None
 205         for key, value in self._readitems():
 206             if key != seen:
 207                 if seen is not None:
 208                     raise ProtocolError("Expected key '%s', got '%s'" %
 209                                         (seen, key))
 210                 seen = key
 211             yield value
 212         raise StopIteration
 213
 214     def _readplaylist(self):
 215         for key, value in self._readitems(":"):
 216             yield value
 217         raise StopIteration
 218
 219     def _readobjects(self, delimiters=[]):
 220         obj = {}
 221         for key, value in self._readitems():
 222             key = key.lower()
 223             if obj:
 224                 if key in delimiters:
 225                     yield obj
 226                     obj = {}
 227                 elif obj.has_key(key):
 228                     if not isinstance(obj[key], list):
 229                         obj[key] = [obj[key], value]
 230                     else:
 231                         obj[key].append(value)
 232                     continue
 233             obj[key] = value
 234         if obj:
 235             yield obj
 236         raise StopIteration
 237
 238     def _readcommandlist(self):
 239         for retval in self._commandlist:
 240             yield retval()
 241         self._commandlist = None
 242         self._getnone()
 243         raise StopIteration
 244
 245     def _getnone(self):
 246         line = self._readline()
 247         if line is not None:
 248             raise ProtocolError("Got unexpected return value: '%s'" % line)
 249
 250     def _getitem(self):
 251         items = list(self._readitems())
 252         if len(items) != 1:
 253             return
 254         return items[0][1]
 255
 256     def _getlist(self):
 257         return self._readlist()
 258
 259     def _getplaylist(self):
 260         return self._readplaylist()
 261
 262     def _getobject(self):
 263         objs = list(self._readobjects())
 264         if not objs:
 265             return {}
 266         return objs[0]
 267
 268     def _getobjects(self, delimiters):
 269         return self._readobjects(delimiters)
 270
 271     def _getsongs(self):
 272         return self._getobjects(["file"])
 273
 274     def _getdatabase(self):
 275         return self._getobjects(["file", "directory", "playlist"])
 276
 277     def _getoutputs(self):
 278         return self._getobjects(["outputid"])
 279
 280     def _getchanges(self):
 281         return self._getobjects(["cpos"])
 282
 283     def _getcommandlist(self):
 284         try:
 285             return self._readcommandlist()
 286         except CommandError:
 287             self._commandlist = None
 288             raise
 289
 290     def _reset(self):
 291         self.mpd_version = None
 292         self._commandlist = None
 293         self._sock = None
 294         self._rfile = _NotConnected()
 295         self._wfile = _NotConnected()
 296
 297     def connect_mpd(self, host, port):
 298         if self._sock:
 299             self.logger.error('Already connected.')
 300         msg = "getaddrinfo returns an empty list"
 301         try:
 302             flags = socket.AI_ADDRCONFIG
 303         except AttributeError:
 304             flags = 0
 305         if port == None:    #assume Unix domain socket
 306             try:
 307                 self._sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
 308                 self._sock.connect(host)
 309             except socket.error, e:
 310                 if self._sock:
 311                     self._sock.close()
 312                 self._sock = None
 313                 self.logger.error('Error connecting to MPD: %s.'%e)
 314         else:
 315             for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC,
 316                                           socket.SOCK_STREAM, socket.IPPROTO_TCP,
 317                                           flags):
 318                 af, socktype, proto, canonname, sa = res
 319                 try:
 320                     self._sock = socket.socket(af, socktype, proto)
 321                     self._sock.connect(sa)
 322                 except socket.error, e:
 323                     if self._sock:
 324                         self._sock.close()
 325                     self._sock = None
 326                     self.logger.error('Error connecting to MPD: %s.'%e)
 327                     continue
 328                 break
 329         if not self._sock:
 330             return
 331         self._rfile = self._sock.makefile('rb')
 332         self._wfile = self._sock.makefile('wb')
 333
 334         # read MPD hello
 335         line = self._rfile.readline()
 336         if not line.endswith("\n"):
 337             self.logger.error('Connnection lost while reading MPD hello')
 338             self.disconnect_mpd()
 339             return False
 340         line = line.rstrip("\n")
 341         if not line.startswith(HELLO_PREFIX):
 342             self.logger.error('Got invalid MPD hello: %s' % line)
 343             self.disconnect_mpd()
 344             return
 345         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 346
 347         self.connect_changed.emit(True)
 348
 349     def disconnect_mpd(self):
 350         self._rfile.close()
 351         self._wfile.close()
 352         self._sock.close()
 353         self._reset()
 354         self.connect_changed.emit(False)
 355
 356     def command_list_ok_begin(self):
 357         if self._commandlist is not None:
 358             raise CommandListError("Already in command list")
 359         self._writecommand("command_list_ok_begin")
 360         self._commandlist = []
 361
 362     def command_list_end(self):
 363         if self._commandlist is None:
 364             raise CommandListError("Not in command list")
 365         self._writecommand("command_list_end")
 366         return self._getcommandlist()
 367
 368
 369 def escape(text):
 370     return text.replace("\\", "\\\\").replace('"', '\\"')
 371
 372
 373 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: