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