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 ProtocolError(MPDError):
  30     pass
  31
  32 class CommandError(MPDError):
  33     pass
  34
  35 class CommandListError(MPDError):
  36     pass
  37
  38
  39 class MPDClient(object):
  40     def __init__(self):
  41         self.iterate = False
  42         self._reset()
  43         self._commands = {
  44             # Admin Commands
  45             "disableoutput":    self._getnone,
  46             "enableoutput":     self._getnone,
  47             "kill":             None,
  48             "update":           self._getitem,
  49             # Informational Commands
  50             "status":           self._getobject,
  51             "stats":            self._getobject,
  52             "outputs":          self._getoutputs,
  53             "commands":         self._getlist,
  54             "notcommands":      self._getlist,
  55             "tagtypes":         self._getlist,
  56             "urlhandlers":      self._getlist,
  57             # Database Commands
  58             "find":             self._getsongs,
  59             "list":             self._getlist,
  60             "listall":          self._getdatabase,
  61             "listallinfo":      self._getdatabase,
  62             "lsinfo":           self._getdatabase,
  63             "search":           self._getsongs,
  64             "count":            self._getobject,
  65             # Playlist Commands
  66             "add":              self._getnone,
  67             "addid":            self._getitem,
  68             "clear":            self._getnone,
  69             "currentsong":      self._getobject,
  70             "delete":           self._getnone,
  71             "deleteid":         self._getnone,
  72             "load":             self._getnone,
  73             "rename":           self._getnone,
  74             "move":             self._getnone,
  75             "moveid":           self._getnone,
  76             "playlist":         self._getplaylist,
  77             "playlistinfo":     self._getsongs,
  78             "playlistid":       self._getsongs,
  79             "plchanges":        self._getsongs,
  80             "plchangesposid":   self._getchanges,
  81             "rm":               self._getnone,
  82             "save":             self._getnone,
  83             "shuffle":          self._getnone,
  84             "swap":             self._getnone,
  85             "swapid":           self._getnone,
  86             "listplaylist":     self._getlist,
  87             "listplaylistinfo": self._getsongs,
  88             "playlistadd":      self._getnone,
  89             "playlistclear":    self._getnone,
  90             "playlistdelete":   self._getnone,
  91             "playlistmove":     self._getnone,
  92             "playlistfind":     self._getsongs,
  93             "playlistsearch":   self._getsongs,
  94             # Playback Commands
  95             "crossfade":        self._getnone,
  96             "next":             self._getnone,
  97             "pause":            self._getnone,
  98             "play":             self._getnone,
  99             "playid":           self._getnone,
 100             "previous":         self._getnone,
 101             "random":           self._getnone,
 102             "repeat":           self._getnone,
 103             "seek":             self._getnone,
 104             "seekid":           self._getnone,
 105             "setvol":           self._getnone,
 106             "stop":             self._getnone,
 107             "volume":           self._getnone,
 108             # Miscellaneous Commands
 109             "clearerror":       self._getnone,
 110             "close":            None,
 111             "password":         self._getnone,
 112             "ping":             self._getnone,
 113         }
 114
 115     def __getattr__(self, attr):
 116         try:
 117             retval = self._commands[attr]
 118         except KeyError:
 119             raise AttributeError, "'%s' object has no attribute '%s'" % \
 120                                   (self.__class__.__name__, attr)
 121         return lambda *args: self._docommand(attr, args, retval)
 122
 123     def _docommand(self, command, args, retval):
 124         if self._commandlist is not None and not callable(retval):
 125             raise CommandListError, "%s not allowed in command list" % command
 126         self._writecommand(command, args)
 127         if self._commandlist is None:
 128             if callable(retval):
 129                 return retval()
 130             return retval
 131         self._commandlist.append(retval)
 132
 133     def _writeline(self, line):
 134         self._sockfile.write("%s\n" % line)
 135         self._sockfile.flush()
 136
 137     def _writecommand(self, command, args=[]):
 138         parts = [command]
 139         for arg in args:
 140             parts.append('"%s"' % escape(str(arg)))
 141         self._writeline(" ".join(parts))
 142
 143     def _readline(self):
 144         line = self._sockfile.readline().rstrip("\n")
 145         if line.startswith(ERROR_PREFIX):
 146             error = line[len(ERROR_PREFIX):].strip()
 147             raise CommandError, error
 148         if self._commandlist is not None:
 149             if line == NEXT:
 150                 return
 151             if line == SUCCESS:
 152                 raise ProtocolError, "Got unexpected '%s'" % SUCCESS
 153         elif line == SUCCESS:
 154             return
 155         return line
 156
 157     def _readitem(self, separator):
 158         line = self._readline()
 159         if line is None:
 160             return
 161         item = line.split(separator, 1)
 162         if len(item) < 2:
 163             raise ProtocolError, "Could not parse item: '%s'" % line
 164         return item
 165
 166     def _readitems(self, separator=": "):
 167         item = self._readitem(separator)
 168         while item:
 169             yield item
 170             item = self._readitem(separator)
 171         raise StopIteration
 172
 173     def _readlist(self):
 174         seen = None
 175         for key, value in self._readitems():
 176             if key != seen:
 177                 if seen is not None:
 178                     raise ProtocolError, "Expected key '%s', got '%s'" % \
 179                                          (seen, key)
 180                 seen = key
 181             yield value
 182         raise StopIteration
 183
 184     def _readplaylist(self):
 185         for key, value in self._readitems(":"):
 186             yield value
 187         raise StopIteration
 188
 189     def _readobjects(self, delimiters=[]):
 190         obj = {}
 191         for key, value in self._readitems():
 192             key = key.lower()
 193             if obj:
 194                 if key in delimiters:
 195                     yield obj
 196                     obj = {}
 197                 elif obj.has_key(key):
 198                     if not isinstance(obj[key], list):
 199                         obj[key] = [obj[key], value]
 200                     else:
 201                         obj[key].append(value)
 202                     continue
 203             obj[key] = value
 204         if obj:
 205             yield obj
 206         raise StopIteration
 207
 208     def _readcommandlist(self):
 209         for retval in self._commandlist:
 210             yield retval()
 211         self._commandlist = None
 212         self._getnone()
 213         raise StopIteration
 214
 215     def _wrapiterator(self, iterator):
 216         if not self.iterate:
 217             return list(iterator)
 218         return iterator
 219
 220     def _getnone(self):
 221         line = self._readline()
 222         if line is not None:
 223             raise ProtocolError, "Got unexpected return value: '%s'" % line
 224
 225     def _getitem(self):
 226         items = list(self._readitems())
 227         if len(items) != 1:
 228             raise ProtocolError, "Expected 1 item, got %i" % len(items)
 229         return items[0][1]
 230
 231     def _getlist(self):
 232         return self._wrapiterator(self._readlist())
 233
 234     def _getplaylist(self):
 235         return self._wrapiterator(self._readplaylist())
 236
 237     def _getobject(self):
 238         objs = list(self._readobjects())
 239         if not objs:
 240             return {}
 241         return objs[0]
 242
 243     def _getobjects(self, delimiters):
 244         return self._wrapiterator(self._readobjects(delimiters))
 245
 246     def _getsongs(self):
 247         return self._getobjects(["file"])
 248
 249     def _getdatabase(self):
 250         return self._getobjects(["file", "directory", "playlist"])
 251
 252     def _getoutputs(self):
 253         return self._getobjects(["outputid"])
 254
 255     def _getchanges(self):
 256         return self._getobjects(["cpos"])
 257
 258     def _getcommandlist(self):
 259         return self._wrapiterator(self._readcommandlist())
 260
 261     def _hello(self):
 262         line = self._sockfile.readline().rstrip("\n")
 263         if not line.startswith(HELLO_PREFIX):
 264             raise ProtocolError, "Got invalid MPD hello: '%s'" % line
 265         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 266
 267     def _reset(self):
 268         self.mpd_version = None
 269         self._commandlist = None
 270         self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 271         self._sockfile = self._sock.makefile("rb+")
 272
 273     def connect(self, host, port):
 274         self.disconnect()
 275         self._sock.connect((host, port))
 276         self._hello()
 277
 278     def disconnect(self):
 279         self._sockfile.close()
 280         self._sock.close()
 281         self._reset()
 282
 283     def command_list_ok_begin(self):
 284         if self._commandlist is not None:
 285             raise CommandListError, "Already in command list"
 286         self._writecommand("command_list_ok_begin")
 287         self._commandlist = []
 288
 289     def command_list_end(self):
 290         if self._commandlist is None:
 291             raise CommandListError, "Not in command list"
 292         self._writecommand("command_list_end")
 293         return self._getcommandlist()
 294
 295
 296 def escape(text):
 297     return text.replace("\\", "\\\\").replace('"', '\\"')
 298
 299
 300 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: