mpd.py

   1 # Copyright (C) 2008  J. Alexander Treuman <jat@spatialrift.net>
   2 #
   3 # This program is free software: you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation, either version 3 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 import socket
  17
  18
  19 HELLO_PREFIX = "OK MPD "
  20 ERROR_PREFIX = "ACK "
  21 SUCCESS = "OK"
  22 NEXT = "list_OK"
  23
  24
  25 class MPDError(Exception):
  26     pass
  27
  28 class ProtocolError(MPDError):
  29     pass
  30
  31 class CommandError(MPDError):
  32     pass
  33
  34 class CommandListError(MPDError):
  35     pass
  36
  37
  38 class MPDClient(object):
  39     def __init__(self):
  40         self.iterate = False
  41         self._reset()
  42         self._commands = {
  43             # Admin Commands
  44             "disableoutput":    self._getnone,
  45             "enableoutput":     self._getnone,
  46             "kill":             None,
  47             "update":           self._getitem,
  48             # Informational Commands
  49             "status":           self._getobject,
  50             "stats":            self._getobject,
  51             "outputs":          self._getoutputs,
  52             "commands":         self._getlist,
  53             "notcommands":      self._getlist,
  54             "tagtypes":         self._getlist,
  55             "urlhandlers":      self._getlist,
  56             # Database Commands
  57             "find":             self._getsongs,
  58             "list":             self._getlist,
  59             "listall":          self._getdatabase,
  60             "listallinfo":      self._getdatabase,
  61             "lsinfo":           self._getdatabase,
  62             "search":           self._getsongs,
  63             "count":            self._getobject,
  64             # Playlist Commands
  65             "add":              self._getnone,
  66             "addid":            self._getitem,
  67             "clear":            self._getnone,
  68             "currentsong":      self._getobject,
  69             "delete":           self._getnone,
  70             "deleteid":         self._getnone,
  71             "load":             self._getnone,
  72             "rename":           self._getnone,
  73             "move":             self._getnone,
  74             "moveid":           self._getnone,
  75             "playlist":         self._getplaylist,
  76             "playlistinfo":     self._getsongs,
  77             "playlistid":       self._getsongs,
  78             "plchanges":        self._getsongs,
  79             "plchangesposid":   self._getchanges,
  80             "rm":               self._getnone,
  81             "save":             self._getnone,
  82             "shuffle":          self._getnone,
  83             "swap":             self._getnone,
  84             "swapid":           self._getnone,
  85             "listplaylist":     self._getlist,
  86             "listplaylistinfo": self._getsongs,
  87             "playlistadd":      self._getnone,
  88             "playlistclear":    self._getnone,
  89             "playlistdelete":   self._getnone,
  90             "playlistmove":     self._getnone,
  91             "playlistfind":     self._getsongs,
  92             "playlistsearch":   self._getsongs,
  93             # Playback Commands
  94             "crossfade":        self._getnone,
  95             "next":             self._getnone,
  96             "pause":            self._getnone,
  97             "play":             self._getnone,
  98             "playid":           self._getnone,
  99             "previous":         self._getnone,
 100             "random":           self._getnone,
 101             "repeat":           self._getnone,
 102             "seek":             self._getnone,
 103             "seekid":           self._getnone,
 104             "setvol":           self._getnone,
 105             "stop":             self._getnone,
 106             "volume":           self._getnone,
 107             # Miscellaneous Commands
 108             "clearerror":       self._getnone,
 109             "close":            None,
 110             "password":         self._getnone,
 111             "ping":             self._getnone,
 112         }
 113
 114     def __getattr__(self, attr):
 115         try:
 116             retval = self._commands[attr]
 117         except KeyError:
 118             raise AttributeError, "'%s' object has no attribute '%s'" % \
 119                                   (self.__class__.__name__, attr)
 120         return lambda *args: self._docommand(attr, args, retval)
 121
 122     def _docommand(self, command, args, retval):
 123         if self._commandlist is not None and not callable(retval):
 124             raise CommandListError, "%s not allowed in command list" % command
 125         self._writecommand(command, args)
 126         if self._commandlist is None:
 127             if callable(retval):
 128                 return retval()
 129             return retval
 130         self._commandlist.append(retval)
 131
 132     def _writeline(self, line):
 133         self._sockfile.write("%s\n" % line)
 134         self._sockfile.flush()
 135
 136     def _writecommand(self, command, args=[]):
 137         parts = [command]
 138         for arg in args:
 139             parts.append('"%s"' % escape(str(arg)))
 140         self._writeline(" ".join(parts))
 141
 142     def _readline(self):
 143         line = self._sockfile.readline().rstrip("\n")
 144         if line.startswith(ERROR_PREFIX):
 145             error = line[len(ERROR_PREFIX):].strip()
 146             raise CommandError, error
 147         if self._commandlist is not None:
 148             if line == NEXT:
 149                 return
 150             if line == SUCCESS:
 151                 raise ProtocolError, "Got unexpected '%s'" % SUCCESS
 152         elif line == SUCCESS:
 153             return
 154         return line
 155
 156     def _readitem(self, separator):
 157         line = self._readline()
 158         if line is None:
 159             return
 160         item = line.split(separator, 1)
 161         if len(item) < 2:
 162             raise ProtocolError, "Could not parse item: '%s'" % line
 163         return item
 164
 165     def _readitems(self, separator=": "):
 166         item = self._readitem(separator)
 167         while item:
 168             yield item
 169             item = self._readitem(separator)
 170         raise StopIteration
 171
 172     def _readlist(self):
 173         seen = None
 174         for key, value in self._readitems():
 175             if key != seen:
 176                 if seen is not None:
 177                     raise ProtocolError, "Expected key '%s', got '%s'" % \
 178                                          (seen, key)
 179                 seen = key
 180             yield value
 181         raise StopIteration
 182
 183     def _readplaylist(self):
 184         for key, value in self._readitems(":"):
 185             yield value
 186         raise StopIteration
 187
 188     def _readobjects(self, delimiters=[]):
 189         obj = {}
 190         for key, value in self._readitems():
 191             key = key.lower()
 192             if obj:
 193                 if key in delimiters:
 194                     yield obj
 195                     obj = {}
 196                 elif obj.has_key(key):
 197                     if not isinstance(obj[key], list):
 198                         obj[key] = [obj[key], value]
 199                     else:
 200                         obj[key].append(value)
 201                     continue
 202             obj[key] = value
 203         if obj:
 204             yield obj
 205         raise StopIteration
 206
 207     def _readcommandlist(self):
 208         for retval in self._commandlist:
 209             yield retval()
 210         self._commandlist = None
 211         self._getnone()
 212         raise StopIteration
 213
 214     def _wrapiterator(self, iterator):
 215         if not self.iterate:
 216             return list(iterator)
 217         return iterator
 218
 219     def _getnone(self):
 220         line = self._readline()
 221         if line is not None:
 222             raise ProtocolError, "Got unexpected return value: '%s'" % line
 223
 224     def _getitem(self):
 225         items = list(self._readitems())
 226         if len(items) != 1:
 227             raise ProtocolError, "Expected 1 item, got %i" % len(items)
 228         return items[0][1]
 229
 230     def _getlist(self):
 231         return self._wrapiterator(self._readlist())
 232
 233     def _getplaylist(self):
 234         return self._wrapiterator(self._readplaylist())
 235
 236     def _getobject(self):
 237         objs = list(self._readobjects())
 238         if not objs:
 239             return {}
 240         return objs[0]
 241
 242     def _getobjects(self, delimiters):
 243         return self._wrapiterator(self._readobjects(delimiters))
 244
 245     def _getsongs(self):
 246         return self._getobjects(["file"])
 247
 248     def _getdatabase(self):
 249         return self._getobjects(["file", "directory", "playlist"])
 250
 251     def _getoutputs(self):
 252         return self._getobjects(["outputid"])
 253
 254     def _getchanges(self):
 255         return self._getobjects(["cpos"])
 256
 257     def _getcommandlist(self):
 258         return self._wrapiterator(self._readcommandlist())
 259
 260     def _hello(self):
 261         line = self._sockfile.readline().rstrip("\n")
 262         if not line.startswith(HELLO_PREFIX):
 263             raise ProtocolError, "Got invalid MPD hello: '%s'" % line
 264         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 265
 266     def _reset(self):
 267         self.mpd_version = None
 268         self._commandlist = None
 269         self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 270         self._sockfile = self._sock.makefile("rb+")
 271
 272     def connect(self, host, port):
 273         self.disconnect()
 274         self._sock.connect((host, port))
 275         self._hello()
 276
 277     def disconnect(self):
 278         self._sockfile.close()
 279         self._sock.close()
 280         self._reset()
 281
 282     def command_list_ok_begin(self):
 283         if self._commandlist is not None:
 284             raise CommandListError, "Already in command list"
 285         self._writecommand("command_list_ok_begin")
 286         self._commandlist = []
 287
 288     def command_list_end(self):
 289         if self._commandlist is None:
 290             raise CommandListError, "Not in command list"
 291         self._writecommand("command_list_end")
 292         return self._getcommandlist()
 293
 294
 295 def escape(text):
 296     return text.replace("\\", "\\\\").replace('"', '\\"')
 297
 298
 299 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: