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