mpd.py

   1 #! /usr/bin/env python
   2
   3 # TODO: check for EOF when reading and benchmark it
   4 # TODO: converter support
   5 # TODO: global for parsing MPD_HOST/MPD_PORT
   6 # TODO: global for parsing MPD error messages
   7 # TODO: IPv6 support (AF_INET6)
   8
   9 import socket
  10
  11
  12 HELLO_PREFIX = "OK MPD "
  13 ERROR_PREFIX = "ACK "
  14 SUCCESS = "OK"
  15 NEXT = "list_OK"
  16
  17
  18 class MPDError(Exception):
  19     pass
  20
  21 class ProtocolError(MPDError):
  22     pass
  23
  24 class CommandError(MPDError):
  25     pass
  26
  27 class CommandListError(MPDError):
  28     pass
  29
  30
  31 class MPDClient(object):
  32     def __init__(self):
  33         self.iterate = False
  34         self._reset()
  35         self._commands = {
  36             # Admin Commands
  37             "disableoutput":    self._getnone,
  38             "enableoutput":     self._getnone,
  39             "kill":             None,
  40             "update":           self._getitem,
  41             # Informational Commands
  42             "status":           self._getobject,
  43             "stats":            self._getobject,
  44             "outputs":          self._getoutputs,
  45             "commands":         self._getlist,
  46             "notcommands":      self._getlist,
  47             "tagtypes":         self._getlist,
  48             "urlhandlers":      self._getlist,
  49             # Database Commands
  50             "find":             self._getsongs,
  51             "list":             self._getlist,
  52             "listall":          self._getdatabase,
  53             "listallinfo":      self._getdatabase,
  54             "lsinfo":           self._getdatabase,
  55             "search":           self._getsongs,
  56             "count":            self._getobject,
  57             # Playlist Commands
  58             "add":              self._getnone,
  59             "addid":            self._getitem,
  60             "clear":            self._getnone,
  61             "currentsong":      self._getobject,
  62             "delete":           self._getnone,
  63             "deleteid":         self._getnone,
  64             "load":             self._getnone,
  65             "rename":           self._getnone,
  66             "move":             self._getnone,
  67             "moveid":           self._getnone,
  68             "playlist":         self._getplaylist,
  69             "playlistinfo":     self._getsongs,
  70             "playlistid":       self._getsongs,
  71             "plchanges":        self._getsongs,
  72             "plchangesposid":   self._getchanges,
  73             "rm":               self._getnone,
  74             "save":             self._getnone,
  75             "shuffle":          self._getnone,
  76             "swap":             self._getnone,
  77             "swapid":           self._getnone,
  78             "listplaylist":     self._getlist,
  79             "listplaylistinfo": self._getsongs,
  80             "playlistadd":      self._getnone,
  81             "playlistclear":    self._getnone,
  82             "playlistdelete":   self._getnone,
  83             "playlistmove":     self._getnone,
  84             "playlistfind":     self._getsongs,
  85             "playlistsearch":   self._getsongs,
  86             # Playback Commands
  87             "crossfade":        self._getnone,
  88             "next":             self._getnone,
  89             "pause":            self._getnone,
  90             "play":             self._getnone,
  91             "playid":           self._getnone,
  92             "previous":         self._getnone,
  93             "random":           self._getnone,
  94             "repeat":           self._getnone,
  95             "seek":             self._getnone,
  96             "seekid":           self._getnone,
  97             "setvol":           self._getnone,
  98             "stop":             self._getnone,
  99             "volume":           self._getnone,
 100             # Miscellaneous Commands
 101             "clearerror":       self._getnone,
 102             "close":            None,
 103             "password":         self._getnone,
 104             "ping":             self._getnone,
 105         }
 106
 107     def __getattr__(self, attr):
 108         try:
 109             retval = self._commands[attr]
 110         except KeyError:
 111             raise AttributeError, "'%s' object has no attribute '%s'" % \
 112                                   (self.__class__.__name__, attr)
 113         return lambda *args: self._docommand(attr, args, retval)
 114
 115     def _docommand(self, command, args, retval):
 116         if self._commandlist is not None and not callable(retval):
 117             raise CommandListError, "%s not allowed in command list" % command
 118         self._writecommand(command, args)
 119         if self._commandlist is None:
 120             if callable(retval):
 121                 return retval()
 122             return retval
 123         self._commandlist.append(retval)
 124
 125     def _writeline(self, line):
 126         self._sockfile.write("%s\n" % line)
 127         self._sockfile.flush()
 128
 129     def _writecommand(self, command, args=[]):
 130         parts = [command]
 131         for arg in args:
 132             parts.append('"%s"' % escape(str(arg)))
 133         self._writeline(" ".join(parts))
 134
 135     def _readline(self):
 136         line = self._sockfile.readline().rstrip("\n")
 137         if line.startswith(ERROR_PREFIX):
 138             error = line[len(ERROR_PREFIX):].strip()
 139             raise CommandError, error
 140         if self._commandlist is not None:
 141             if line == NEXT:
 142                 return
 143             if line == SUCCESS:
 144                 raise ProtocolError, "Got unexpected '%s'" % SUCCESS
 145         elif line == SUCCESS:
 146             return
 147         return line
 148
 149     def _readitem(self, separator):
 150         line = self._readline()
 151         if line is None:
 152             return
 153         item = line.split(separator, 1)
 154         if len(item) < 2:
 155             raise ProtocolError, "Could not parse item: '%s'" % line
 156         return item
 157
 158     def _readitems(self, separator=": "):
 159         item = self._readitem(separator)
 160         while item:
 161             yield item
 162             item = self._readitem(separator)
 163         raise StopIteration
 164
 165     def _readlist(self):
 166         seen = None
 167         for key, value in self._readitems():
 168             if key != seen:
 169                 if seen is not None:
 170                     raise ProtocolError, "Expected key '%s', got '%s'" % \
 171                                          (seen, key)
 172                 seen = key
 173             yield value
 174         raise StopIteration
 175
 176     def _readplaylist(self):
 177         for key, value in self._readitems(":"):
 178             yield value
 179         raise StopIteration
 180
 181     def _readobjects(self, delimiters=[]):
 182         obj = {}
 183         for key, value in self._readitems():
 184             key = key.lower()
 185             if obj:
 186                 if key in delimiters:
 187                     yield obj
 188                     obj = {}
 189                 elif obj.has_key(key):
 190                     if not isinstance(obj[key], list):
 191                         obj[key] = [obj[key], value]
 192                     else:
 193                         obj[key].append(value)
 194                     continue
 195             obj[key] = value
 196         if obj:
 197             yield obj
 198         raise StopIteration
 199
 200     def _readcommandlist(self):
 201         for retval in self._commandlist:
 202             yield retval()
 203         self._commandlist = None
 204         self._getnone()
 205         raise StopIteration
 206
 207     def _wrapiterator(self, iterator):
 208         if not self.iterate:
 209             return list(iterator)
 210         return iterator
 211
 212     def _getnone(self):
 213         line = self._readline()
 214         if line is not None:
 215             raise ProtocolError, "Got unexpected return value: '%s'" % line
 216
 217     def _getitem(self):
 218         items = list(self._readitems())
 219         if len(items) != 1:
 220             raise ProtocolError, "Expected 1 item, got %i" % len(items)
 221         return items[0][1]
 222
 223     def _getlist(self):
 224         return self._wrapiterator(self._readlist())
 225
 226     def _getplaylist(self):
 227         return self._wrapiterator(self._readplaylist())
 228
 229     def _getobject(self):
 230         objs = list(self._readobjects())
 231         if not objs:
 232             return {}
 233         return objs[0]
 234
 235     def _getobjects(self, delimiters):
 236         return self._wrapiterator(self._readobjects(delimiters))
 237
 238     def _getsongs(self):
 239         return self._getobjects(["file"])
 240
 241     def _getdatabase(self):
 242         return self._getobjects(["file", "directory", "playlist"])
 243
 244     def _getoutputs(self):
 245         return self._getobjects(["outputid"])
 246
 247     def _getchanges(self):
 248         return self._getobjects(["cpos"])
 249
 250     def _getcommandlist(self):
 251         return self._wrapiterator(self._readcommandlist())
 252
 253     def _hello(self):
 254         line = self._sockfile.readline().rstrip("\n")
 255         if not line.startswith(HELLO_PREFIX):
 256             raise ProtocolError, "Got invalid MPD hello: '%s'" % line
 257         self.mpd_version = line[len(HELLO_PREFIX):].strip()
 258
 259     def _reset(self):
 260         self.mpd_version = None
 261         self._commandlist = None
 262         self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 263         self._sockfile = self._sock.makefile("rb+")
 264
 265     def connect(self, host, port):
 266         self.disconnect()
 267         self._sock.connect((host, port))
 268         self._hello()
 269
 270     def disconnect(self):
 271         self._sockfile.close()
 272         self._sock.close()
 273         self._reset()
 274
 275     def command_list_ok_begin(self):
 276         if self._commandlist is not None:
 277             raise CommandListError, "Already in command list"
 278         self._writecommand("command_list_ok_begin")
 279         self._commandlist = []
 280
 281     def command_list_end(self):
 282         if self._commandlist is None:
 283             raise CommandListError, "Not in command list"
 284         self._writecommand("command_list_end")
 285         return self._getcommandlist()
 286
 287
 288 def escape(text):
 289     return text.replace("\\", "\\\\").replace('"', '\\"')
 290
 291
 292 # vim: set expandtab shiftwidth=4 softtabstop=4 textwidth=79: