mpd.py

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