mpd.py

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