mpd.py

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