mpd.py

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