lib/mpd.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2013 Alexis Laferrière <alexis.laf@xymus.net>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 # Client for a MPD server
  18 module mpd
  19
  20 import socket
  21
  22 # Connection to a MPD server
  23 class MPDConnection
  24         var socket: nullable Socket = null
  25
  26         var host: String
  27         var port: Int
  28         var password: nullable String
  29
  30         var error: nullable String = null
  31
  32         # Connect to the MPD server
  33         fun connect
  34         do
  35                 var p: nullable Socket = null
  36
  37                 p = new Socket.stream_with_host(host, port)
  38                 p.connect
  39
  40                 sys.nanosleep(0,5000)
  41
  42                 var rep = p.read
  43                 assert not rep.is_empty
  44                 if not rep.has_prefix("OK") then
  45                         print "MPD responded {rep}"
  46                         abort
  47                 end
  48
  49                 socket = p
  50
  51                 var password = password
  52                 if password != null then
  53                         write_and_check("password {password}\n")
  54                 end
  55         end
  56
  57         # Write a command to the MPD server
  58         protected fun write_and_check(msg: String)
  59         do
  60                 if socket == null then connect
  61
  62                 socket.write(msg)
  63                 sys.nanosleep(0,5000)
  64                 var rep = socket.read
  65                 if not rep.has_prefix("OK") then
  66                         print "Error: MPD responded {rep}"
  67                         socket.close
  68                         socket = null
  69                 end
  70         end
  71
  72         # Get MPD server status
  73         fun status: nullable ServerStatus
  74         do
  75                 if socket == null then connect
  76
  77                 var volume: nullable Int = null
  78                 var state: nullable String = null
  79
  80                 # get current status
  81                 socket.write("status\n")
  82                 var rep = socket.read
  83                 for l in rep.split_with("\n") do
  84                         var words = l.split_with(" ")
  85                         if words.length > 1 then
  86                                 var key = words[0].to_lower
  87                                 var first_space = l.index_of(' ')
  88                                 var rest = l.substring_from(first_space+1)
  89                                 if  key == "volume:" then
  90                                         volume = rest.to_i
  91                                         if volume == -1 then volume = null
  92                                 else if  key == "volume:" then
  93                                         state = rest
  94                                 end
  95                         end
  96                 end
  97
  98                 if state != null then
  99                         return new ServerStatus(volume, state)
 100                 else
 101                         return null
 102                 end
 103         end
 104
 105         # Set the volume relatively
 106         fun relative_volume=(diff: Int)
 107         do
 108                 if socket == null then connect
 109
 110                 var status = status
 111                 if status != null then
 112                         var vol = status.volume
 113                         if vol != null then
 114                                 var new_vol = vol + diff
 115                                 new_vol = new_vol.max(0).min(100)
 116                                 volume = new_vol
 117                                 return
 118                         end
 119                 end
 120
 121                 error = "Cannot get volume"
 122         end
 123
 124         fun volume=(vol: Int) do write_and_check("setvol {vol}\n")
 125
 126         # Pause music playing on the MPD server
 127         fun pause do write_and_check("pause\n")
 128
 129         # Stop music playing on the MPD server
 130         fun stop do write_and_check("stop\n")
 131
 132         # Play music playing on the MPD server
 133         fun play do write_and_check("play\n")
 134
 135         # Get information on the currently playing song on the MPD server
 136         fun current_song: nullable SongInfo
 137         do
 138                 if socket == null then connect
 139
 140                 var album: nullable String = null
 141                 var artist: nullable String = null
 142                 var title: nullable String = null
 143
 144                 socket.write("currentsong\n")
 145                 var rep = socket.read
 146                 for l in rep.split_with("\n") do
 147                         var words = l.split_with(" ")
 148                         if words.length > 1 then
 149                                 var key = words[0].to_lower
 150                                 var first_space = l.index_of(' ')
 151                                 var rest = l.substring_from(first_space+1)
 152                                 if key == "album:" then
 153                                         album = rest
 154                                 else if key == "artist:" then
 155                                         artist = rest
 156                                 else if key == "title:" then
 157                                         title = rest
 158                                 end
 159                         end
 160                 end
 161
 162                 if album != null and artist != null and title != null then
 163                         return new SongInfo(album, artist, title)
 164                 else
 165                         return null
 166                 end
 167         end
 168 end
 169
 170 # MPD song info
 171 class SongInfo
 172         var album: String
 173         var artist: String
 174         var title: String
 175 end
 176
 177 # MPD server status
 178 class ServerStatus
 179         var volume: nullable Int
 180         var state: String
 181 end