awesome/widgets/mpc.lua

   1 -- Originally from https://awesomewm.org/recipes/mpc/
   2
   3 local lgi = require "lgi"
   4 local GLib = lgi.GLib
   5 local Gio = lgi.Gio
   6
   7 local mpc = {}
   8
   9 local function parse_password(host)
  10     -- This function is based on mpd_parse_host_password() from libmpdclient
  11     local position = string.find(host, "@")
  12     if not position then
  13         return host
  14     end
  15     return string.sub(host, position + 1), string.sub(host, 1, position - 1)
  16 end
  17
  18 function mpc.new(host, port, password, error_handler, ...)
  19     host = host or os.getenv("MPD_HOST") or "localhost"
  20     port = port or os.getenv("MPD_PORT") or 6600
  21     if not password then
  22         host, password = parse_password(host)
  23     end
  24     local self = setmetatable({
  25         _host = host,
  26         _port = port,
  27         _password = password,
  28         _error_handler = error_handler or function() end,
  29         _connected = false,
  30         _try_reconnect = false,
  31         _idle_commands = { ... }
  32     }, { __index = mpc })
  33     self:_connect()
  34     return self
  35 end
  36
  37 function mpc:_error(err)
  38     self._connected = false
  39     self._error_handler(err)
  40     self._try_reconnect = not self._try_reconnect
  41     if self._try_reconnect then
  42         self:_connect()
  43     end
  44 end
  45
  46 function mpc:_connect()
  47     if self._connected then return end
  48     -- Reset all of our state
  49     self._reply_handlers = {}
  50     self._pending_reply = {}
  51     self._idle_commands_pending = false
  52     self._idle = false
  53     self._connected = true
  54
  55     -- Set up a new connection
  56     local address
  57     if string.sub(self._host, 1, 1) == "/" then
  58         -- It's a unix socket
  59         address = Gio.UnixSocketAddress.new(self._host)
  60     else
  61         -- Do a TCP connection
  62         address = Gio.NetworkAddress.new(self._host, self._port)
  63     end
  64     local client = Gio.SocketClient()
  65     local conn, err = client:connect(address)
  66
  67     if not conn then
  68         self:_error(err)
  69         return false
  70     end
  71
  72     local input, output = conn:get_input_stream(), conn:get_output_stream()
  73     self._conn, self._output, self._input = conn, output, Gio.DataInputStream.new(input)
  74
  75     -- Read the welcome message
  76     self._input:read_line()
  77
  78     if self._password and self._password ~= "" then
  79         self:_send("password " .. self._password)
  80     end
  81
  82     -- Set up the reading loop. This will asynchronously read lines by
  83     -- calling itself.
  84     local do_read
  85     do_read = function()
  86         self._input:read_line_async(GLib.PRIORITY_DEFAULT, nil, function(obj, res)
  87             local line, err = obj:read_line_finish(res)
  88             -- Ugly API. On success we get string, length-of-string
  89             -- and on error we get nil, error. Other versions of lgi
  90             -- behave differently.
  91             if line == nil or tostring(line) == "" then
  92                 err = "Connection closed"
  93             end
  94             if type(err) ~= "number" then
  95                 self._output, self._input = nil, nil
  96                 self:_error(err)
  97             else
  98                 do_read()
  99                 line = tostring(line)
 100                 if line == "OK" or line:match("^ACK ") then
 101                     local success = line == "OK"
 102                     local arg
 103                     if success then
 104                         arg = self._pending_reply
 105                     else
 106                         arg = { line }
 107                     end
 108                     local handler = self._reply_handlers[1]
 109                     table.remove(self._reply_handlers, 1)
 110                     self._pending_reply = {}
 111                     handler(success, arg)
 112                 else
 113                     local _, _, key, value = string.find(line, "([^:]+):%s(.+)")
 114                     if key then
 115                         self._pending_reply[string.lower(key)] = value
 116                     end
 117                 end
 118             end
 119         end)
 120     end
 121     do_read()
 122
 123     -- To synchronize the state on startup, send the idle commands now. As a
 124     -- side effect, this will enable idle state.
 125     self:_send_idle_commands(true)
 126
 127     return self
 128 end
 129
 130 function mpc:_send_idle_commands(skip_stop_idle)
 131     -- We use a ping to unset this to make sure we never get into a busy
 132     -- loop sending idle / unidle commands. Next call to
 133     -- _send_idle_commands() might be ignored!
 134     if self._idle_commands_pending then
 135         return
 136     end
 137     if not skip_stop_idle then
 138         self:_stop_idle()
 139     end
 140
 141     self._idle_commands_pending = true
 142     for i = 1, #self._idle_commands, 2 do
 143         self:_send(self._idle_commands[i], self._idle_commands[i+1])
 144     end
 145     self:_send("ping", function()
 146         self._idle_commands_pending = false
 147     end)
 148     self:_start_idle()
 149 end
 150
 151 function mpc:_start_idle()
 152     if self._idle then
 153         error("Still idle?!")
 154     end
 155     self:_send("idle", function(success, reply)
 156         if reply.changed then
 157             -- idle mode was disabled by mpd
 158             self:_send_idle_commands()
 159         end
 160     end)
 161     self._idle = true
 162 end
 163
 164 function mpc:_stop_idle()
 165     if not self._idle then
 166         error("Not idle?!")
 167     end
 168     self._output:write("noidle\n")
 169     self._idle = false
 170 end
 171
 172 function mpc:_send(command, callback)
 173     if self._idle then
 174         error("Still idle in send()?!")
 175     end
 176     self._output:write(command .. "\n")
 177     table.insert(self._reply_handlers, callback or function() end)
 178 end
 179
 180 function mpc:send(...)
 181     self:_connect()
 182     if not self._connected then
 183         return
 184     end
 185     local args = { ... }
 186     if not self._idle then
 187         error("Something is messed up, we should be idle here...")
 188     end
 189     self:_stop_idle()
 190     for i = 1, #args, 2 do
 191         self:_send(args[i], args[i+1])
 192     end
 193     self:_start_idle()
 194 end
 195
 196 function mpc:toggle_play()
 197     self:send("status", function(success, status)
 198         if status.state == "stop" then
 199             self:send("play")
 200         else
 201             self:send("pause")
 202         end
 203     end)
 204 end
 205
 206 function clamp(x, min, max)
 207     return math.min(math.max(x, min), max)
 208 end
 209
 210 function mpc:change_volume(change)
 211     self:send("status", function(_, status)
 212         new_vol = clamp(tonumber(status.volume) + change, 0, 100)
 213         self:send("setvol " .. new_vol)
 214     end)
 215 end
 216
 217 function mpc:currentsong()
 218     local currentsong
 219     self:send("currentsong", function(err, song)
 220         if err then error(err) end
 221         currentsong = song
 222     end)
 223     return currentsong
 224 end
 225
 226 --[[
 227
 228 -- Example on how to use this (standalone)
 229
 230 local host, port, password = nil, nil, nil
 231 local m = mpc.new(host, port, password, error,
 232     "status", function(success, status) print("status is", status.state) end)
 233
 234 GLib.timeout_add(GLib.PRIORITY_DEFAULT, 1000, function()
 235     -- Test command submission
 236     m:send("status", function(_, s) print(s.state) end,
 237         "currentsong", function(_, s) print(s.title) end)
 238     m:send("status", function(_, s) print(s.state) end)
 239     -- Force a reconnect
 240     GLib.timeout_add(GLib.PRIORITY_DEFAULT, 1000, function()
 241         m._conn:close()
 242     end)
 243 end)
 244
 245 GLib.MainLoop():run()
 246 --]]
 247
 248 return mpc