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 trace_mpc = false
   8
   9 local mpc = {}
  10
  11 local function parse_password(host)
  12     -- This function is based on mpd_parse_host_password() from libmpdclient
  13     local position = string.find(host, "@")
  14     if not position then
  15         return host
  16     end
  17     return string.sub(host, position + 1), string.sub(host, 1, position - 1)
  18 end
  19
  20 function mpc.new(host, port, password, error_handler, ...)
  21     host = host or os.getenv("MPD_HOST") or "localhost"
  22     port = port or os.getenv("MPD_PORT") or 6600
  23     if not password then
  24         host, password = parse_password(host)
  25     end
  26     local self = setmetatable({
  27         _host = host,
  28         _port = port,
  29         _password = password,
  30         _error_handler = error_handler or function() end,
  31         _connected = false,
  32         _try_reconnect = false,
  33         _idle_subsystems = { ... }
  34     }, { __index = mpc })
  35     self:connect()
  36     return self
  37 end
  38
  39 function mpc:_write(command)
  40     if trace_mpc then
  41         print("write: " .. command)
  42     end
  43     self._output:write(command .. "\n")
  44 end
  45
  46 function mpc:_error(err)
  47     self._connected = false
  48     self._error_handler(err)
  49     self._try_reconnect = not self._try_reconnect
  50     if self._try_reconnect then
  51         self:_connect()
  52     end
  53 end
  54
  55 function mpc:connect()
  56     if self._connected then return end
  57     -- Reset all of our state
  58     self._reply_handlers = {}
  59     self._pending_reply = {}
  60     self._idle_commands_pending = false
  61     self._idle = false
  62     self._connected = true
  63
  64     -- Set up a new connection
  65     local address
  66     if string.sub(self._host, 1, 1) == "/" then
  67         -- It's a unix socket
  68         address = Gio.UnixSocketAddress.new(self._host)
  69     else
  70         -- Do a TCP connection
  71         address = Gio.NetworkAddress.new(self._host, self._port)
  72     end
  73     local client = Gio.SocketClient()
  74     local conn, err = client:connect(address)
  75
  76     if not conn then
  77         self:_error(err)
  78         return false
  79     end
  80
  81     local input, output = conn:get_input_stream(), conn:get_output_stream()
  82     self._conn, self._output, self._input = conn, output, Gio.DataInputStream.new(input)
  83
  84     -- Read the welcome message
  85     self._input:read_line()
  86
  87     if self._password and self._password ~= "" then
  88         self:_send("password " .. self._password)
  89     end
  90
  91     -- Set up the reading loop. This will asynchronously read lines by
  92     -- calling itself.
  93     local do_read
  94     do_read = function()
  95         self._input:read_line_async(GLib.PRIORITY_DEFAULT, nil, function(obj, res)
  96             local line, err = obj:read_line_finish(res)
  97             -- Ugly API. On success we get string, length-of-string
  98             -- and on error we get nil, error. Other versions of lgi
  99             -- behave differently.
 100             if line == nil or tostring(line) == "" then
 101                 err = "Connection closed"
 102             end
 103             if type(err) ~= "number" then
 104                 self._output, self._input = nil, nil
 105                 self:_error(err)
 106                 return
 107             end
 108
 109             line = tostring(line)
 110             if line == "OK" or line:match("^ACK ") then
 111                 local success = line == "OK"
 112                 local arg
 113                 if success then
 114                     arg = self._pending_reply
 115                 else
 116                     arg = { line }
 117                 end
 118                 local handler = self._reply_handlers[1]
 119                 table.remove(self._reply_handlers, 1)
 120                 self._pending_reply = {}
 121                 handler(success, arg)
 122
 123                 if next(self._reply_handlers) == nil then
 124                     self:_start_idle()
 125                 end
 126             else
 127                 local _, _, key, value = string.find(line, "([^:]+):%s(.+)")
 128                 if key then
 129                     local k = string.lower(key)
 130                     if k == "binary" then
 131                         value = tonumber(value)
 132                         local data = {}
 133                         while value > 0 do
 134                             local b = assert(obj:read_bytes(value))
 135                             table.insert(data, b.data)
 136                             value = value - #b
 137                         end
 138                         local w = obj:read_bytes(1)  -- read newline at end of binary
 139                         self._pending_reply[k] = table.concat(data)
 140                     elseif k == "changed" then
 141                         if not self._pending_reply[k] then
 142                             self._pending_reply[k] = {}
 143                         end
 144
 145                         self._pending_reply[k][value] = true
 146                     else
 147                         self._pending_reply[k] = value
 148                     end
 149                 end
 150             end
 151             do_read()
 152         end)
 153     end
 154     do_read()
 155
 156     -- To synchronize the state on startup, send the idle commands now.
 157     for i = 1, #self._idle_subsystems, 2 do
 158         self._idle_subsystems[i+1](self)
 159     end
 160
 161     return self
 162 end
 163
 164 function mpc:_start_idle()
 165     if self._idle then
 166         error("start_idle but already idle")
 167     end
 168     self:_send("idle", function(success, reply)
 169         self._idle = false
 170         if reply.changed then
 171             -- idle mode was disabled by mpd
 172             for i = 1, #self._idle_subsystems, 2 do
 173                 local subsys = self._idle_subsystems[i]
 174                 if reply.changed[subsys] then
 175                     self._idle_subsystems[i+1](self)
 176                 end
 177             end
 178         end
 179     end)
 180     self._idle = true
 181 end
 182
 183 function mpc:_stop_idle()
 184     if not self._idle then
 185         error("stop_idle but not idle")
 186     end
 187     self:_write("noidle")
 188     self._idle = false
 189 end
 190
 191 function mpc:_send(command, callback)
 192     if self._idle then
 193         error("Still idle in send()?!")
 194     end
 195     self:_write(command)
 196     table.insert(self._reply_handlers, callback or function() end)
 197 end
 198
 199 function mpc:send(...)
 200     self:connect()
 201     if not self._connected then
 202         return
 203     end
 204     if self._idle then
 205         self:_stop_idle()
 206     end
 207     local args = { ... }
 208     for i = 1, #args, 2 do
 209         self:_send(args[i], args[i+1])
 210     end
 211 end
 212
 213 function mpc:toggle_play()
 214     self:send("status", function(success, status)
 215         if status.state == "stop" then
 216             self:send("play")
 217         else
 218             self:send("pause")
 219         end
 220     end)
 221 end
 222
 223 function clamp(x, min, max)
 224     return math.min(math.max(x, min), max)
 225 end
 226
 227 function mpc:change_volume(change)
 228     self:send("status", function(_, status)
 229         new_vol = clamp(tonumber(status.volume) + change, 0, 100)
 230         self:send("setvol " .. new_vol)
 231     end)
 232 end
 233
 234 function mpc:currentsong()
 235     local currentsong
 236     self:send("currentsong", function(err, song)
 237         if err then error(err) end
 238         currentsong = song
 239     end)
 240     return currentsong
 241 end
 242
 243 local function escape(str)
 244     return "\"" .. str .. "\""
 245 end
 246
 247 function mpc:albumart(uri, handler)
 248     local image_table = {}
 249     local get_art_at
 250     get_art_at = function(off)
 251         self:send("albumart " .. escape(uri) .. " " .. tostring(off), function(success, data)
 252             if not success then
 253                 handler(success, data)
 254             end
 255             table.insert(image_table, data.binary)
 256             if data.binary and #data.binary > 0 then
 257                 get_art_at(off + #data.binary)
 258             else
 259                 data.binary = table.concat(image_table)
 260                 handler(success, data)
 261             end
 262         end)
 263     end
 264     get_art_at(0)
 265 end
 266
 267 --[[
 268
 269 -- Example on how to use this (standalone)
 270
 271 local host, port, password = nil, nil, nil
 272 local m = mpc.new(host, port, password, error,
 273     "status", function(success, status) print("status is", status.state) end)
 274
 275 GLib.timeout_add(GLib.PRIORITY_DEFAULT, 1000, function()
 276     -- Test command submission
 277     m:send("status", function(_, s) print(s.state) end,
 278         "currentsong", function(_, s) print(s.title) end)
 279     m:send("status", function(_, s) print(s.state) end)
 280     -- Force a reconnect
 281     GLib.timeout_add(GLib.PRIORITY_DEFAULT, 1000, function()
 282         m._conn:close()
 283     end)
 284 end)
 285
 286 GLib.MainLoop():run()
 287 --]]
 288
 289 return mpc