nowplaying.lua

-- CONFIGDIR=http://www.videolan.org/support/faq.html#Config
-- Save to: $CONFIGDIR/lua/extensions/nowplaying.lua

require "io"
require "string"

function descriptor()
   return {
      title = "Now playing",
      version = "2.0",
      author = "Richard Andrew Cattermole",
      url = 'https://gist.github.com/rikkimax/39b46f7ff3aa0c93b5cf',
      shortdesc = "Saves to file the currently playing song",
      description = "Saves the currently playing song name and artist to ~/now_playing.txt",
      capabilities = {"input-listener", "meta-listener", "playing-listener"}
   }
end

function activate()
   -- this is where extension starts
   -- for example activation of extension opens custom dialog box:
   vlc.msg.dbg("[Now Playing] Activating")
   handleItem()
end
function deactivate()
   -- what should be done on deactivation of extension
   vlc.msg.dbg("[Now Playing] Deactivating")
   handleItem()
end

function input_changed()
    -- related to capabilities={"input-listener"} in descriptor()
    -- triggered by Start/Stop media input event
    handleItem() 
end
function playing_changed()
    -- related to capabilities={"playing-listener"} in descriptor()
    -- triggered by Pause/Play madia input event
    handleItem() 
end
function meta_changed()
   -- related to capabilities={"meta-listener"} in descriptor()
   -- triggered by available media input meta data?
   handleItem()
end

function handleItem()
    item = (vlc.player and vlc.player.item()) or vlc.item or vlc.input.item()
    
    -- handle Windows and posix.
    -- on Windows vlc.config.homedir returns Documents directory not the /actual/ home directory
    local homeDir = os.getenv("USERPROFILE") or vlc.config.homedir()
    local theFile = homeDir .. "/now_playing.txt"
    
    vlc.msg.dbg("[Now Playing] " .. theFile)
    file=io.open(theFile, "w+")

    if not (item == nil) and ((vlc.player and vlc.player.is_playing()) or vlc.input.is_playing()) then  
        metas=item:metas()
        artist=trim(metas.artist)
        title=trim(metas.title)
    
        local text=title .. " - " .. artist
        vlc.msg.dbg("[Now Playing] " .. text)
        file:write(text)
    else
        vlc.msg.dbg("[Now Playing] no input item playing")
        file:write("No song currently playing")
    end
    
    file:close()
end

function trim(s)
  local _,i1 = string.find(s,'^%s*')
  local i2 = string.find(s,'%s*$')
  return string.sub(s,i1+1,i2-1)
end