title: Use metadata in filename when saving harbor input Liquidsoap
body: <p>So I have an instance of Liquidsoap, which I am using to stream to an Icecast server.</p>
  
  <p>I'd like to record any live broadcasts that take place automatically, which I am now doing and is working well.</p>
  
  <p>What I'd like to do is use the metadata (specifically the songname) of the live show when creating the mp3 archive.</p>
  
  <pre><code>                #!/usr/local/bin/liquidsoap
  
              set("log.file",true)
              set("log.file.path","/var/log/liquidsoap/radiostation.log")
              set("log.stdout",true)
              set("log.level",3)
              #-------------------------------------
  
              set("harbor.bind_addr","0.0.0.0")
  
              #-------------------------------------
  
              backup_playlist = playlist("/home/radio/playlists/playlist.pls",conservative=true,reload_mode="watch")
              output.dummy(fallible=true,backup_playlist)
  
              #-------------------------------------
  
              live_dj = input.harbor(id="live",port=9000,password="XXX", "live")
  
              date = '%m-%d-%Y'
              time = '%H:%M:%S'
              output.file(%mp3, "/var/www/recorded-shows/#{Title} - Recorded On #{date} At #{time}.mp3", live_dj, fallible=true)
  
              #time_stamp = '%m-%d-%Y, %H:%M:%S'
              #output.file(%mp3, "/var/www/recorded-shows/live_dj_#{time_stamp}.mp3", live_dj, fallible=true)
  
              #-------------------------------------
  
              on_fail = single("/home/radio/fallback/Enei -The Moment Feat DRS.mp3")
  
              #-------------------------------------
  
              source = fallback(track_sensitive=false,
                                [live_dj, backup_playlist, on_fail])
  
              # We output the stream to icecast
              output.icecast(%mp3,id="icecast",
                             mount="myradio.mp3",
                             host="localhost", password="XXX",
                             icy_metadata="true",description="cool radio",
                             url="http://myradio.fm",
                             source)
  </code></pre>
  
  <p>I have added #{title} where I would like my song title to appear, sadly though I am unable to get this populate.</p>
  
  <p>My Dj's use BUTT and the show title is connected as part of their connection, so the data should be available pre recording.</p>
  
  <p>Any advice is much appreciated! </p>