Add new audioscrobbler implementation.

src/libs/extra/audioscrobbler.liq

@@ -0,0 +1,398 @@
+let error.audioscrobbler = error.register("audioscrobbler")
+
+let settings.audioscrobbler =
+  settings.make.void(
+    "Audioscrobbler settings"
+  )
+
+let settings.audioscrobbler.api_key =
+  settings.make(
+    description=
+      "Default API key for audioscrobbler",
+    ""
+  )
+
+let settings.audioscrobbler.api_secret =
+  settings.make(
+    description=
+      "Default API secret for audioscrobbler",
+    ""
+  )
+
+audioscrobbler = ()
+
+def audioscrobbler.request(
+  ~base_url="http://ws.audioscrobbler.com/2.0",
+  ~api_key=null(),
+  ~api_secret=null(),
+  params
+) =
+  api_key = api_key ?? settings.audioscrobbler.api_key()
+  api_secret = api_secret ?? settings.audioscrobbler.api_secret()
+
+  if
+    api_key == "" or api_secret == ""
+  then
+    error.raise(
+      error.audioscrobbler,
+      "`api_key` or `api_secret` missing!"
+    )
+  end
+
+  params = [("api_key", api_key), ...params]
+
+  sig_params = list.sort(fun (v, v') -> string.compare(fst(v), fst(v')), params)
+  sig_params = list.map(fun (v) -> "#{fst(v)}#{(snd(v) : string)}", sig_params)
+  sig_params = string.concat(separator="", sig_params)
+
+  api_sig = string.digest("#{sig_params}#{api_secret}")
+
+  http.post(
+    base_url,
+    headers=[("Content-Type", "application/x-www-form-urlencoded")],
+    data=http.www_form_urlencoded([...params, ("api_sig", api_sig)])
+  )
+end
+
+def audioscrobbler.check_response(resp) =
+  let xml.parse ({lfm = {xml_params = {status}}} :
+    {lfm: {xml_params: {status: string}}}
+  ) = resp
+  if
+    (status == "failed")
+  then
+    error_ref = error
+    let xml.parse ({lfm = {error = {xml_params = {code}}}} :
+      {lfm: {error: string.{ xml_params: {code: int} }}}
+    ) = resp
+    error_ref.raise(
+      error_ref.audioscrobbler,
+      "Error #{code}: #{error}"
+    )
+  end
+end
+
+def audioscrobbler.auth(
+  ~username,
+  ~password,
+  ~api_key=null(),
+  ~api_secret=null()
+) =
+  resp =
+    audioscrobbler.request(
+      api_key=api_key,
+      api_secret=api_secret,
+      [
+        ("method", "auth.getMobileSession"),
+        ("username", username),
+        ("password", password)
+      ]
+    )
+
+  audioscrobbler.check_response(resp)
+
+  try
+    let xml.parse ({lfm = {session = {name, key}}} :
+      {lfm: {session: {name: string, key: string}}}
+    ) = resp
+    assert(name == username)
+    key
+  catch err do
+    error.raise(
+      error.invalid,
+      "Invalid response: #{resp}, error: #{err}"
+    )
+  end
+end
+
+let audioscrobbler.api = {track=()}
+
+# Submit a track to the audioscrobbler
+# `track.updateNowPlaying` API.
+# @category Interaction
+def audioscrobbler.api.track.updateNowPlaying(
+  ~username,
+  ~password,
+  ~session_key=null(),
+  ~api_key=null(),
+  ~api_secret=null(),
+  ~artist,
+  ~track,
+  ~album=null(),
+  ~context=null(),
+  ~trackNumber=null(),
+  ~mbid=null(),
+  ~albumArtist=null(),
+  ~duration=null()
+) =
+  session_key =
+    session_key
+      ??
+        audioscrobbler.auth(
+          username=username,
+          password=password,
+          api_key=api_key,
+          api_secret=api_secret
+        )
+
+  params =
+    [
+      ("track", track),
+      ("artist", artist),
+      ...(null.defined(album) ? [("album", null.get(album))] : [] ),
+      ...(null.defined(context) ? [("context", null.get(context))] : [] ),
+      ...(
+        null.defined(trackNumber)
+        ? [("trackNumber", string((null.get(trackNumber) : int)))] : []
+      ),
+      ...(null.defined(mbid) ? [("mbid", null.get(mbid))] : [] ),
+      ...(
+        null.defined(albumArtist)
+        ? [("albumArtist", null.get(albumArtist))] : []
+      ),
+      ...(
+        null.defined(duration)
+        ? [("duration", string((null.get(duration) : int)))] : []
+      )
+    ]
+
+  log.info(
+    label="audioscrobbler.api.track.updateNowPlaying",
+    "Submitting updateNowPlaying with: #{params}"
+  )
+
+  resp =
+    audioscrobbler.request(
+      api_key=api_key,
+      api_secret=api_secret,
+      [...params, ("method", "track.updateNowPlaying"), ("sk", session_key)]
+    )
+
+  audioscrobbler.check_response(resp)
+
+  try
+    let xml.parse (v :
+      {
+        lfm: {
+          nowplaying: {
+            track: string.{ xml_params: {corrected: string} },
+            artist: string.{ xml_params: {corrected: string} },
+            album: string?.{ xml_params: {corrected: string} },
+            albumArtist: string?.{ xml_params: {corrected: string} },
+            timestamp: string,
+            ignoredMessage: {xml_params: {code: string}}
+          },
+          xml_params: {status: string}
+        }
+      }
+    ) = resp
+
+    log.info(
+      label="audioscrobbler.api.track.updateNowPlaying",
+      "Done submitting updateNowPlaying with: #{params}"
+    )
+
+    v
+  catch err do
+    error.raise(
+      error.invalid,
+      "Invalid response: #{resp}, error: #{err}"
+    )
+  end
+end
+
+# Submit a track to the audioscrobbler
+# `track.scrobble` API.
+# @category Interaction
+def audioscrobbler.api.track.scrobble(
+  ~username,
+  ~password,
+  ~session_key=null(),
+  ~api_key=null(),
+  ~api_secret=null(),
+  ~artist,
+  ~track,
+  ~timestamp=time(),
+  ~album=null(),
+  ~context=null(),
+  ~streamId=null(),
+  ~chosenByUser=true,
+  ~trackNumber=null(),
+  ~mbid=null(),
+  ~albumArtist=null(),
+  ~duration=null()
+) =
+  session_key =
+    session_key
+      ??
+        audioscrobbler.auth(
+          username=username,
+          password=password,
+          api_key=api_key,
+          api_secret=api_secret
+        )
+
+  params =
+    [
+      ("track", track),
+      ("artist", artist),
+      ("timestamp", string(timestamp)),
+      ...(null.defined(album) ? [("album", null.get(album))] : [] ),
+      ...(null.defined(context) ? [("context", null.get(context))] : [] ),
+      ...(null.defined(streamId) ? [("streamId", null.get(streamId))] : [] ),
+
+      ("chosenByUser", chosenByUser ? "1" : "0" ),
+      ...(
+        null.defined(trackNumber)
+        ? [("trackNumber", string((null.get(trackNumber) : int)))] : []
+      ),
+      ...(null.defined(mbid) ? [("mbid", null.get(mbid))] : [] ),
+      ...(
+        null.defined(albumArtist)
+        ? [("albumArtist", null.get(albumArtist))] : []
+      ),
+      ...(
+        null.defined(duration)
+        ? [("duration", string((null.get(duration) : int)))] : []
+      )
+    ]
+
+  log.info(
+    label="audioscrobbler.api.track.scrobble",
+    "Submitting updateNowPlaying with: #{params}"
+  )
+
+  resp =
+    audioscrobbler.request(
+      api_key=api_key,
+      api_secret=api_secret,
+      [...params, ("method", "track.scrobble"), ("sk", session_key)]
+    )
+
+  audioscrobbler.check_response(resp)
+
+  try
+    let xml.parse (v :
+      {
+        lfm: {
+          scrobbles: {
+            scrobble: {
+              track: string.{ xml_params: {corrected: string} },
+              artist: string.{ xml_params: {corrected: string} },
+              album: string?.{ xml_params: {corrected: string} },
+              albumArtist: string?.{ xml_params: {corrected: string} },
+              timestamp: string,
+              ignoredMessage: {xml_params: {code: string}}
+            },
+            xml_params: {ignored: string, accepted: string}
+          },
+          xml_params: {status: string}
+        }
+      }
+    ) = resp
+
+    log.info(
+      label="audioscrobbler.api.track.scrobble",
+      "Done submitting updateNowPlaying with: #{params}"
+    )
+
+    v
+  catch err do
+    error.raise(
+      error.invalid,
+      "Invalid response: #{resp}, error: #{err}"
+    )
+  end
+end
+
+let source_on_end = source.on_end
+let source_on_metadata = source.on_metadata
+
+# Submit songs using audioscrobbler, respecting the full protocol:
+# First signal song as now playing when starting, and
+# then submit song when it ends.
+# @category Interaction
+# @flag extra
+# @param ~source Source for tracks. Should be one of: "broadcast", "user", "recommendation" or "unknown". Since liquidsoap is intended for radio broadcasting, this is the default. Sources other than user don't need duration to be set.
+# @param ~delay Submit song when there is only this delay left, in seconds.
+# @param ~force If remaining time is null, the song will be assumed to be skipped or cut, and not submitted. Set this to `true` to prevent this behavior
+def audioscrobbler.submit(
+  ~username,
+  ~password,
+  ~api_key=null(),
+  ~api_secret=null(),
+  ~delay=10.,
+  ~force=false,
+  s
+) =
+  session_key =
+    audioscrobbler.auth(
+      username=username,
+      password=password,
+      api_key=api_key,
+      api_secret=api_secret
+    )
+
+  def apply_meta(fn, m) =
+    def c(v) =
+      v == "" ? null() : v
+    end
+    track = m["title"]
+    album = c(m["album"])
+    artist = m["artist"]
+    trackNumber =
+      try
+        null.map(int_of_string, c(m["tracknumber"]))
+      catch _ do
+        null()
+      end
+    albumArtist = c(m["albumartist"])
+    ignore(
+      fn(
+        username=username,
+        password=password,
+        api_key=api_key,
+        api_secret=api_secret,
+        session_key=session_key,
+        track=track,
+        artist=artist,
+        album=album,
+        trackNumber=trackNumber,
+        albumArtist=albumArtist
+      )
+    )
+  end
+
+  def now_playing(m) =
+    try
+      apply_meta(audioscrobbler.api.track.updateNowPlaying, m)
+    catch err do
+      log.important(
+        "Error while submitting nowplaying info for #{source.id(s)}: #{err}"
+      )
+    end
+  end
+
+  s = source_on_metadata(s, now_playing)
+  f =
+    fun (rem, m) ->
+      # Avoid skipped songs
+      if
+        rem > 0. or force
+      then
+        try
+          apply_meta(audioscrobbler.api.track.scrobble, m)
+        catch err do
+          log.important(
+            "Error while submitting scrobble info for #{source.id(s)}: #{err}"
+          )
+        end
+      else
+        log(
+          label="audioscrobbler.submit",
+          level=4,
+          "Remaining time null: will not submit song (song skipped ?)"
+        )
+      end
+  source_on_end(s, delay=delay, f)
+end