[grilo-plugins/wip/jfelder/theaudiodb-cover: 3/3] lua-factory: Add TheAudioDB cover source

[Victor Toso <victortoso src gnome org>]

commit 0d68f4491da2dc71e52ed75e3f2baeed2fe056d7
Author: Jean Felder <jfelder src gnome org>
Date:   Thu Aug 2 20:20:21 2018 +0200

    lua-factory: Add TheAudioDB cover source
    
    This source allows to download cover art albums from theaudiodb.com
    website.
    Api documentation at https://theaudiodb.com/api_guide.php

 src/lua-factory/sources/grl-theaudiodb-cover.lua | 109 +++++++++++++++++++++++
 src/lua-factory/sources/meson.build              |   1 +
 2 files changed, 110 insertions(+)
---
diff --git a/src/lua-factory/sources/grl-theaudiodb-cover.lua 
b/src/lua-factory/sources/grl-theaudiodb-cover.lua
new file mode 100644
index 0000000..559b9b9
--- /dev/null
+++ b/src/lua-factory/sources/grl-theaudiodb-cover.lua
@@ -0,0 +1,109 @@
+--[[
+ * Copyright © 2018 The Grilo Developers.
+ *
+ * Contact: Jean Felder <jfelder gnome org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+--]]
+
+---------------------------
+-- Source initialization --
+---------------------------
+
+source = {
+  id = "grl-theaudiodb-cover",
+  name = "TheAudioDB Cover",
+  description = "a source for music covers",
+  supported_keys = { 'thumbnail' },
+  supported_media = { 'audio' },
+  config_keys = {
+    required = { "api-key" },
+  },
+  resolve_keys = {
+    ["type"] = "audio",
+    required = { "artist", "album" },
+  },
+  tags = { 'music', 'net:internet' },
+}
+
+netopts = {
+  user_agent = "Grilo Source TheAudioDB/0.3.8",
+}
+
+------------------
+-- Source utils --
+------------------
+theaudiodb = {}
+covers_fields = {"strAlbumThumb", "strAlbumThumbBack", "strAlbumCDart", "strAlbumSpine"}
+
+THEAUDIODB_SEARCH_ALBUM = 'https://theaudiodb.com/api/v1/json/%s/searchalbum.php?s=%s&a=%s'
+
+---------------------------------
+-- Handlers of Grilo functions --
+---------------------------------
+
+function grl_source_init (configs)
+  theaudiodb.api_key = configs.api_key
+  return true
+end
+
+function grl_source_resolve()
+  local url, keys
+  local artist, title
+
+  keys = grl.get_media_keys()
+  if not keys or not keys.artist or not keys.album
+    or #keys.artist == 0 or #keys.album == 0 then
+    grl.callback()
+    return
+  end
+
+  -- Prepare artist and title strings to the url
+  artist = grl.encode(keys.artist)
+  album = grl.encode(keys.album)
+  url = string.format(THEAUDIODB_SEARCH_ALBUM, theaudiodb.api_key, artist, album)
+  grl.fetch(url, fetch_cb, netopts)
+end
+
+---------------
+-- Utilities --
+---------------
+
+function fetch_cb(result)
+  local json = {}
+
+  if not result then
+    grl.callback()
+    return
+  end
+
+  json = grl.lua.json.string_to_table(result)
+  if not json or not json.album or #json.album == 0 then
+    grl.callback()
+    return
+  end
+
+  local media = {}
+  local thumb = {}
+  for _, val in ipairs(covers_fields) do
+    thumb[#thumb + 1] = json.album[val] or nil
+  end
+
+  media.thumbnail = thumb
+
+  grl.callback(media)
+end
diff --git a/src/lua-factory/sources/meson.build b/src/lua-factory/sources/meson.build
index 3c09db0..2da3c3a 100644
--- a/src/lua-factory/sources/meson.build
+++ b/src/lua-factory/sources/meson.build
@@ -17,6 +17,7 @@ sources = [
     'grl-pocket',
     'grl-radiofrance',
     'grl-spotify-cover',
+    'grl-theaudiodb-cover',
     'grl-thegamesdb',
     'grl-video-title-parsing',
 ]