Add methods for getCatalogSongs & getCatalogAlbums

Allowing to fetch multiple songs or albums at once by providing a string of ids

src/AppleMusicAPI.php

@@ -168,6 +168,27 @@ public function getCatalogAlbum(string $storefront, string $albumId, array $incl
 
         return $this->client->apiRequest('GET', $requestUrl);
     }
+
+    /**
+     * Fetch one or more albums by using their identifiers.
+     * https://developer.apple.com/documentation/applemusicapi/get_multiple_catalog_albums
+     *
+     * @param string $storefront An iTunes Store territory, specified by an ISO 3166 alpha-2 country code.
+     * @param string $albumIds The unique identifiers for the albums. The maximum fetch limit is 100.
+     * @param array  $include A list of additional relationships to include in the fetch.
+     *
+     * @return array|object
+     *
+     * @throws AppleMusicAPIException
+     */
+    public function getCatalogAlbums(string $storefront, string $albumIds, array $include = [])
+    {
+        $requestUrl = sprintf('catalog/%s/albums', $storefront);
+
+        $requestUrl .= '?' . urldecode(http_build_query(['ids' => $albumIds, 'include' => implode(',', $include)]));
+
+        return $this->client->apiRequest('GET', $requestUrl);
+    }
 
     /**
      * Fetch albums by a UPC.
@@ -215,6 +236,27 @@ public function getCatalogSong(string $storefront, string $songId, array $includ
         return $this->client->apiRequest('GET', $requestUrl);
     }
 
+    /**
+     * Fetch one or more songs by using their identifiers.
+     * https://developer.apple.com/documentation/applemusicapi/get_multiple_catalog_songs_by_id
+     *
+     * @param string $storefront An iTunes Store territory, specified by an ISO 3166 alpha-2 country code.
+     * @param string $songIds The unique identifiers for the songs. The maximum fetch limit is 300.
+     * @param array  $include A list of additional relationships to include in the fetch.
+     *
+     * @return array|object
+     *
+     * @throws AppleMusicAPIException
+     */
+    public function getCatalogSongs(string $storefront, string $songIds, array $include = [])
+    {
+        $requestUrl = sprintf('catalog/%s/songs', $storefront);
+
+        $requestUrl .= '?' . urldecode(http_build_query(['ids' => $songIds, 'include' => implode(',', $include)]));
+
+        return $this->client->apiRequest('GET', $requestUrl);
+    }
+
     /**
      * Fetch songs by an ISRC.
      * https://developer.apple.com/documentation/applemusicapi/get_multiple_catalog_songs_by_isrc