Multiple youtube_api.cr helper fixes

Add documentation
Bump web client version string
Add charset=UTF-8 to the 'content-type' header
Parse JSON and return it as a Hash
Handle API error messages

src/invidious/helpers/youtube_api.cr

@@ -4,8 +4,18 @@
 
 # Hard-coded constants required by the API
 HARDCODED_API_KEY     = "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8"
-HARDCODED_CLIENT_VERS = "2.20210318.08.00"
+HARDCODED_CLIENT_VERS = "2.20210330.08.00"
 
+####################################################################
+# request_youtube_api_browse(continuation)
+#
+# Requests the youtubei/vi/browse endpoint with the required headers
+# to get JSON in en-US (english US).
+#
+# The requested data is a continuation token (ctoken). Depending on
+# this token's contents, the returned data can be comments, playlist
+# videos, search results, channel community tab, ...
+#
 def request_youtube_api_browse(continuation)
   # JSON Request data, required by the API
   data = {
@@ -20,12 +30,23 @@ def request_youtube_api_browse(continuation)
     "continuation": continuation,
   }
 
-  # Send the POST request and return result
+  # Send the POST request and parse result
   response = YT_POOL.client &.post(
     "/youtubei/v1/browse?key=#{HARDCODED_API_KEY}",
-    headers: HTTP::Headers{"content-type" => "application/json"},
+    headers: HTTP::Headers{"content-type" => "application/json; charset=UTF-8"},
     body: data.to_json
   )
 
-  return response.body
+  initial_data = JSON.parse(response.body).as_h
+
+  # Error handling
+  if initial_data.has_key?("error")
+    code = initial_data["error"]["code"]
+    message = initial_data["error"]["message"].to_s.sub(/(\\n)+\^$/, "")
+
+    raise InfoException.new("Could not extract JSON. Youtube API returned \
+      error #{code} with message:<br>\"#{message}\"")
+  end
+
+  return initial_data
 end