### Angular interceptor

# http_interceptor source

  The http interceptor for all requests and responses to check and config payload and response objects.

  - To prevent OPTIONS preflight request change header Content-Type to `text/plain`.
  - 4xx - 5xx errors are handled in response objects.
  - `_debug_queries` is helper object for development purposes to see how long the queries lasts. They are shown in /debug/list' page.
  - API returns `is_login` key to check if current user is authenticated. Interceptor checks and if not logged in redirects to login page.