Improve error messages in middleware

**Feature request**
It would be great to have analytics for controllers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_analytics` with default `false`.

No files, tests, or entry points are identified. Start by locating the middleware and controller implementations and the existing configuration handling, then clarify what controller analytics must record and expose. Done is an enable_analytics option with a default of false and the requested analytics behavior, but that behavior is not defined here.

Written by the indexing model from the issue text.