Is it possible to force transformers pre-run on server side ?

[semiaddict]

Hi,
I am trying to add information to some documents when parsed (such as video file durations).
The added information relies on server-side code to read files and analyse their contents.

Is is possible to force transformers to only run on the server side?
Maybe via pre-rendering ?

Any help is appreciated.

[semiaddict]

The transformers seem to be already pre-rendering in static mode.
I simply had a typo that prevented the information from being correctly assigned to the content.