Request Interceptors for Cloud Endpoints in Google App Engine with Java

Question

I am using Cloud Endpoints in Google App Engine with Java. I would like to know how can I intercept a request, add some attributes and pass it to the API calls.

I tried using filters, but they don't seems to work with Google Cloud Endpoints.
https://stackguides.com/questions/34653976/why-appengine-modifies-servlet-attributes-set-by-a-filter

Is there any other idea?

Answer 1

It seems AppEngine cleans up the extra attributes added to the request before passing to the API.
It also adds some of its own attributes to the attributes map, which are available at API level but has nothing useful to me.

So I ended up extracting the headers at each API level and use them.