How to filter non-http requests

[arc...@gmail.com]

I want to be able to filter non-http requests and especially local
schemes like file: or about: for a kiosk application. For some
schemes, like about:, it is possible to remove the component or
register a fake component using the same contract-id.

The file: scheme seems to be more difficult to remove because if I try
to disable it (by modifying the compreg.dat file) nothing works.
Surely because it is heavily use internally.

So, I'm looking for a way to filter all requests (local and remote,
http and other protocols) in firefox.

- Is there a known way to do that ?
- Is there an API to filter all URI requested by the browser ?
- Is it possible to override the default nsIOSService component to
filter request and forward them to the original one ?

Regards,
-- arcoun