Now let's talk about a totally new feature of mod_perl 2.0: input/output filtering.

As of this writing the mod_perl filtering API hasn't been finalized, and it's possible that it will change by the time the production version of mod_perl 2.0 is released. However, most concepts presented here won't change, and you should find the discussion and the examples useful for understanding how filters work. For the most up-to-date documentation, refer to