Re: Activating/decativating PerlOutputFilterHandler "on-the-fly"

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Jeff Ambrosino wrote:
>>From within an existing Perl handler/filter, you can dynamically
> insert ('register') a new filter with the add_output_filter method on
> the request object:
> 
> $r->add_output_filter(\&callback);
> 
> And, you can remove a downstream filter (from within an upstream filter) with:
> 
> $next_f = $f->next;
> $next_f->remove;

And you can also do that from the FilterInitHandler phase
http://perl.apache.org/docs/2.0/user/handlers/filters.html#Filter_Initialization_Phase

> ...or even any subsequent invocations of the current filter (i.e., for
> the current request) with:
> 
> $f->remove;
> 
> n.b. I'm not sure if it is possible to remove a downstream filter from
> within a handler, since it appears you need the $f (filter) object to
> do a remove... (can one reference the filter object from the request
> object?)

It's possible, since you can traverse the filter chain using the ->next 
http://perl.apache.org/docs/2.0/api/Apache/Filter.html#C_next_
and you can access the filter stack with ->input_filters:
http://perl.apache.org/docs/2.0/api/Apache/Connection.html#C_input_filters_
http://perl.apache.org/docs/2.0/api/Apache/RequestRec.html#C_input_filters_
and ->output_filters:
http://perl.apache.org/docs/2.0/api/Apache/Connection.html#C_output_filters_
http://perl.apache.org/docs/2.0/api/Apache/RequestRec.html#C_output_filters_

> For more explanation that will probably put you on the right track, see:
> http://perl.apache.org/docs/2.0/api/Apache/Filter.html

and http://perl.apache.org/docs/2.0/user/handlers/filters.html

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