[prev in list] [next in list] [prev in thread] [next in thread] 

List:       apache-modperl
Subject:    Re: passing data between connection and http filters
From:       Stas Bekman <stas () stason ! org>
Date:       2004-05-27 23:04:36
Message-ID: 40B67404.5040301 () stason ! org
[Download RAW message or body]

Eric J. Hansen wrote:
> I have an application that uses mod_proxy (as a reverse proxy) to fetch content
> from a back-end server.  My application needs to do some manipulation of both
> the request headers and the response body.  Given that mod_proxy circumvents
> most of mod_perl's handler phases, I'm having to use filters to do what I need
> to do.
> 
> To manipulate the request headers, I'm using Stas' HTTPHeadersFixup module (i.e.,
> I set Accept-Encoding: none, etc.)  Then I'm using a HTTP output filter to
> analyze & modify the actual content as its being sent back to the browser.
> 
> The question I have is how to pass data between the input connection filter
> and the output http filter.  For example, I'd like to set a yes/no flag, or even
> a hash reference, and then retrieve it from the output filter. Ordinarily, I would
> happily use notes/pnotes to do this, but since connection filters don't have
> access to the $r object, this doesn't fly.  Any ideas for doing this conveniently,
> short of using an external memory/db cache?

Yes, but you have connection notes, which work exactly like request notes but 
you call them on the connection object.
http://perl.apache.org/docs/2.0/api/Apache/Connection.html#C_notes_
The only problem you have with that is the need to know when to reset those 
notes, since with KeepAlive you will have more than one request coming over 
the same connection. It's a bit tricky, but it's explained here:
http://perl.apache.org/docs/2.0/user/handlers/filters.html#Connection_Filters_over_KeepAlive_Connections

Apache::Filter::HTTPHeadersFixup uses this exact communication technique that 
you are talking about.

-- 
__________________________________________________________________
Stas Bekman            JAm_pH ------> Just Another mod_perl Hacker
http://stason.org/     mod_perl Guide ---> http://perl.apache.org
mailto:stas@stason.org http://use.perl.org http://apacheweek.com
http://modperlbook.org http://apache.org   http://ticketmaster.com

-- 
Report problems: http://perl.apache.org/bugs/
Mail list info: http://perl.apache.org/maillist/modperl.html
List etiquette: http://perl.apache.org/maillist/email-etiquette.html

[prev in list] [next in list] [prev in thread] [next in thread]