Apache2::DebugFilter - Debug mod_perl and native Apache2 filters

  # httpd.conf
  # ----------
  PerlModule Apache2::DebugFilter
  # Connection snooping (everything)
  PerlInputFilterHandler  Apache2::DebugFilter::snoop_connection
  PerlOutputFilterHandler Apache2::DebugFilter::snoop_connection

  # HTTP Request snooping (only HTTP request body)
  <Location /foo>
      PerlInputFilterHandler  Apache2::DebugFilter::snoop_request
      PerlOutputFilterHandler Apache2::DebugFilter::snoop_request
  </Location>

  # in handlers
  #------------
  use Apache2::DebugFilter;
  # convert bb to an array of bucket_type => data pairs
  my $ra_data = Apache2::DebugFilter::bb_dump($bb);
  while (my($btype, $data) = splice @data, 0, 2) {
      print "$btype => $data\n";
  }

  # dump pretty formatted bb's content to a filehandle of your choice
  bb_dump($bb, \*STDERR);

The snoop_connection() filter handler snoops on request and response data flow. For example if the HTTP protocol request is filtered it'll show both the headers and the body of the request and response.

Notice that in order to see request's input body, the response handler must consume it.

The same handler is used for input and output filtering. It internally figures out what kind of stream it's working on.

To configure the input snooper, add to the top level server or virtual host configuration in httpd.conf:

  PerlInputFilterHandler  Apache2::DebugFilter::snoop_connection

To snoop on response output, add:

  PerlOutputFilterHandler Apache2::DebugFilter::snoop_connection

Both can be configured at the same time.

If you want to snoop on what an output filter MyApache2::Filter::output does, put the snooper filter after it:

  PerlOutputFilterHandler MyApache2::Filter::output
  PerlOutputFilterHandler Apache2::DebugFilter::snoop_connection

On the contrary, to snoop on what an input filter MyApache2::Filter::input does, put the snooper filter before it:

  PerlInputFilterHandler Apache2::DebugFilter::snoop_connection
  PerlInputFilterHandler MyApache2::Filter::input

This is because snoop_connection is going to be invoked first and immediately call MyApache2::Filter::input the input filter for data. Only when the latter returns, snoop_connection will do its work.

The snoop_request() filter handler snoops only on HTTP request and response bodies. Otherwise it's similar to snoop_connection(). Only normally it's configured for a specific <Location>. For example:

  <Location /foo>
      PerlInputFilterHandler  Apache2::DebugFilter::snoop_request
      PerlOutputFilterHandler Apache2::DebugFilter::snoop_request
  </Location>

  my $ra_data = Apache2::DebugFilter::bb_dump($bb);

If only a bucket brigade $bb is passed, bb_dump will convert bb to an array of bucket_type => data pairs, and return a reference to it. This later can be used as in the following example:

  while (my($btype, $data) = splice @$ra_data, 0, 2) {
      print "$btype => $data\n";
  }

If the second argument (expected to be an open filehandle) is passed, as in:

  Apache2::DebugFilter::bb_dump($bb, \*STDERR);

bb_dump will print pretty formatted bb's content to that filehandle.

Philip M. Gollucci <pgollucci@p6m7g8.com>

Previously developed by Stas Bekman.

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

http://perl.apache.org/docs/2.0/

perl.

The Apache2::DebugFilter module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.