Apache2::DebugFilter 0.02

Apache2::DebugFilter is a Perl module to debug mod_perl and native Apache2 filters.

Synopsis

# 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 => $datan";
}

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

Filter Handlers

snoop_connection()

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

Notice that in order to see requests 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 its 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.

snoop_request()

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

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