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1 non-PAUSE user
Author image Julien Fiegehenn
and 1 contributors


CatalystX::DebugFilter - Provides configurable filtering of data that is logged to the debug logs (and error screen)


version 0.16


    package MyApp;

    use Catalyst;
    with 'CatalystX::DebugFilter';

        'CatalystX::DebugFilter' => {

            # filter all "Cookie" headers as well as "password" and "SECRET" parameters
            Request => { headers => 'Cookie', params => [ 'password', qr/SECRET/ ] },

            # filter all Set-Cookie values in the response
            Response => { headers => 'Set-Cookie' },

            Stash => [
                sub {
                    my ( $key, $value ) = @_;
                    my $type = ref($value);

                    # ignore any non-ref values
                    return undef if !$type;

                    if ( $type->isa('DBIx::Class::ResultSet') ) {    # dump ResultSet objects as SQL
                        return $value->as_query;
                    } elsif ( $type->isa('DBIx::Class::Result') ) {    # dump Result objects as simple HASH
                        return { $value->get_columns };
                    } else {                                           # ignore these
                        return undef;
            Session => [


This module provides a Moose role that will filter certain elements of a request/response/stash/session before they are logged to the debug logs (or the error screen).



This role uses an "around" method modifier on the "dump_these" in Catalyst method and modifies the elements returned according to the configuration provided by the user as demonstrated in the SYNOPSIS section.


There are few different types of filters that can be defined:

  • Exact Match

    The parameter/header/stash key is compared against a literal string. If it matches, the value is replaced with [FILTERED]

  • Regular Expression

    The parameter/header/stash key is compared against a regular expression. If it matches, the value is replaced with [FILTERED]

  • Callback

    The parameter/header/stash key and value are passed to a callback function. If the function returns a defined value, that value is used instead of the original value.

This module supports filtering a few different types of data (naturally, these could all be combined into a single config call):

  • Request Parameters

        __PACKAGE__->config( 'CatalystX::DebugFilter' => { Request => { params => $filters } } );
  • Request Headers

    Useful with CatalystX::Debug::RequestHeaders:

        __PACKAGE__->config( 'CatalystX::DebugFilter' => { Request => { headers => $filters } } );
  • Response Headers

    Useful with CatalystX::Debug::ResponseHeaders:

        __PACKAGE__->config( 'CatalystX::DebugFilter' => { Response => { headers => $filters } } );
  • Stash Data

        __PACKAGE__->config( 'CatalystX::DebugFilter' => { Stash => $filters } );

In each of the above examples, $filters can be one of a few things:

  • A non-ref scalar, implying an exact match

  • A Regexp reference, implying an regular expression match

  • A CODE reference, implying a callback matching function

  • An ARRAY reference of any of the above


This module will not magically remove all references to a specific piece of data unless filters are explicitly defined for each place this data is stored. For instance, you may define a request parameter filter to prevent passwords from being logged to the debug logs but if you create an object that contains that password and store it in the stash, the password value may still appear on the error screen.

Also, the stash and session are only filtered at the top level. If you would like to filter more extensively, you can use a filter callback to traverse the hash, modifying whatever data you like (a shallow copy is made before passing the value to the callback).



Brian Phillips <bphillips@cpan.org>


This software is copyright (c) 2018 by Brian Phillips.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.