Dezi::Aggregator - document aggregation base class


 package MyAggregator;
 use Moose;
 extends 'Dezi::Aggregator';

 sub get_doc {
    my ($self, $url) = @_;

    # do something to create a Dezi::Indexer::Doc object from $url

    return $doc;

 sub crawl {
    my ($self, @where) = @_;

    foreach my $place (@where) {

       # do something to search $place for docs to pass to get_doc()




Dezi::Aggregator is a base class that defines the basic API for writing an aggregator. Only two methods are required: get_doc() and crawl(). See the SYNOPSIS for the prototypes.

See Dezi::Aggregator::FS and Dezi::Aggregator::Spider for examples of aggregators that crawl the filesystem and web, respectively.



Set object flags per Dezi::Class API. These are also accessors, and include:


This will set the parser() value in swish_filter() based on the MIME type of the doc_class() object.


A Dezi::Indexer object.


The name of the Dezi::Indexer::Doc-derived class to use in get_doc(). Default is Dezi::Indexer::Doc.


A SWISH::Filter object. If not passed in new() one is created for you.


Dry run mode, just prints info on stderr but does not build index.


Value should be a CODE ref. This is passed through to set_filter() internally at BUILD() time. If you need to adjust the filter after the Aggregator object is created, use set_filter().


Value should be a Unix timestamp (epoch seconds). Default is undef. If set, aggregators should skip files that have a modification time older than the timestamp.

You may get/set the ok_if_newer_than value with the ok_if_newer_than() attribute method, but use set_ok_if_newer_than() to include validation of the supplied timestamp value.

progress( Term::ProgressBar object )

Get/set a progress object. The default used in the examples/swish3 script is Term::ProgressBar. If set, it will be incremented just like count() is.


Returns the Dezi::Indexer::Config object from the Indexer being used. This is a read-only method (accessor not mutator).


Returns the total number of doc_class() objects returned by get_doc().

crawl( @where )

Override this method in your subclass. It does the aggregation, and passes each doc_class() object from get_doc() to indexer->process().

get_doc( url )

Override this method in your subclass. Should return a doc_class() object.

swish_filter( doc_class_object )

Passes the content() of the doc_class_object through SWISH::Filter and transforms it to something index-able. Returns the doc_class_object, filtered.

NOTE: This method should be called by all aggregators after get_doc() and before passing to the indexer().

See the SWISH::Filter documentation.

set_filter( code_ref )

Use code_ref as the doc_class filter. This method called by BUILD() if filter param set in constructor.

set_ok_if_newer_than( timestamp )

Set the ok_if_newer_than attribute. timestamp should be a Unix epoch value.


Peter Karman, <>


Please report any bugs or feature requests to bug-swish-prog at, or through the web interface at I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.


You can find documentation for this module with the perldoc command.

    perldoc Dezi

You can also look for information at:


Copyright 2008-2018 by Peter Karman

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