Author image Iain Docherty
and 1 contributors

NAME

Catalyst::TraitFor::Controller::Breadcrumb::Followed - Breadcrumb navigation using Moose Roles

SYNOPSIS

This keeps a Breadcrumb trail of pages that have been visited allowing the user to go back to any earlier page directly.

Note that this is different from a Breadcrumb which shows you where you are in a site navigation hierarchy.

In your Catalyst Controller.

    package MyApp::Web::Controller::Root;

    use Moose;
    use namespace::autoclean;

    with 'Catalyst::TraitFor::Controller::BreadCrumb::Followed';

Then later on in your controllers you can do

    sub foo : Local {
        my ($self, $c) = @_;

        $self->breadcrumb_start($c, 'Foo Text');
        ...
    }

    sub bar : Local {
        my ($self, $c) = @_;

        $self->breadcrumb_add($c, 'Bar Text');
        ...
    }

DESCRIPTION

This implementation of Breadcrumb navigation is of the type that shows the user where she has navigated. For example, she may start at a list of Artists, clicking on one of the Artists displays a list of CDs by that Artist. Clicking on a CD displays a list of Tracks on that CD.

The Breadcrumb would hold the route taken (Artists -> Artist -> CD -> Track) and retain that information in session data.

The session data holds a data structure that can be used in a Template to build a list of the visited pages together with navigation links and rendered with suitable CSS.

The class keeps track of which pages have been visited so if a URL that is in the list of Breadcrumbs is re-visited then the Breadcrumb trail is truncated to the first instance.

Whenever the breadcrumb_start method is called, any existing Breadcrumb trail is truncated and a new one is started.

METHODS

Start a new breadcrumb trail.

    sub artists : Local {
        my ($self, $c) = @_;

        $self->breadcrumb_start($c, 'All Artists');
        ...
    }

Calling breadcrumb_start removes any existing breadcrumb trail and starts a new one.

The method takes two parameters, the $c catalyst object and the title to be shown in the breadcrumb trail.

Append to the end of an existing breadcrumb trail.

    sub cds : Local {
        my ($self, $c) = @_;

        $self->breadcrumb_add($c, $artist_name);
        ...
    }

This appends to the existing breadcrumb trail (as started by breadcrumb_start) and adds the current URI to it.

In the event of the user navigating so that she navigates back to a URI she has already visited in the breadcrumb trail, the trail is truncated back to the first instance of that URI.

session data

The Breadcrumb trail is held in the session data, by default it is held in $c->session->{breadcrumb} but this can be configured (see below).

The session data is build up into an array of hashes representing each part of the breadcrumb trail. e.g

    $c->session->{breadcrumb} = [
        {
        class   => 'done',
        uri     => '/artists',
        title   => 'All Artists',
        },
        {
        class   => 'done',
        uri     => '/artist/3',
        title   => 'David Bowie',
        },
        {
        class   => 'lastDone',
        uri     => '/artist/3/cd/4',
        title   => 'Diamond Dogs',
        }
        class   => 'current',
        uri     => '/artist/3/cd/4/track/6',
        title   => 'Rebel Rebel',
        }
    ];

This session data can then be used to create HTML in a Template. One example is as follows.

    <div class="navigation">
      <ul id="mainNav" class="breadcrumb">
    [% FOREACH crumb IN c.session.breadcrumb %]
        <li class="[% crumb.class %]">
      [% IF crumb.class=='lastDone' || crumb.class=='done' %]
        [% back_uri = crumb.uri %]
          <a href="[% crumb.uri %]">[% crumb.title %]</a>
      [% ELSE %]
          [% crumb.title %]
      [% END %]
        </li>
    [% END %]
      </ul>

    [% IF back_uri %]
      <div class="navigation_buttons">
        <button class="button_previous" onClick="parent.location='[% back_uri %]'"> Back </button>
      </div>
    [% END %]
    </div>

The use of suitable CSS can be used to display this in whatever form you wish.

configuration

By default the breadcrumb is held in $c->session->{breadcrumb} but you can change this in your configuration in your application.

    package MyApp::Web;

    ...

    __PACKAGE__->config->{'Catalyst::TraitFor::Controller::Breadcrumb::Followed'} = {
        session_name => 'my_breadcrumb_trail',
    };

AUTHOR

Ian Docherty pause@icydee.com

COPYRIGHT & LICENSE

    Copyright (c) 2010 the aforementioned authors. All rights
    reserved. This program is free software; you can redistribute
    it and/or modify it under the same terms as Perl itself.