autobreadcrumbs 2.0.0

Django application to add breadcrumbs to your pages

Introduction

AutoBreadcrumbs is a Django application to automatically build a breadcrumb in your website like this :

Home > Some page > Some child page

Each crumb displays a title with a link to represent a view, the crumb tree is determined from the urls map of your project, their titles and links are determined from the associated view entries in the breadcrumbs registry.

Requires

Since the 0.9 version, it requires at least Django 1.5, for Django 1.4 you will have to use the 0.8.1.1, you can find him in the github releases.

Links

• Download his PyPi package;

• Clone it on his Github repository;

Install

In your settings file add AutoBreadcrumbs to your installed apps :

INSTALLED_APPS = (
    ...
    'autobreadcrumbs',
    ...
)

Import default settings:

from autobreadcrumbs.settings import *

Then register his context processor :

TEMPLATE_CONTEXT_PROCESSORS = (
    ...
    'autobreadcrumbs.context_processors.AutoBreadcrumbsContext',
    ...
)

And finally, as for the autodiscover for the admin site (django.contrib.admin), you will have to add these two lines in your urls.py project :

import autobreadcrumbs
autobreadcrumbs.autodiscover()

This is optional but if you don’t do this, all crumbs.py file will be ignored and only titles defined in settings.AUTOBREADCRUMBS_TITLES will be used.

Usage

Note that this app will don’t work correctly if you don’t have a strong organisation in your urls map.

• You must ensure that all your urls are correctly named (see Naming URL patterns);

• Different views must not use the same url;

• If you use url namespace, prefix all your crumb url name with it;

• Regroup your restricted views on some url paths and don’t mix them with non-restricted view urls.

View registration

Registration

The context processor makes a search from the current url that is splitted in segments which represent the crumbs. For each segment, an entry is searched on his URL name in the breadcrumbs registry in this step order :

1. If the name has an entry in settings.AUTOBREADCRUMBS_TITLES, then use it;

2. If the name has an entry in a crumbs.py file in one of your apps, then use it;

If none of these steps succeeds to find the URL name, the ressource will be ignored and not be displayed in the breadcrumbs.

If you need to hide a ressource from breadcrumbs, just set his URL name to a None value, this will act in ignoring the ressource.

A crumb title value use the Django template system to be rendered and is aware of the context of the template where it is called, so you can use all available template filters, tags and variables in your crumb titles.

Optionally a crumb entry can be a tuple containing the title and callable function :

'documents-private-doc': (ugettext_lazy('Sitemap'), lambda x,y: True),

The callable function is given two arguments, the url name and the Request object. The callable must return a boolean, True if the crumb can be displayed or False if the crumb must be ignored.

This form is generally used to check permission for private views, like this :

def check_crumb_perm(name, request):
    if name == 'documents-private-doc' and request.user.is_anonymous():
        return False
    return True

AUTOBREADCRUMBS_TITLES = {
    ...
    'documents-private-doc': (ugettext_lazy('Sitemap'), lambda x,y: True),
    ...
}

App crumbs

Applications should define their crumbs in a crumbs.py file like this :

from autobreadcrumbs import site
from django.utils.translation import ugettext_lazy

site.update({
    ...
    'documents-index': ugettext_lazy('Sitemap'),
    ...
})

Note the usage of ugettext_lazy to get translated strings, if you don’t use the Django internationalization system in your project you can avoid it, but if you plan to use it you must apply ugettext_lazy on your title strings.

Project crumbs

Also you can register crumbs in your project settings :

AUTOBREADCRUMBS_TITLES = {
    "pages-index1": u"My index",
    "pages-index2": u"My index alternative",
}

Crumbs setted in project settings have the higher priority on application crumbs. As for App crumbs you should use ugettext_lazy on your title strings.

Crumbs with URL namespace

If you use URL namespace on some views, remember to prefixed their crumb’s url name with the namespace followed by a colon character, like this :

AUTOBREADCRUMBS_TITLES = {
    ...
    "mynamespace:pages-index1": u"My index",
    ...
}

If you forget to do this, your crumb won’t be finded or be filled with a wrong crumb (from an another app view with the same url name but without the namespace).

Template context

In all your templates laying that have the global context, two additional variables (autobreadcrumbs_elements and autobreadcrumbs_current) will be added by the context processor.

autobreadcrumbs_elements

This variable will contain the breadcrumb as a list of crumbs in the correct order, where each crumb will be a BreadcrumbRessource instance. A BreadcrumbRessource instance contains the following attributes :

• path : relative path to the ressource URL;

• name : the ressource name (that is the name of the URL linked to the ressource), prefixed with the namespace if any;

• title : the ressource title to be displayed;

• view_args : argument list given to the ressource view;

• view_kwargs : named argument list given to the ressource view;

autobreadcrumbs_current

This variable will contains the BreadcrumbRessource instance of the current crumb, this instance is the same as the last list item in the autobreadcrumbs_elements.

Template tags

These tags are avalaible after loading their library in your templates :

{% load autobreadcrumb %}

current_title_from_breadcrumbs

This simply returns the title from the current ressource.

autobreadcrumbs_tag

Builds the breadcrumb HTML using the autobreadcrumbs_tag.html template.

autobreadcrumbs_links

Builds the breadcrumb HTML using the template strings in settings.AUTOBREADCRUMBS_HTML_LINK and settings.AUTOBREADCRUMBS_HTML_SEPARATOR.

currentwalkthroughto

Returns the content tag if the current ressource walk through the given ressource URL name.

Example :

{% currentwalkthroughto 'index' %}This pas walk through the named url 'index'{% endcurrentwalkthroughto %}

If the test fail, the tag return an empty string.