django-lazy-tags

A Django app for easily loading template tags via AJAX.

Installation

1. Install via pip

pip install django-lazy-tags

2. Add to installed apps

INSTALLED_APPS = (
    # ...
    'lazy_tags',
)

3. Add the lazy tags urls to your root urlconf.

urlpatterns = patterns('',
    # ...
    url(r'^lazy_tags/', include('lazy_tags.urls')),
)

Usage

First, load the lazy_tags library in your templates.

{% load lazy_tags %}

Then, call the lazy_tag template tag passing your tag name as the first parameter. The format is tag_library.tag_name where tag_library is what you would load at the top of the page (e.g. my_tags) and tag_name is the name of your template tag (e.g. my_template_tag). After the first argument to lazy_tag simply pass the rest of the args and kwargs just as you would pass them to your own tag.

This:

{% load my_tags %}

{% my_template_tag arg1 arg2 kw1='hello' kw2='world' %}

Becomes this:

{% load lazy_tags %}

{% lazy_tag 'my_tags.my_template_tag' arg1 arg2 kw1='hello' kw2='world' %}

After placing your template tags in the template you still need to specify where you would like the AJAX JavaScript to output to the page. That is what the lazy_tags_js tag is for:

{% block js-additional %}
  {% lazy_tags_js%}
{% endblock %}

This will spit out the JavaScript required to run the AJAX. The JavaScript changes depending on your LAZY_TAGS_AJAX_JS setting.

The lazy_tag decorator

django-lazy-tags also includes a decorator that can be used on template tags that use simple_tag. When using the lazy_tag decorator you can use your template tags exactly the same as before and they will use AJAX.

from lazy_tags.decorators import lazy_tag

@register.simple_tag
@lazy_tag
def show_user(pk):
    user = User.objects.get(pk=pk)
    return render_to_string('user/show_user.html', {
        'user': user,
    })

There are a few caveats with this method. First, the decorator currently only works with tags that use simple_tag. Hopefully this will work with inclusion_tag in the future. Secondly, the lazy_tag decorator must come after the simple_tag decorator.

Settings

LAZY_TAGS_AJAX_JS

The library to use to run AJAX. Options are 'javascript', 'jquery', or 'prototype'. Defaults to 'jquery'.

LAZY_TAGS_CACHE_TIMEOUT

The timeout on each lazy tag cache. Defaults to 60 (seconds).

LAZY_TAGS_ERROR_MESSAGE

The error message to display if the AJAX request fails. Defaults to 'An error occurred.'

Customizing the Loading Animation

This is the default HTML on the page before the AJAX request completes:

<div id="{{ tag_id }}" class="lazy-tag">
    <div class="lazy-tag-spinner-container"
         style="width: 100%; text-align: center;">
        <img id="{{ tag_id }}-spinner" class="lazy-tag-spinner"
             style="width: 15px; height: 15px;"
             src="{static_url}img/lazy_tags/spinner.gif" />
    </div>
</div>

To customize the loading animation, override the lazy-tag, lazy-tag-spinner-container, or lazy-tag-spinner classes in your CSS.

Current Limitations

• Does not work with tags that take context.
• Template tag arguments must be serializable (str, unicode, int, float, etc.).