django-async-include 0.2

A simple application for Django to include (and fetch) asynchronous templates.

django-async-include

Asynchronous inclusion of Django templates

What’s this?

This is a project to help the ajax load of chunks of HTML with minimal effort on the developer side, providing an easy way to improve web-site experience for your users by minimizing perceived loading times.

This is the development repository.

How does it work?

The async_include template tag sends the context to the server using an AJAX request.

In the case of model objects, it sends the model, application and id. In the case of QuerySets, it sends the encrypted parametriced SQL. Of course, in the case of safe values like strings, booleans or numbers this data are send “as is”.

The receiver is a basic view of this application that renders the template with the received context and returns it in the AJAX call.

Requirements

This application only depends on pycryptodome and jsonpickle.

Of course you will need Django version 1.10 or newer. I have no tested in lower versions of Django but it should work fine with versions from 1.8 to 1.9.

jQuery

Having said that, this application needs jQuery to fetch the templates. So make sure you have jquery loaded in your HEAD HTML section.

The easiest way of inclue jQuery in your project is by loading it from a CDN:

<script
  src="https://code.jquery.com/jquery-3.1.1.min.js"
  integrity="sha256-hVVnYaiADRTO2PzUGmuLJr8BLUSjGIZsDYGmIJLv2b8="
  crossorigin="anonymous"></script>

Beware of the version of jQuery if you are using bootstrap or other framework that can’t work with jQuery’s last version.

Fontawesome (optional)

Fontawesome is the the-facto standard of font icons of our time. Include it in your project to see the spinner moving when loading the remote templates.

The easiest way to include it by using a CDN. For example, bootstrap CDN (not afiliated nor they endorse this project) is one of the most known.

Default waiting spinner uses fontawesome. You can overwrite async_include/spinner.html template if don’t want to use the default fontawesome style.

Installation

Using pip

This package is in pypi so you only have to write:

pip install django-async-include

to install it.

Install master version

Include this code in your requirements.txt file:

-e git://github.com/diegojromerolopez/django-async-include.git#egg=django_async_include

Installation in your Django project

Include the application in your project’s settings.py:

INSTALLED_APPS = [
    ## ...
    'async_include',
]

Include django-async-include URLs

Include the URLs of Django-Async-Include in your urls.py project in the namespace async_include:

urlpatterns = [
    # ...
    url(r'^async_include/', include('async_include.urls', namespace="async_include")),
]

Use

Load the async_include template tags at the top of your file and use the async_include template tag as a replacement of the django include template tag.

You have to pass the local context explicitily to the async included templates, so you can pass all variables you need in your included template as named parameters of the async_include template tag.

{# Load the async_include template tag at the top of your template file #}
{% load async_include %}

{# Call the async_include template tag indicating what objects needs to replace it #}
{% async_include "<path of the >" <object1_name>=<object1> <object2_name>=<object2> ... <objectN_name>=<objectN>  %}

Warning and limitations

Object dynamic attributes

No dynamic attribute will be passed to the templates given that only a reference to it is passed from the caller to the included template callee. Don’t use dynamic attributes inside an async_included template.

Howewer, the full object will be passed to the async_included template, so you could call its methods and properties without any problem.

QuerySets

Each QuerySet is passed as encrypted SQL and converted on the receiver to a RawQuerySet.

RawQuerySet has no len method so length filter returns allways 0.

To fix this we have implemented a new version of the length filter that will be loaded in your template if you overwrite

{% load async_included %}

Note that this templatetag file is async_included, ending in ed.

Examples

Pasing an object

{% load async_include %}

{# .. #}

{# Load the template and informs the board object is required for the included template  #}
{% async_include "boards/components/view/current_percentage_of_completion.html" board=board %}

Pasing a QuerySet

{% load async_include %}

{# .. #}

{% async_include "boards/components/view/summary.html" board=board member=member next_due_date_cards=next_due_date_cards %}

Customization

Spinner

Overwrite async_include/spinner.html template if you want to change the spinner from fontawesome one (default) by a background image or a image. Otherwise, make sure you are loading fontawesome fonts.

Note that the spinner must have class async_included-spinner. Otherwise spinner behavior is going to be impredictable.

Block wrapper html tag

Wrapper tag is div and maybe you don’t want that. Set html__tag optional parameter to the name of the tag you need in that particular context.

Example:

{% load async_include %}

{# .. #}

{# Will be replaced by <li></li> block insted of <div></div> #}
{% async_include "boards/components/view/last_comments.html" board=board html__tag='li' %}

 Request frequency

If do you want to make frequent requests, set request__frequency to the number of seconds you want to make the requests.

Example:

{% load async_include %}

{# .. #}

{# Upate the last comments each 60 seconds #}
{% async_include "boards/components/view/last_comments.html" board=board request__frequency=60 %}

Author

Diego J. Romero López is a Software Engineer at intelligenia.

This project is in no way endorsed or related in any way to my past or current employers.

Contact me by email at [e-mail].

Remove REMOVETHIS to read the real email address.