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Overview

In short, django-simple-templates provides easy, designer-friendly templates and A/B testing (split testing) friendly tools for Django. I ran into both of these problems while working on www.chatterblock.com (which you should check it out).

If you have used or heard of Django's flatpages app before, you'll be more able to appreciate what django-simple-templates gives you. It is inspired by flatpages, with a desire to have fewer knowledge dependencies and greater flexibility.

Note that this is a work in progress - please provide feedback!

Objectives

django-simple-templates is intended to:

• provide the means to isolate template designer effort; reduce web developer involvement
• provide an easy way to launch flat or simple pages quickly; no URL pattern or view needed
• provide a quick and simple method to do A/B testing (split testing) with Django templates

Use Cases

If you need to quickly launch landing pages for marketing campaigns, then django-simple-templates is for you.

If you have a great web designer who knows next to nothing about Django, then django-simple-templates is likely a good fit. It helps to reduce the need for:

• training web designers on Django URL patterns, views, etc. - you can restrict the necessary knowledge to Django templates and template tags (custom and/or builtin)
• involving web developers to create stub page templates or to convert designer-created static HTML pages to Django templates

If you want to be able to A/B test any Django template with an external service such as GACE (Google Analytics Content Experiments), then django-simple-templates will absolutely help you. I've always found A/B testing with Django (and frameworks in general) to be somewhat painful - hopefully this app alleviates that pain for others too.

Installation

It's a standard PyPi install:

pip install django-simple-templates

To use the simple page template functionality, add the SimplePageFallbackMiddleware to your MIDDLEWARE_CLASSES in your settings.py:

MIDDLEWARE_CLASSES = (
    ... # other middleware here
    'simple_templates.middleware.SimplePageFallbackMiddleware'
)

Note that this middleware is not necessary if you only want to use the get_ab_template functionality (see below).

Configuration Options

django-simple-templates has a few options to help cater to your project's needs. You can override these by setting them in your settings.py. Each has an acceptable default value, so you do not need to set them:

• SIMPLE_TEMPLATES_AB_PARAM: optional; defaults to ab. This is the query string (request.GET) parameter that contains the name of the A/B testing template name.
• SIMPLE_TEMPLATES_AB_DIR: optional; defaults to ab_templates. This is the subdirectory inside your TEMPLATE_DIRS where you should place your A/B testing page templates.
• SIMPLE_TEMPLATES_DIR: optional; defaults to simple_templates. This is the subdirectory inside your TEMPLATE_DIRS where you should place your simple page templates.

Usage

To create a "simple template" page, all you need to do is create a template file under SIMPLE_TEMPLATES_DIR. This is your standard Django template format, inheritance, etc. The directory structure you place it in determines the URL structure. For example, creating a template here:

<your_templates_dir>/simple_templates/en/contact.html

would result in the a URL structure like:

http://www.example.com/en/contact/

The SimplePageFallbackMiddleware middleware kicks in and looks for possible template file matches when an Http404 is the response to a web request, so if you had a URL pattern and view that handled the /en/contact/ URL, this middleware would not do anything at all.

To create an A/B testing template (the variation template) for the example simple page template above, you'd create the variation template under the appropriate directory structure under SIMPLE_TEMPLATES_AB_DIR:

<your_templates_dir>/ab_templates/simple_templates/en/contact/variation1.html

and the resulting URL would be:

http://www.example.com/en/contact/?ab=variation1

So you can see that the A/B testing variation template needs to exist in a directory structure mimicking the original template's directory structure plus its filename without extension.

Special case: If you want to create simple page template for the root 'home' page of your website, you given the simple template a special name of _homepage_.html. URL and directory example:

<your_templates_dir>/simple_templates/_homepage_.html

would be accessible at:

http://www.example.com/

If you wanted to create an A/B testing variation template on this page, the simple variation template would exist here:

<your_templates_dir>/ab_templates/simple_templates/_homepage_/variation2.html

and you'd access it like the examples above:

http://www.example.com/?ab=variation2

Using A/B Testing in Django Views

To use the A/B testing functionality in your existing code, import get_ab_template and use it in your view:

from django.shortcuts import render
from simple_templates.utils import get_ab_template

def user_signup(request):
    template = get_ab_template(request, 'profiles/user/signup.html')
    return render(request, template)

The get_ab_template function works like this:

• pass Django's request object and the view's normal template into get_ab_template
• the get_ab_template will look in request.GET to see if there was an ab parameter in the query string
• if ab is found in request.GET, get_ab_template will attempt to find the associated template file under SIMPLE_TEMPLATES_AB_DIR
• if the ab template file is found, the ab template path is returned
• if either ab or the template file associated with ab is not found, the passed-in 'default' template file is returned

Here's an example to demonstrate. If you want to A/B test your signup page with the URL:

http://www.example.com/user/signup/

and your current user signup template file located here:

<your_templates_dir>/profiles/user/signup.html

with a variation called 'fewer-inputs', you would first modify your Django view for a user signing up to use get_ab_template and you would have this URL as your variation page:

http://www.example.com/user/signup/?ab=fewer-inputs

and your variation template file should be placed here:

<your_templates_dir>/ab_templates/profiles/user/signup/fewer-inputs.html

Tips for Optimising your Implementation

SEO Considerations

Speaking plainly, you need to watch that you don't create duplicate content in the eyes of search engines. What's duplicate content? Two pages that are (almost) identical. When you're doing A/B testing, you're frequently doing minor variations on a theme - perhaps only the colour of a single button.

Canonical link elements to the rescue. These are simply an HTML element you place in your <head> section of your variation template pages, like so:

<html>
<head>
    <title>My variation webpage</title>
    <link rel="canonical" href="<< whatever your original page URL is >>">
</head>
<body>
    ...
</body>
</html>

The link represented by << whatever your original page URL is >> in the above example should point to the 'canonical' page URL (without the 'ab=variation-name' parameter); meaning the original page URL that you want indexed by search engines. This way, any search engine that sees a variation template page will 'ignore' it because you're telling it to see it the same as the original page. But you can make this a lot easier on yourself, by using the excellent django-spurl app, and making it this change in your base.html, like so:

<html>
<head>
    <title>base.html template</title>
    <link rel="canonical" href="{% block head-canonical %}{% spurl base=request.get_full_path remove_query_param='ab' %}{% endblock %}">
</head>
<body>
    ...
</body>
</html>

and then extend all of your templates (normal view templates, simple templates and A/B templates) from this base.html. The spurl template tag simply removes the ab parameter to create the canonical link for you on every single page on your site, making split testing easy, one less thing to think about. Note that you'll need to add the django.core.context_processors.request to your TEMPLATE_CONTEXT_PROCESSORS in settings.py and install django-spurl for this to work.

Google Analytics Content Experiments Integration (GACE)

Based on the example above, easy integration for GACE follows a similar strategy - have a <head> block in your base.html where you can override to place the GACE Javascript snippet, like so:

<html>
<head>
    {% block head-gace-js %}{% endblock %}
    <title>base.html template</title>
    <link rel="canonical" href="{% block head-canonical %}{% spurl base=request.get_full_path remove_query_param='ab' %}{% endblock %}">
</head>
<body>
    ...
</body>
</html>

Then, in any 'original' page that you want to do an A/B test on, you'd override the head-gace-js block to paste in the GACE JS snippet:

{% extends 'base.html' %}

{# You would only do this in the original template, not the variation templates! See GACE help for more details. #}
{% block head-gace-js %}
... GACE JS code snippet here
{% endblock %}

... original page's block overrides for content, etc.

I've done a limited amount of testing on the GACE integration, so please report your results!

Running Unit Tests

To run the django-simple-templates tests, follow these steps:

• clone the django-simple-templates repository
• change directory into the repository
• initialize a 'virtualenv': virtualenv --distribute .
• activate the virtualenv: source bin/activate
• install the dependencies for testing django-simple-templates: pip install -r test_project/test-requirements.txt
• run the tests: python test_project/manage.py test simple_templates

Tests have been run under:

• Python 2.7.3 and Django 1.4.3
• (please report other results)

Compatibility

django-simple-templates been used in the following version configurations:

• Python 2.6, 2.7
• Django 1.4, 1.5, 1.6, 1.7, 1.9

It should work with prior versions; please report your usage and submit pull requests as necessary.

Source

The latest source code can always be found here: http://github.com/jaddison/django-simple-templates/

Credits

django-simple-templates is maintained by James Addison, code@scottisheyes.com.

License

django-simple-templates is Copyright (c) 2013, James Addison. It is free software, and may be redistributed under the terms specified in the LICENSE file.

Questions, Comments, Concerns:

Feel free to open an issue here: http://github.com/jaddison/django-simple-templates/issues/ - or better yet, submit a pull request with fixes and improvements.