django-jstemplate

A templatetag framework for easier integration of mustache.js, dust.js, handlebars.js, or other JavaScript templates with Django templates. Also will wrap your templates in elements expected for libraries such as ICanHaz.js. Django-jstemplates is extensible, so if your favorite template library is not included, it’s easy to add. Inspired by django-icanhaz.

Quickstart

Dependencies

Tested with Django 1.5 through trunk, and Python 2.6, 2.7, and 3.3. Almost certainly works with older versions of both.

Installation

Install from PyPI with pip:

pip install django-jstemplate

or get the in-development version:

pip install django-jstemplate==dev

Usage

  • Add "jstemplate" to your INSTALLED_APPS setting.

  • In your HTML header, include the Javascript templating library of your choice (I like to use mustache.js):

    wget https://raw.github.com/janl/mustache.js/master/mustache.js
    mv mustache.js app/static/libs/
  • {% load jstemplate %} and use {% mustachejs "templatename" %} in your Django templates to safely embed the mustache.js template at <JSTEMPLATE_DIRS-entry>/templatename.html into your Django template. It will be stored in the Mustache.TEMPLATES object as a string, accessible as Mustache.TEMPLATES.templatename.

  • In your JavaScript, use Mustache.to_html(Mustache.TEMPLATES.templatename, {...}, Mustache.TEMPLATES) to render your mustache template. Alternatively, if you include the libs/django.mustache.js script in your HTML, you can use Mustache.template('templatename').render({...}) to render your mustache template.

An Example

For example consider the files app/jstemplates/main.mustache:

<div>
  <p>This is {{ name }}'s template</p>
</div>

and app/templates/main.html:

{% load jstemplate %}

<html>
<head>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.js"></script>

  <script src="{{ STATIC_URL }}libs/mustache.js"></script>
  <script src="{{ STATIC_URL }}libs/django.mustache.js"></script>
</head>

<body>
  <div id="dynamic-area"></div>

  {% mustachejs "main" %}

  <script>
    $(document).ready(function() {

      var $area = $('#dynamic-area')
        , template;

      // Either render by accessing the TEMPLATES object
      // directly...

      $area.html(Mustache.to_html(Mustache.TEMPLATES.main));

      // ...or render by using a cached template object
      // (requires django.mustache.js)

      template = Mustache.template('main');
      $area.html(template.render());

    });
  </script>
</body>
</html>

Handlebars.js

The handlebarsjs template tag has two optional parameters.

  • precompile will add your templates to a templates attribute on the Handlebars object. For example:

    {% handlebarsjs 'my-template' precompile %}
    
    <script>
      var html = Handlebars.templates['my-template']();
    </script>
  • register_partial will make your templates available as partials to use in other templates. For example, take the following templates:

my-template.html:

<p>This is a list</p>
<ul>
  {{# each people }}
  {{> my-partial }}
  {{/ each }}
</ul>

my-partial.html:

<li>{{ name }}</li>

index.html:

...
{% handlebarsjs 'my-template' %}
{% handlebarsjs 'my-partial' register_partials %}
...

What’s going on?

Any time you use the mustachejs template tag, or any of the other jstemplate tags:

{% load jstemplate %}
{% mustachejs "main" %}

django-jstemplate will generate something like the following:

<script>Mustache.TEMPLATES=Mustache.TEMPLATES||{};Mustache.TEMPLATES['main']='<div>\n  <p>This is {{ name }}\'s template</p>\n</div>';</script>

This stores the text of the template in an attribute on the Mustache.TEMPLATES object (it will first create the object if it does not yet exist). The Mustache.template(...) function then creates an object with a render(...) method that has a similar signature as Mustache.to_html(...), except without the template name as the first parameter. The render method will also use the set of templates in Mustache.TEMPLATES as partials, allowing any template that django-mustachejs knows about to be used as a template partial as well.

Other tags, just as {% icanhazjs %} wrap your template in the elements expected for particular libraries (like for ICanHaz.js in that situation).

Flavors of Javascript templates

In addition to {% mustachejs ... %}, django-jstemplate comes with several template tags that you can use to render your mustache templates:

  • {% dustjs ... %} renders templates ready for consumption by dust.js
  • {% icanhazjs ... %} renders templates ready for consumption by ICanHaz.js
  • {% handlebarsjs ... %} renders templates ready for consumption by Handlebars.js
  • {% rawjstemplate ... %} renders the raw contents of a mustache template, after preprocessing

Matching Multiple Template Files

The name provided to the template tag can be a string that will match a single file, a file glob pattern, or a regular expression. Using the template tag {% mustachejs [glob/regex] %} in your Django templates will embed all files matching that regex in the template directories. So, {% mustachejs '(.*_template)' %} and {% mustachejs '*_template' %} would both match note_template.html and comment_template.html, giving them templatename note_template and comment_template, respectively. (Note that the regular expression pattern must contain parentheses denoting a single matching group; this group will become the name of the template).

Internationalization (i18n)

django-mustachejs supports internationalization tags. In your settings module, set the JSTEMPLATE_I18N_TAGS variables (default: ('_', 'i18n')). These tags can be used to preprocess the javascript templates into translatable content. For example:

<div>{{#_}}Hello, {{name}}.  I like your {{color}} {{thing}}?{{/_}}</div>

may render to:

<div>Salut, {{name}}.  J'aime votre {{thing}} {{color}}?</div>

The translatable strings will be picked up by Django’s makemessages management command.

Under the hood

In order to avoid having to send our project’s translation mapping to the client, we have built-in the ability to preprocess i18n tags in the mustache templates.

There aren’t any nice solutions here. The code behind makemessages unfortunately isn’t extensible, so we can:

  • Duplicate the command + code behind it.
  • Offer a separate command for Mustache tag extraction.
  • Try to get Django to offer hooks into makemessages.
  • Monkey-patch.

We are currently doing that last thing. In this case we override the templatize method. templatize takes a template, extracts the translatable strings (along with desired metadata), and generates a file that xgettext knows how to parse, e.g. a file with Python syntax. We override this function to find Mustache-tagged strings if the file that we are templatizing is in one of the paths found by the active JSTEMPLATE_FINDERS.

Settings

  • Set JSTEMPLATE_FINDERS to configure the dotted class names of the finders the application will use. By default, this is the following list:

    ["jstemplate.finders.FilesystemFinder",
     "jstemplate.finders.AppFinder",
     "jstemplate.finders.FilesystemRegexFinder",
     "jstemplate.finders.AppRegexFinder",]
    
  • Set the JSTEMPLATE_DIRS setting to a list of full (absolute) path to directories where you will store your mustache templates. By default this is an empty list.

  • Set JSTEMPLATE_APP_DIRNAMES to a list of directory names that can be found under directories of applications specified in INSTALLED_APPS. By default, this setting has the value of ["jstemplates"].

  • Set the JSTEMPLATE_EXTS setting to a list of the app should search for to find template files. By default this is set to ['mustache', 'html']. Order matters (e.g., *.mustache will take precedence over *.html).

  • Set the JSTEMPLATE_PREPROCESSORS variable to control how the templates are preprocessed. By default, there is one preprocessor activated:

    ['jstemplate.preprocessors.I18nPreprocessor']
    

    The I18nPreprocessor will translate marked strings before rendering the template. To disable this feature, set JSTEMPLATE_PREPROCESSORS to an empty list.

  • Set JSTEMPLATE_I18N_TAGS to the names of the tags used to mark strings for internationalization. By default, this is set to the list:

    ["_", "i18n"]
    

    Meaning that text falling between the tags {{#_}}...{{/_}} and {{#i18n}}...{{/i18n}} will be marked for translation.

Advanced usage

Custom Finders

The finding of templates can be fully controlled via the JSTEMPLATE_FINDERS setting, which is a list of dotted paths to finder classes. A finder class should be instantiable with no arguments, and have a find(name) method which returns either (1) the full absolute path to a template file, given a base-name, or (2) a list of (template name, template file path) pairs according to the given base name.

By default, JSTEMPLATE_FINDERS contains "jstemplate.finders.FilesystemFinder" (which searches directories listed in JSTEMPLATE_DIRS), "jstemplate.finders.AppFinder" (which searches subdirectories named in JSTEMPLATE_APP_DIRNAMES of each app in INSTALLED_APPS), "jstemplate.finders.FilesystemRegexFinder", and "jstemplate.finders.AppRegexFinder", in that order – thus templates found in JSTEMPLATE_DIRS take precedence over templates in apps, and templates identified by file glob patterns take precedence over those identified by regular expression patterns.

Custom Preprocessors

Before your JavaScript templates are placed into your Django templates, they are run through preprocessors. By default, the only preprocessor enabled is for internationalization (i18n). The i18n preprocessor finds all text between {{#_}} and {{/_}}, translates it with gettext, and inserts the translated text into the template, stripping the {{#_}} and {{/_}} tags.

You can build your own preprocessors as well. A good use would be to do things like including generated URLs in your templates. For example, in your template, when you have {{reverse_url 'my_url_name'}}, you might want to run that through Django’s reverse method.

A preprocessor class is pretty simple. All it requires is a method with the following signature:

def process(self, content):
    ...

Where content is the actual text of the JS template. Then, just add the dotted name of your class ot the JSTEMPLATE_PREPROCESSORS settings variable.

Custom Flavors

It is simple to extend django-jstemplate to prepare your JavaScript templates to be used with your favorite Javascript library by creating a template node class that derives from jstemplate.templatetags.BaseJSTemplateNode, and overriding a single function. Refer to the existing tag definitions for mustachejs, icanhazjs, rawjstemplate, and handlebarsjs for more information.

Source

The source for django-jstemplate is available on GitHub

Running tests

To run the tests (for development), install mock and six and run:

jstemplate/tests/project/manage.py test