Question

Writing template tags isn’t easy in Django and involves lots of boilerplate code.
What is the least painful way to do it?

• Are there any libs for that?
• Are there any tricks that doesn’t involve third-party apps?
• What is your way to do it?

(I will make this post a community wiki once I figure how to do it.)

Answer 1

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There are some libs for that:

• django-templatetag-sugar

  Used it before. Makes everythings simpler, but I couldn’t figure how to handle lots of optional arguments with it.

  Usage example::

  ''' {% example_tag for val as asvar %} '''
  
  @tag(register, [
      Constant("for"), Variable(),
      Optional([Constant("as"), Name()]),
      ])
  def example_tag(context, val, asvar=None):
      if asvar:
          context[asvar] = val
          return ""
      else:
          return val
  

• django-tagcon, abandoned by original author

• django-ttag, fork of django-tagcon

  These two look promising because of class-based approach and keyword arguments support (like {% output limit=some_limit|default:1 offset=profile.offset %})

  Example usage::

  class Welcome(ttag.Tag):
      ''' {% welcome current_user fallback "Hello, anonymous." %} '''
      user = ttag.Arg(positional=True)
      fallback = ttag.Arg(default='Hi!')
  
      def output(self, data)
          name = data['user'].get_full_name()
          if name:
              return 'Hi, %s!' % name
          return data['fallback']
  

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