Making Templatetags Suck Less
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The document proposes a Python library called django-templatetag-sugar that aims to simplify the process of defining template tags in Django. It allows template tags to be defined by writing a regular Python function and decorating it, rather than requiring boilerplate parsing code. This avoids 45 lines of code needed for parsing and reduces the badge count example to just 6 lines of code. The library handles argument parsing and variable resolution automatically in the template context.
![class BadgeCountNode(template.Node):
@classmethod
def handle_token(cls, parser, token):
bits = token.split_contents()
if len(bits) == 2:
return cls(bits[1])
elif len(bits) == 4:
if bits[2] != "as":
raise template.TemplateSyntaxError("Second argument to %r must "
"be 'as'" % bits[0])
return cls(bits[1], bits[3])
raise template.TemplateSyntaxError("%r takes either 1 or 3 arguments." % bits[0])
def __init__(self, user, context_var=None):
self.user = template.Variable(user)
self.context_var = context_var
def render(self, context):
user = self.user.resolve(context)
badge_count = BadgeAward.objects.filter(user=user).count()
if self.context_var is not None:
context[self.context_var] = badge_count
return ""
return unicode(badge_count)
@register.tag
def badge_count(parser, token):
"""
Returns badge count for a user, valid usage is::
{% badge_count user %}
or
{% badge_count user as badges %}
"""
return BadgeCountNode.handle_token(parser, token)](https://image.slidesharecdn.com/templatetag-sugar-100524095015-phpapp01/85/Making-Templatetags-Suck-Less-2-320.jpg)
![@tag(register, [Variable(), Optional([Constant("as"), Name()]))
def badge_count(context, user, varname=None):
badge_count = BadgeAward.objects.filter(user=user).count()
if varname is not None:
context[varname] = badge_count
return ""
return unicode(badge_count)
All Done](https://image.slidesharecdn.com/templatetag-sugar-100524095015-phpapp01/85/Making-Templatetags-Suck-Less-6-320.jpg)
Making Templatetags Suck Less
- 1. Making TemplateTags Suck Less
- 2. class BadgeCountNode(template.Node): @classmethod def handle_token(cls, parser, token): bits = token.split_contents() if len(bits) == 2: return cls(bits[1]) elif len(bits) == 4: if bits[2] != "as": raise template.TemplateSyntaxError("Second argument to %r must " "be 'as'" % bits[0]) return cls(bits[1], bits[3]) raise template.TemplateSyntaxError("%r takes either 1 or 3 arguments." % bits[0]) def __init__(self, user, context_var=None): self.user = template.Variable(user) self.context_var = context_var def render(self, context): user = self.user.resolve(context) badge_count = BadgeAward.objects.filter(user=user).count() if self.context_var is not None: context[self.context_var] = badge_count return "" return unicode(badge_count) @register.tag def badge_count(parser, token): """ Returns badge count for a user, valid usage is:: {% badge_count user %} or {% badge_count user as badges %} """ return BadgeCountNode.handle_token(parser, token)
- 3. WTF is all that crap 50% boilerplate 45 LOC for 4 lines of logic Hacking parsing
- 4. There’s gotta be a better way A syntax to define argument parsing, how to parse them, and what types to interpret them as. Automatic variable resolution in the context, and conversion to correct types.
- 5. django-templatetag- sugar Define your templatetags’ syntax in a Pythonic way write a function and decorate
- 6. @tag(register, [Variable(), Optional([Constant("as"), Name()])) def badge_count(context, user, varname=None): badge_count = BadgeAward.objects.filter(user=user).count() if varname is not None: context[varname] = badge_count return "" return unicode(badge_count) All Done
- 7. 6 LOC This feels like cheating...