Making Templatetags Suck Less

Making TemplateTags Suck Less

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)

WTF is all that crap 50% boilerplate 45 LOC for 4 lines of logic Hacking parsing

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.

django-templatetag- sugar Deﬁne your templatetags’ syntax in a Pythonic way write a function and decorate

@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

6 LOC This feels like cheating...

http://github.com/alex/django-templatetag- sugar http://alexgaynor.net/ Slides will be on my blog.

Making Templatetags Suck Less

by Alex Gaynor on May 24, 2010

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Making Templatetags Suck Less — Presentation Transcript

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