Django+装饰:根据条件向模板添加上下文

我将使用自定义模板标记。它使得设置上下文变量非常容易

#yourapp/templatetags/business_tags.py

from django import template
register = template.Library()

class BusinessNode(template.Node):
  def __init__(self, instance, varName):
    self.instance, self.varName=instance, varName

  def render(self, context):
    instance=template.Variable(self.instance).render(context)
    if instance.passes_some_test():
      context[self.varName]='Some message'
    else:
      context[self.varName]="Some other message"
    return ''
@register.tag
def business_check(parser, token):
  bits=token.split_contents()
  if len(bits)==5:
    return BusinessNode(bits[2],bits[4])
  return ''

然后在模板中

{% load business_tags %}

{% business_check for someVar as myMessage %}
{{myMessage}}

这对于将其他类型的数据插入到上下文中同样有效。