django-logical-rules 1.0

Template Tag

Once you have created a rule, it’s easy to use anywhere in your templates:

{% load logical_rules_tags %}
{% testrule user_can_edit_mymodel object request.user %}
        <p>You are the owner!</p>
{% endtestrule %}

Note: Don’t use quotes around the rule name in the template.

RulesMixin

If you are extending Django’s class-based generic views, you might find this mixin useful. It allows you to define rules that should be applied before rendering a view. Here’s an example usage:

class MyView(RulesMixin, DetailView):

   def update_logical_rules(self):
      super(MyView, self).update_logical_rules()
      self.add_logical_rule({
         'name': 'user_can_edit_mymodel',
         'param_callbacks': [
            ('object', 'get_object'),
            ('user', 'get_request_user')
         ]
      })

param_callbacks are our technique for getting the parameters for your rule. These are assumed to be methods on your class. get_request_user() is defined in RuleMixin since it’s so common. get_object() is a method on the DetailView class.

Rule dictionaries can have other properties, like redirect_url and response_callback. If redirect_url is defined, then the view will return an HttpResponseRedirect to that URL. If response_callback is defined, then the view will return the result of that method.

Messaging integration is possible with message and message_level options.

Finally, we’ve added two commonly used rules. As an optional substitute for login_required, we have user_is_authenticated and to test a generic expression, we have evaluate_expression.

Direct Calling

import logical_rules
if logical_rules.site.test_rule(rule['name'], arg1, arg2):
        print "passed"
else:
        print "failed"