Added ability to set a custom subject match method for the rule subject matcher

bouncer/__init__.py

@@ -54,6 +54,13 @@ def get_authorization_method():
 
 _authorization_target = None
 
+def custom_subject_matcher(original_method):
+    """The method which extends the usual subject matching process of a subject"""
+    Rule._custom_subject_matcher = original_method
+    return original_method
+
+def get_custom_subject_matcher():
+    return Rule._custom_subject_matcher
 
 def authorization_target(original_class):
     """ Add bouncer goodness to the model.  This is a class decorator, when added to your User model if will add
@@ -71,4 +78,4 @@ def cannot(self, action, subject):
     setattr(original_class, 'can', can)
     setattr(original_class, 'cannot', cannot)
 
-    return original_class
+    return original_class

bouncer/models.py

@@ -18,6 +18,9 @@ def listify(list_or_single):
 
 
 class Rule(object):
+
+    _custom_subject_matcher = None
+
     def __init__(self, base_behavior, action, subject, conditions=None, **conditions_hash):
         self.base_behavior = base_behavior
         self.actions = listify(action)
@@ -92,6 +95,10 @@ def matches_subject_class(self, subject):
                     return subject.__name__ == sub
                 else:
                     return subject.__class__.__name__ == sub
+
+        if callable(Rule._custom_subject_matcher):
+            return Rule._custom_subject_matcher(self, subject)
+
         return False
 
 

bouncer/test_bouncer/__init__.py

@@ -1,6 +1,6 @@
 import nose
 from nose.tools import assert_raises, raises
-from bouncer import authorization_target, authorization_method, Ability, can, cannot, ensure
+from bouncer import authorization_target, authorization_method, custom_subject_matcher, Ability, can, cannot, ensure
 from bouncer.exceptions import AccessDenied
 from bouncer.constants import *
 from models import User, Article, BlogPost
@@ -168,7 +168,6 @@ def if_author(article):
     assert relevant_rules[0].actions == [EDIT]
     assert relevant_rules[0].subjects == [Article]
 
-
 def test_using_class_strings():
 
     @authorization_method
@@ -188,6 +187,31 @@ def authorize(user, they):
     assert sally.can(EDIT, article)
 
 
+def test_using_custom_subject_function():
+
+    class TestAuth:
+        name = 'Test'
+
+    try:
+        @custom_subject_matcher
+        def subject_match(rule, subject):
+            for subject in rule.subjects:
+                if subject == TestAuth.name:
+                    return True
+            return False
+
+        @authorization_method
+        def authorize(user, they):
+            they.can(READ, 'Test')
+
+        article = Article()
+        sally = User(name='sally', admin=False)
+
+        assert sally.can(READ, article)
+
+    finally:
+        custom_subject_matcher(None)
+
 def test_cannot_override():
 
     @authorization_method
@@ -214,4 +238,4 @@ def authorize(user, they):
 
 
 if __name__ == "__main__":
-    nose.run()
+    nose.run()