Add support for special method get_cache_key on objects

tests/cache/test_util.py

@@ -0,0 +1,66 @@
+# coding: utf-8
+from torneira.cache.util import cache_key, cached
+
+from tests.util import unittest
+
+
+class MySimpleObject(object):
+    @cached
+    def do_something(self, a, b):
+        return a + b
+
+
+class MyModel(object):
+    id = None
+
+    def __init__(self, id_):
+        self.id = id_
+
+    @cached
+    def do_something(self, a, b):
+        return a + b
+
+
+class ObjectWithSpecialMethod(object):
+    # just to ensure that cache_key will not use this value
+    id = 'should-not-be-used'
+    _my_value = None
+
+    def __init__(self, value):
+        self._my_value = value
+
+    def get_cache_key(self):
+        return self._my_value
+
+    @cached
+    def do_something(a, b):
+        return a + b
+
+
+class GenerateCacheKeyTestCase(unittest.TestCase):
+    def test_generate_cache_key_for_simple_object(self):
+        my_instance = MySimpleObject()
+
+        fn_kwargs = {'a': 1, 'b': 2}
+        _, generated_key = cache_key(my_instance, 'do_something', **fn_kwargs)
+        expected_key = 'tests.cache.test_extension.MySimpleObject().do_something(a=1,b=2)'
+
+        self.assertEqual(generated_key, expected_key)
+
+    def test_generate_cache_key_for_model_object(self):
+        my_instance = MyModel("unique-id-1")
+
+        fn_kwargs = {'a': 1, 'b': 2}
+        _, generated_key = cache_key(my_instance, 'do_something', **fn_kwargs)
+        expected_key = 'tests.cache.test_extension.MyModel(unique-id-1).do_something(a=1,b=2)'
+
+        self.assertEqual(generated_key, expected_key)
+
+    def test_generate_cache_key_for_object_with_special_method(self):
+        my_instance = ObjectWithSpecialMethod('unique-value')
+
+        fn_kwargs = {'a': 1, 'b': 2}
+        _, generated_key = cache_key(my_instance, 'do_something', **fn_kwargs)
+        expected_key = 'tests.cache.test_extension.ObjectWithSpecialMethod(unique-value).do_something(a=1,b=2)'
+
+        self.assertEqual(generated_key, expected_key)

torneira/cache/util.py

@@ -46,7 +46,9 @@ def cache_key(instance, method, **kwarguments):
     cachekey = cachekey.replace("{classe}", instance.__class__.__name__)
     cachekey = cachekey.replace("{method}", method)
 
-    if hasattr(instance, "id") and instance.id:
+    if hasattr(instance, "get_cache_key"):
+        cachekey = cachekey.replace("{instanceid}", str(instance.get_cache_key()))
+    elif hasattr(instance, "id") and instance.id:
         cachekey = cachekey.replace("{instanceid}", "%s" % instance.id)
     else:
         cachekey = cachekey.replace("{instanceid}", "")