Merge pull request #4 from petahz/dicts-and-sets-args-order

Dicts and sets args order

Author: petahz

.travis.yml

@@ -1,16 +1,14 @@
 language: python
 python:
-    - 2.7
     - 3.4
 env:
-    - DJANGO_VERSION=1.5.12
-    - DJANGO_VERSION=1.6.10
-    - DJANGO_VERSION=1.7.7
+    - DJANGO_VERSION=1.8.17
 install:
     # Install django/nose
     - pip install Django==$DJANGO_VERSION
     - pip install django-nose
     # Install cache helper
     - pip install -e .
+    - pip install pylibmc
 script:
     - python test_project/manage.py test

cache_helper/utils.py

@@ -120,11 +120,31 @@ def _plumb_collections(input_item):
             # this if statement. That's why we do `not isinstance(current_item, str)` check as well.
             if hasattr(current_item, '__iter__') and not isinstance(current_item, str):
                 return_list.append(',')
+
+                # Dictionaries and sets are unordered and can be of various data types
+                # We use the sha256 hash on keys and sort to be deterministic
                 if isinstance(current_item, dict):
+                    hashed_list = []
+
+                    for k, v in current_item.items():
+                        hashed_list.append((sha256(str(k).encode('utf-8')).hexdigest(), v))
+
+                    hashed_list = sorted(hashed_list, key=lambda t: t[0])
                     remains.append(current_iterator)
-                    remains.append([(k,v) for k, v in current_item.items()].__iter__())
+                    remains.append(hashed_list.__iter__())
+
                     level -= 1
                     break
+                elif isinstance(current_item, set):
+                    hashed_list = []
+
+                    for item in current_item:
+                        hashed_list.append(sha256(str(item).encode('utf-8')).hexdigest())
+
+                    hashed_list = sorted(hashed_list)
+                    remains.append(current_iterator)
+                    remains.append(hashed_list.__iter__())
+                    break
                 else:
                     remains.append(current_iterator)
                     remains.append(current_item.__iter__())

test_project/tests.py

@@ -123,8 +123,10 @@ def test_keys_are_truncated_beyond_250_chars(self):
         except Exception:
             self.fail('Keys are not being correctly truncated.')
 
+from hashlib import sha256
 
 class KeyCreationTestCase(TestCase):
+
     def setUp(self):
         self.apple = Fruit('Apple')
         self.cherry = Fruit('Cherry')
@@ -141,7 +143,23 @@ def test_args_kwargs_properly_convert_to_string(self):
 
     def test_dict_args_properly_convert_to_string(self):
         same_cherry = self.apple.take_then_give_back({1: self.cherry})
-        self.assertTrue('tests.Fruit.take_then_give_back:42;mynameisapple,,,1,mynameischerry;' in cache)
+        hashed_key = sha256(str(1).encode('utf-8')).hexdigest()
+        self.assertTrue('tests.Fruit.take_then_give_back:42;mynameisapple,,,{0},mynameischerry;'.format(hashed_key) in cache)
+
+    def test_dict_args_keep_the_same_order_when_convert_to_string(self):
+        dict_arg = {1: self.cherry, 'string': 'ay carambe'}
+        same_multi_dict = self.apple.take_then_give_back(dict_arg)
+
+        self.assertTrue('tests.Fruit.take_then_give_back:42;mynameisapple,,,'
+                        '473287f8298dba7163a897908958f7c0eae733e25d2e027992ea2edc9bed2fa8,aycarambe,,'
+                        '6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b,mynameischerry;' in cache)
+
+    def test_set_args_properly_maintain_order_and_convert_to_string(self):
+        same_set = self.apple.take_then_give_back({1,'vegetable', self.cherry})
+        self.assertTrue('tests.Fruit.take_then_give_back:42;mynameisapple,,'
+                        '4715b734085d8d9c9981d91c6d5cff398c75caf44074851baa94f2de24fba4d7,'
+                        '6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b,'
+                        'f8201a5264b6b89b4d92c5bc46aa2e5c3e9610e8fc9ef200df1a39c7f10e7af6;' in cache)
 
     def test_list_args_properly_convert_to_string(self):
         same_cherry = self.apple.take_then_give_back([self.cherry])