allow to pass a value to get_or_set

fixes issue sebleier#124

Author: PoByBolek

docs/api.rst

@@ -131,16 +131,18 @@ Cache Methods Provided by django-redis-cache
     :param version: Version of the keys
 
 
-.. function:: get_or_set(self, key, func[, timeout=None, lock_timeout=None, stale_cache_timeout=None]):
+.. function:: get_or_set(self, key, default[, timeout=None, lock_timeout=None, stale_cache_timeout=None]):
 
-    Get a value from the cache or call ``func`` to set it and return it.
+    Get a value from the cache or use ``default`` to set it and return it.
+
+    If ``default`` is a callable, call it without arguments and store its return value in the cache instead.
 
     This implementation is slightly more advanced that Django's.  It provides thundering herd
     protection, which prevents multiple threads/processes from calling the value-generating
     function at the same time.
 
     :param key: Location of the value
-    :param func: Callable used to set the value if key does not exist.
+    :param default: Used to set the value if key does not exist.
     :param timeout: Time in seconds that value at key is considered fresh.
     :type timeout: Number of seconds or None
     :param lock_timeout: Time in seconds that the lock will stay active and prevent other threads from acquiring the lock.

redis_cache/backends/base.py

@@ -410,11 +410,13 @@ def get_or_set(
             self,
             client,
             key,
-            func,
+            default,
             timeout=DEFAULT_TIMEOUT,
             lock_timeout=None,
             stale_cache_timeout=None):
-        """Get a value from the cache or call ``func`` to set it and return it.
+        """Get a value from the cache or use ``default`` to set it and return it.
+
+        If ``default`` is a callable, call it without arguments and store its return value in the cache instead.
 
         This implementation is slightly more advanced that Django's.  It provides thundering herd
         protection, which prevents multiple threads/processes from calling the value-generating
@@ -429,9 +431,6 @@ def get_or_set(
             expired. If ``None`` is specified, the stale value will remain indefinitely.
 
         """
-        if not callable(func):
-            raise Exception("Must pass in a callable")
-
         lock_key = "__lock__" + key
         fresh_key = "__fresh__" + key
 
@@ -448,7 +447,7 @@ def get_or_set(
 
         if acquired:
             try:
-                value = func()
+                value = default() if callable(default) else default
             except Exception:
                 raise
             else:

redis_cache/backends/dummy.py

@@ -8,11 +8,8 @@ def ttl(self, key):
     def delete_pattern(self, pattern, version=None):
         return None
 
-    def get_or_set(self, key, func, timeout=None):
-        if not callable(func):
-            raise Exception("Must pass in a callable")
-
-        return func()
+    def get_or_set(self, key, default, timeout=None):
+        return default() if callable(default) else default
 
     def reinsert_keys(self):
         return None

tests/testapp/tests/base_tests.py

@@ -486,7 +486,7 @@ def test_ttl_of_reinsert_keys(self):
         self.assertEqual(self.cache.get('b'), 'b')
         self.assertGreater(self.cache.ttl('a'), 1)
 
-    def test_get_or_set(self):
+    def test_get_or_set_with_callable(self):
 
         def expensive_function():
             expensive_function.num_calls += 1
@@ -511,6 +511,15 @@ def expensive_function():
         self.assertEqual(expensive_function.num_calls, 2)
         self.assertEqual(value, 42)
 
+    def test_get_or_set_with_value(self):
+        self.assertEqual(self.cache.get_or_set('a', 42, 1), 42)
+        self.assertEqual(self.cache.get_or_set('a', 43, 1), 42)
+        self.assertEqual(self.cache.get_or_set('a', 44, 1), 42)
+        time.sleep(2)
+        self.assertEqual(self.cache.get_or_set('a', 45, 1), 45)
+        self.assertEqual(self.cache.get_or_set('a', 46, 1), 45)
+        self.assertEqual(self.cache.get_or_set('a', 47, 1), 45)
+
     def test_get_or_set_serving_from_stale_value(self):
 
         def expensive_function(x):