Add a strict boolean parameter to FlaskRedis initializer

The parameter allows easily choosing between using redis.StrictRedis or
redis.Redis as the client.

Closes #15

Author: underyx

flask_redis.py

@@ -1,18 +1,22 @@
 import warnings
-from redis import Redis as _Redis
+try:
+    import redis
+except ImportError:
+    # We can allow custom provider only usage without redis-py being installed
+    redis = None
 
 __all__ = ('Redis', 'FlaskRedis')
 __version__ = '0.0.6'
 
 
 class FlaskRedis(object):
-    def __init__(self, app=None, config_prefix='REDIS'):
+    def __init__(self, app=None, strict=False, config_prefix='REDIS'):
         self._provider_class = None
         self._redis_client = None
         self.config_prefix = config_prefix
 
         if app is not None:
-            self.init_app(app)
+            self.init_app(app, strict)
 
     @classmethod
     def from_custom_provider(cls, provider, app=None, **kwargs):
@@ -27,9 +31,11 @@ def from_custom_provider(cls, provider, app=None, **kwargs):
             instance.init_app(app)
         return instance
 
-    def init_app(self, app):
+    def init_app(self, app, strict=False):
         if self._provider_class is None:
-            self._provider_class = _Redis
+            self._provider_class = (
+                redis.StrictRedis if strict else redis.Redis
+            )
 
         redis_url = app.config.get(
             '{0}_URL'.format(self.config_prefix), 'redis://localhost:6379/0'

test_flask_redis.py

@@ -44,6 +44,19 @@ def test_custom_prefix(app):
     assert redis_b.connection_pool.connection_kwargs['db'] == 2
 
 
+def test_strict_parameter(app):
+    '''Test that initializing with the strict parameter set to True will use
+    StrictRedis, and that False will keep using the old Redis class.'''
+
+    redis = FlaskRedis(app, strict=True)
+    assert redis._redis_client is not None
+    assert type(redis._redis_client).__name__ == 'StrictRedis'
+
+    redis = FlaskRedis(app, strict=False)
+    assert redis._redis_client is not None
+    assert type(redis._redis_client).__name__ == 'Redis'
+
+
 def test_custom_provider(app):
     '''Test that FlaskRedis can be instructed to use a different Redis client,
     like StrictRedis'''