utils: add invalidate_cache to force a new request to be made (#17056)

combo/utils.py

@@ -84,6 +84,7 @@ class Requests(RequestsSession):
     def request(self, method, url, **kwargs):
         remote_service = kwargs.pop('remote_service', None)
         cache_duration = kwargs.pop('cache_duration', 15)
+        invalidate_cache = kwargs.pop('invalidate_cache', False)
         user = kwargs.pop('user', None)
         without_user = kwargs.pop('without_user', False)
         federation_key = kwargs.pop('federation_key', 'auto') # 'auto', 'email', 'nameid'
@@ -150,7 +151,7 @@ class Requests(RequestsSession):
             # handle cache
             cache_key = hashlib.md5(url).hexdigest()
             cache_content = cache.get(cache_key)
-            if cache_content:
+            if cache_content and not invalidate_cache:
                 response = Response()
                 response.status_code = 200
                 response.raw = StringIO(cache_content)

tests/test_requests.py

@@ -1,9 +1,10 @@
 import mock
+import pytest
 import urlparse
 
 from django.contrib.auth.models import AnonymousUser
 
-from combo.utils import requests, check_query
+from combo.utils import requests, check_query, NothingInCacheException
 
 class MockSAMLUser(object):
     name_id = 'r2d2'
@@ -122,3 +123,23 @@ def test_sign_anonymous_user():
         assert query['email'][0] == ''
         assert query['orig'][0] == 'myself'
         assert check_query(querystring, 'secret') == True
+
+def test_requests_cache():
+    with mock.patch('combo.utils.RequestsSession.request') as requests_get:
+        requests_get.return_value = mock.Mock(content='hello world', status_code=200)
+        # default cache, nothing in there
+        assert requests.get('http://cache.example.org/').content == 'hello world'
+        assert requests_get.call_count == 1
+        # now there's something in cache
+        assert requests.get('http://cache.example.org/').content == 'hello world'
+        assert requests_get.call_count == 1
+        # value changed
+        requests_get.return_value = mock.Mock(content='hello second world', status_code=200)
+        assert requests.get('http://cache.example.org/').content == 'hello world'
+        assert requests_get.call_count == 1
+        # force cache invalidation
+        assert requests.get('http://cache.example.org/', invalidate_cache=True).content == 'hello second world'
+        assert requests_get.call_count == 2
+        # check raise_if_not_cached
+        with pytest.raises(NothingInCacheException):
+            requests.get('http://cache.example.org/other', raise_if_not_cached=True)