flask_util.cached: cache werkzeug HTTPExceptions, eg raised by abort/…

…error

catch and return them instead of letting them propagate so that flask-cache can cache them

pallets-eco/flask-caching#444

flask_util.py

@@ -263,8 +263,18 @@ def unless():
                 request.cookies)
 
   def decorator(f):
+    # catch werkzeug HTTPExceptions, eg raised by abort(), and return them
+    # instead of letting them propagate, so that flask-cache can cache them
+    @functools.wraps(f)
+    def httpexception_to_return(*args, **kwargs):
+      try:
+        return f(*args, **kwargs)
+      except HTTPException as e:
+        return e
+
     decorated = cache.cached(timeout.total_seconds(), query_string=True,
-                             response_filter=response_filter, unless=unless)(f)
+                             response_filter=response_filter, unless=unless
+                             )(httpexception_to_return)
 
     # include specified headers in cache key:
     # https://flask-caching.readthedocs.io/en/latest/api.html#flask_caching.Cache.cached

tests/test_flask_util.py

@@ -128,6 +128,25 @@ def error():
     self.assertEqual(500, resp.status_code)
     self.assertEqual(1, calls)
 
+  def test_cached_flask_util_error(self):
+    cache = Cache(self.app)
+    calls = 0
+
+    @self.app.route('/error')
+    @flask_util.cached(cache, datetime.timedelta(days=1))
+    def error():
+      nonlocal calls
+      calls += 1
+      flask_util.error('asdf', status=400)
+
+    resp = self.client.get('/error')
+    self.assertEqual(400, resp.status_code)
+    self.assertEqual(1, calls)
+
+    resp = self.client.get('/error')
+    self.assertEqual(400, resp.status_code)
+    self.assertEqual(1, calls)
+
   def test_cached_headers(self):
     cache = Cache(self.app)
     calls = 0