Provide tests for issue #647 and improve efficiency

Provide test cases for redirects stripping out query string.

Don't repeat database query in middleware if there is no query string.

wagtail/wagtailredirects/middleware.py

@@ -13,12 +13,18 @@ class RedirectMiddleware(object):
 
         # Get the path
         path = models.Redirect.normalise_path(request.get_full_path())
+
+        # Get the path without the query string or params
         path_without_query = urlparse(path)[2]
 
         # Find redirect
         try:
             redirect = models.Redirect.get_for_site(request.site).get(old_path=path)
         except models.Redirect.DoesNotExist:
+            if path == path_without_query:
+                # don't try again if we know we will get the same response
+                return response
+
             try:
                 redirect = models.Redirect.get_for_site(request.site).get(old_path=path_without_query)
             except models.Redirect.DoesNotExist:

wagtail/wagtailredirects/tests.py

@@ -67,6 +67,30 @@ class TestRedirects(TestCase):
         self.assertEqual(r.status_code, 302)
         self.assertTrue(r.has_header('Location'))
 
+    def test_redirect_stripping_query_string(self):
+        # Get a client
+        c = Client()
+
+        # Create a redirect which includes a query string
+        redirect_with_query_string = models.Redirect(old_path='/redirectme?foo=Bar', redirect_link='/with-query-string-only')
+        redirect_with_query_string.save()
+
+        # ... and another redirect without the query string
+        redirect_without_query_string = models.Redirect(old_path='/redirectme', redirect_link='/without-query-string')
+        redirect_without_query_string.save()
+
+        # Navigate to the redirect with the query string
+        r_matching_qs = c.get('/redirectme/?foo=Bar')
+        self.assertEqual(r_matching_qs.status_code, 301)
+        self.assertTrue(r_matching_qs.has_header('Location'))
+        self.assertEqual(r_matching_qs['Location'][-23:], '/with-query-string-only')
+
+        # Navigate to the redirect with a different query string
+        # This should strip out the query string and match redirect_without_query_string
+        r_no_qs = c.get('/redirectme/?utm_source=irrelevant')
+        self.assertEqual(r_no_qs.status_code, 301)
+        self.assertTrue(r_no_qs.has_header('Location'))
+        self.assertEqual(r_no_qs['Location'][-21:], '/without-query-string')
 
 class TestRedirectsIndexView(TestCase, WagtailTestUtils):
     def setUp(self):