Merge pull request #2270 from polygon/fix/etag304

Fix/etag304

tornado/test/web_test.py

@@ -1081,6 +1081,13 @@ class StaticFileTest(WebTestCase):
             'If-None-Match': response1.headers['Etag']})
         self.assertEqual(response2.code, 304)
 
+    def test_static_304_etag_modified_bug(self):
+        response1 = self.get_and_head("/static/robots.txt")
+        response2 = self.get_and_head("/static/robots.txt", headers={
+            'If-None-Match': '"MISMATCH"',
+            'If-Modified-Since': response1.headers['Last-Modified']})
+        self.assertEqual(response2.code, 200)
+
     def test_static_if_modified_since_pre_epoch(self):
         # On windows, the functions that work with time_t do not accept
         # negative values, and at least one client (processing.js) seems

tornado/web.py

@@ -2499,8 +2499,9 @@ class StaticFileHandler(RequestHandler):
 
         .. versionadded:: 3.1
         """
-        if self.check_etag_header():
-            return True
+        # If client sent If-None-Match, use it, ignore If-Modified-Since
+        if self.request.headers.get('If-None-Match'):
+            return self.check_etag_header()
 
         # Check the If-Modified-Since, and don't send the result if the
         # content has not been modified