Skip If-Modified-Since check when client sends If-None-Match

bottle.py

@@ -2908,17 +2908,20 @@ def static_file(filename, root,
                                    clen, filename)
         etag = hashlib.sha1(tob(etag)).hexdigest()
 
+    inm = getenv('HTTP_IF_NONE_MATCH')
+
     if etag:
         headers['ETag'] = etag
-        check = getenv('HTTP_IF_NONE_MATCH')
-        if check and check == etag:
+        if inm and inm == etag:
             return HTTPResponse(status=304, **headers)
 
-    ims = getenv('HTTP_IF_MODIFIED_SINCE')
-    if ims:
-        ims = parse_date(ims.split(";")[0].strip())
-    if ims is not None and ims >= int(stats.st_mtime):
-        return HTTPResponse(status=304, **headers)
+    # If client has If-None-Match, ignore If-Modified-Since.
+    if not inm:
+        ims = getenv('HTTP_IF_MODIFIED_SINCE')
+        if ims:
+            ims = parse_date(ims.split(";")[0].strip())
+        if ims is not None and ims >= int(stats.st_mtime):
+            return HTTPResponse(status=304, **headers)
 
     body = '' if request.method == 'HEAD' else open(filename, 'rb')
 

docs/changelog.rst

@@ -56,6 +56,7 @@ Support for Python 2.5 was marked as deprecated since 0.12. We decided to go a s
 These changes might require special care when updating.
 
 * Signed cookies now use a stronger HMAC algorithm by default. This will result in old cookies to appear invalid after the update. Pass an explicit ``digestmod=hashlib.md5`` to :meth:`Request.get_cookie` and :meth:`Response.set_cookie` to get the old behavior.
+* ``If-None-Match`` has precedence when used in combination with ``If-Modified-Since``, skip ``If-Modified-Since`` check even if ``If-None-Match`` check fails.
 
 .. rubric:: Other Improvements
 * Bottle() instances are now context managers. If used in a with-statement, the default application changes to the specific instance and the shortcuts for many instance methods can be used.

test/test_sendfile.py

@@ -90,12 +90,12 @@ def test_ims(self):
         self.assertEqual(open(__file__,'rb').read(), static_file(basename, root=root).body.read())
 
     def test_etag(self):
-        """ SendFile: If-Modified-Since"""
+        """ SendFile: If-None-Match"""
         res = static_file(basename, root=root)
         self.assertTrue('ETag' in res.headers)
         self.assertEqual(200, res.status_code)
         etag = res.headers['ETag']
-        
+
         request.environ['HTTP_IF_NONE_MATCH'] = etag
         res = static_file(basename, root=root)
         self.assertTrue('ETag' in res.headers)
@@ -107,7 +107,12 @@ def test_etag(self):
         self.assertTrue('ETag' in res.headers)
         self.assertNotEqual(etag, res.headers['ETag'])
         self.assertEqual(200, res.status_code)
-
+
+        # test ignore If-Modified-Since when If-None-Match checked failed.
+        request.environ['HTTP_IF_NONE_MATCH'] = '123456'
+        request.environ['HTTP_IF_MODIFIED_SINCE'] = time.strftime("%a, %d %b %Y %H:%M:%S GMT", time.gmtime())
+        res = static_file(basename, root=root)
+        self.assertEqual(200, res.status_code)
 
     def test_download(self):
         """ SendFile: Download as attachment """