1 files changed, 26 insertions, 0 deletions
diff --git a/web/lib/view_utils.py b/web/lib/view_utils.py
new file mode 100644
index 00000000..d4c119da
--- /dev/null
+++ b/web/lib/view_utils.py
@@ -0,0 +1,26 @@
+from functools import wraps
+from flask import request, Response, make_response
+from web.lib.utils import to_hash
+
+
+def etag_match(func):
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        response = func(*args, **kwargs)
+        if isinstance(response, Response):
+            etag = to_hash(response.data)
+            headers = response.headers
+        elif type(response) is str:
+            etag = to_hash(response)
+            headers = {}
+        else:
+            return response
+        if request.headers.get('if-none-match') == etag:
+            response = Response(status=304)
+            response.headers['Cache-Control'] \
+                    = headers.get('Cache-Control', 'pragma: no-cache')
+        elif not isinstance(response, Response):
+            response = make_response(response)
+        response.headers['etag'] = etag
+        return response
+    return wrapper