[fix] limiter: prevent loading cached index html when redirected

The redirection to index lets client requests CSS token, if somehow they haven't been.
We need to ensure the html isn't cached so the latest token can be retrieved.

searx/botdetection/ip_limit.py

@@ -123,7 +123,9 @@ def filter_request(
         )
         if c > SUSPICIOUS_IP_MAX:
             logger.error("BLOCK: too many request from %s in SUSPICIOUS_IP_WINDOW (redirect to /)", network)
-            return flask.redirect(flask.url_for('index'), code=302)
+            response = flask.redirect(flask.url_for('index'), code=302)
+            response.headers["Cache-Control"] = "no-store, max-age=0"
+            return response
 
         c = incr_sliding_window(redis_client, 'ip_limit.BURST_WINDOW' + network.compressed, BURST_WINDOW)
         if c > BURST_MAX_SUSPICIOUS: