More granular control over query handling

modules/middleware/allowQuery.js

@@ -0,0 +1,27 @@
+import createSearch from '../utils/createSearch.js';
+
+/**
+ * Reject URLs with invalid query parameters to increase cache hit rates.
+ */
+export default function allowQuery(validKeys = []) {
+  if (!Array.isArray(validKeys)) {
+    validKeys = [validKeys];
+  }
+
+  return (req, res, next) => {
+    const keys = Object.keys(req.query);
+
+    if (!keys.every(key => validKeys.includes(key))) {
+      const newQuery = keys
+        .filter(key => validKeys.includes(key))
+        .reduce((query, key) => {
+          query[key] = req.query[key];
+          return query;
+        }, {});
+
+      return res.redirect(302, req.baseUrl + req.path + createSearch(newQuery));
+    }
+
+    next();
+  };
+}