Ring middleware for parsing query params with clojure.spec

spec_middleware.clj

(defn wrap-query-params-spec [h]
  "Try to parse query params with clojure spec. Look for a spec named like 'query-params/[uri]'
   If found and the spec does not conform, return the explained message"
  (fn [req]
    (try
      (let [query-spec-k (keyword (str "query-params" (:uri req)))
            query-params (keywordize-keys (:query-params req))
            conformed-query-params (s/conform query-spec-k query-params)]
        (if (= :clojure.spec/invalid conformed-query-params)
          (->
            (response {:error-message (s/explain-str query-spec-k query-params)})
            (status 422))
          (h (assoc req :params conformed-query-params))))
      (catch Exception e (h req)))))


;; Usage example, for a route like /coords
(s/def :query-params/coords (s/keys :req-un [:coords/lat :coords/lng]
                                    :opt-un [:result/limit]))