+
+ +
+
+ +
+ +

Route Data Validation

+

Ring route validation works just like with core router, with few differences:

+
    +
  • reitit.ring.spec/validate-spec! should be used instead of reitit.spec/validate-spec! - to support validating all endpoints (:get, :post etc.)
    • +
  • With clojure.spec validation, Middleware can contribute to route spec via :specs key. The effective route data spec is router spec merged with middleware specs.
    • +
+

Example

+

Let's build a ring app with with both explicit (via middleware) and implicit (fully-qualified keys) spec validation.

+

A simple app with spec-validation turned on:

+
(require '[clojure.spec.alpha :as s])
+(require '[reitit.ring :as ring])
+(require '[reitit.ring.spec :as rrs])
+(require '[reitit.spec :as rs])
+(require '[expound.alpha :as e])
+
+(defn handler [_]
+  {:status 200, :body "ok"})
+
+(def app
+  (ring/ring-handler
+    (ring/router
+      ["/api"
+       ["/public"
+        ["/ping" {:get handler}]]
+       ["/internal"
+        ["/users" {:get {:handler handler}
+                   :delete {:handler handler}}]]]
+      {:validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+
+

All good:

+
(app {:request-method :get
+      :uri "/api/internal/users"})
+; {:status 200, :body "ok"}
+
+

Explicit specs via middleware

+

Middleware that requires :zone to be present in route data:

+
(s/def ::zone #{:public :internal})
+
+(def zone-middleware
+  {:name ::zone-middleware
+   :spec (s/keys :req-un [::zone])
+   :wrap (fn [handler]
+           (fn [request]
+             (let [zone (-> request (ring/get-match) :data :zone)]
+               (println zone)
+               (handler request))))})
+
+

Missing route data fails fast at router creation:

+
(def app
+  (ring/ring-handler
+    (ring/router
+      ["/api" {:middleware [zone-middleware]} ;; <--- added
+       ["/public"
+        ["/ping" {:get handler}]]
+       ["/internal"
+        ["/users" {:get {:handler handler}
+                   :delete {:handler handler}}]]]
+      {:validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+; CompilerException clojure.lang.ExceptionInfo: Invalid route data:
+;
+; -- On route -----------------------
+;
+; "/api/public/ping" :get
+;
+; -- Spec failed --------------------
+;
+; {:middleware ...,
+;  :handler ...}
+;
+; should contain key: `:zone`
+;
+; |   key |  spec |
+; |-------+-------|
+; | :zone | :zone |
+;
+;
+; -- On route -----------------------
+;
+; "/api/internal/users" :get
+;
+; -- Spec failed --------------------
+;
+; {:middleware ...,
+;  :handler ...}
+;
+; should contain key: `:zone`
+;
+; |   key |  spec |
+; |-------+-------|
+; | :zone | :zone |
+;
+;
+; -- On route -----------------------
+;
+; "/api/internal/users" :delete
+;
+; -- Spec failed --------------------
+;
+; {:middleware ...,
+;  :handler ...}
+;
+; should contain key: `:zone`
+;
+; |   key |  spec |
+; |-------+-------|
+; | :zone | :zone |
+
+

Adding the :zone to route data fixes the problem:

+
(def app
+  (ring/ring-handler
+    (ring/router
+      ["/api" {:middleware [zone-middleware]}
+       ["/public" {:zone :public} ;; <--- added
+        ["/ping" {:get handler}]]
+       ["/internal" {:zone :internal} ;; <--- added
+        ["/users" {:get {:handler handler}
+                   :delete {:handler handler}}]]]
+      {:validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+
+(app {:request-method :get
+      :uri "/api/internal/users"})
+; in zone :internal
+; => {:status 200, :body "ok"}
+
+

Implicit specs

+

By design, clojure.spec validates all fully-qualified keys with s/keys specs even if they are not defined in that keyset. Validation in implicit but powerful.

+

Let's reuse the wrap-enforce-roles from Dynamic extensions and define specs for the data:

+
(require '[clojure.set :as set])
+
+(s/def ::role #{:admin :manager})
+(s/def ::roles (s/coll-of ::role :into #{}))
+
+(defn wrap-enforce-roles [handler]
+  (fn [{:keys [::roles] :as request}]
+    (let [required (some-> request (ring/get-match) :data ::roles)]
+      (if (and (seq required) (not (set/subset? required roles)))
+        {:status 403, :body "forbidden"}
+        (handler request)))))
+
+

wrap-enforce-roles silently ignores if the ::roles is not present:

+
(def app
+  (ring/ring-handler
+    (ring/router
+      ["/api" {:middleware [zone-middleware
+                            wrap-enforce-roles]} ;; <--- added
+       ["/public" {:zone :public}
+        ["/ping" {:get handler}]]
+       ["/internal" {:zone :internal}
+        ["/users" {:get {:handler handler}
+                   :delete {:handler handler}}]]]
+      {:validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+
+(app {:request-method :get
+      :uri "/api/zones/admin/ping"})
+; in zone :internal
+; => {:status 200, :body "ok"}
+
+

But fails if they are present and invalid:

+
(def app
+  (ring/ring-handler
+    (ring/router
+      ["/api" {:middleware [zone-middleware
+                            wrap-enforce-roles]}
+       ["/public" {:zone :public}
+        ["/ping" {:get handler}]]
+       ["/internal" {:zone :internal}
+        ["/users" {:get {:handler handler
+                         ::roles #{:manager} ;; <--- added
+                   :delete {:handler handler
+                            ::roles #{:adminz}}}]]] ;; <--- added
+      {:validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+; CompilerException clojure.lang.ExceptionInfo: Invalid route data:
+;
+; -- On route -----------------------
+;
+; "/api/internal/users" :delete
+;
+; -- Spec failed --------------------
+;
+; {:middleware ...,
+;  :zone ...,
+;  :handler ...,
+;  :user/roles #{:adminz}}
+;                ^^^^^^^
+;
+; should be one of: `:admin`,`:manager`
+
+

Pushing the data to the endpoints

+

Ability to define (and reuse) route-data in sub-paths is a powerful feature, but having data scattered all around might be harder to reason about. There is always an option to push all data to the endpoints.

+
(def app
+  (ring/ring-handler
+    (ring/router
+      ["/api"
+       ["/public"
+        ["/ping" {:zone :public
+                  :get handler
+                  :middleware [zone-middleware
+                               wrap-enforce-roles]}]]
+       ["/internal"
+        ["/users" {:zone :internal
+                   :middleware [zone-middleware
+                                wrap-enforce-roles]
+                   :get {:handler handler
+                         ::roles #{:manager}}
+                   :delete {:handler handler
+                            ::roles #{:admin}}}]]]
+      {:validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+
+

Or even flatten the routes:

+
(def app
+  (ring/ring-handler
+    (ring/router
+      [["/api/public/ping" {:zone :public
+                            :get handler
+                            :middleware [zone-middleware
+                                         wrap-enforce-roles]}]
+       ["/api/internal/users" {:zone :internal
+                               :middleware [zone-middleware
+                                            wrap-enforce-roles]
+                               :get {:handler handler
+                                     ::roles #{:manager}}
+                               :delete {:handler handler
+                                        ::roles #{:admin}}}]]
+      {:validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+
+

The common Middleware can also be pushed to the router, here cleanly separing behavior and data:

+
(def app
+  (ring/ring-handler
+    (ring/router
+      [["/api/public/ping" {:zone :public
+                            :get handler}]
+       ["/api/internal/users" {:zone :internal
+                               :get {:handler handler
+                                     ::roles #{:manager}}
+                               :delete {:handler handler
+                                        ::roles #{:admin}}}]]
+      {:middleware [zone-middleware wrap-enforce-roles]
+       :validate rrs/validate-spec!
+       ::rs/explain e/expound-str})))
+
+ + +
+ +
+
+
+ +

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