reloading-ring-handler

modules/reitit-ring/src/reitit/ring.cljc

@@ -340,6 +340,22 @@
            nil)))
        {::r/router router}))))
 
+(defn reloading-ring-handler
+  "Returns a ring-handler that recreates the actual ring-handler for each request.
+  Takes a 0-arity function that should return a valid ring-handler. Effectively creates
+  an auto-reloading ring-handler, which is good for REPL-driven development.
+
+  Example:
+
+        ;; for dev-mode, recreate the ring-handler for each request, for prod, just once
+        (let [dev-mode ...
+              f (fn [] (reitit.ring/ring-handler ...)]
+          (if dev-mode (reitit.ring/reloading-ring-handler f) (f)))"
+  [f]
+  (fn
+    ([request] ((f) request))
+    ([request respond raise] ((f) request respond raise))))
+
 (defn get-router [handler]
   (-> handler meta ::r/router))
 

test/cljc/reitit/ring_test.cljc

@@ -736,3 +736,22 @@
                (dotimes [n 100000]
                  (let [body (:body (app {:request-method :get, :uri (str "/" n)}))]
                    (is (= body (str n))))))))))))
+
+(declare routes)
+
+(deftest reloading-ring-handler-test
+  (let [r (fn [body] {:status 200, :body body})]
+    (def routes ["/" (constantly (r "1"))]) ;; initial value
+
+    (let [create-handler (fn [] (ring/ring-handler (ring/router routes)))]
+      (testing "static ring handler does not see underlying route changes"
+        (let [app (create-handler)]
+          (is (= (r "1") (app {:uri "/", :request-method :get})))
+          (def routes ["/" (constantly (r "2"))]) ;; redefine
+          (is (= (r "1") (app {:uri "/", :request-method :get})))))
+
+      (testing "reloading ring handler sees underlying route changes"
+        (let [app (ring/reloading-ring-handler create-handler)]
+          (is (= (r "2") (app {:uri "/", :request-method :get})))
+          (def routes ["/" (constantly (r "3"))]) ;; redefine again
+          (is (= (r "3") (app {:uri "/", :request-method :get}))))))))