Merge pull request #585 from djblue/var-handler

Allow var handlers

doc/advanced/dev_workflow.md

@@ -147,3 +147,19 @@ Let's apply a small change to our ```ns3```. We'll replace our router by two dif
 
 And there you have it, dynamic during dev, performance at production. We have it all !
 
+## Var handlers
+
+You can use a var instead of a function as a `:handler`. This will
+allow you to modify the handler function without rebuilding the reitit
+router.
+
+For example:
+
+```clj
+(def router
+  (ring/router
+    ["/ping" {:get #'my-ns/handler}]))
+```
+
+Now you can reload `my-ns` or redefine `my-ns/handler` and the router
+will use the new definition automatically.

modules/reitit-core/src/reitit/core.cljc

@@ -28,6 +28,10 @@
      :cljs function)
   (expand [this _] {:handler this})
 
+  #?(:clj  clojure.lang.Var
+     :cljs cljs.core.Var)
+  (expand [this _] {:handler this})
+
   nil
   (expand [_ _]))
 

modules/reitit-core/src/reitit/spec.cljc

@@ -38,7 +38,7 @@
 ;;
 
 (s/def ::name keyword?)
-(s/def ::handler fn?)
+(s/def ::handler (s/or :fn fn? :var var?))
 (s/def ::no-doc boolean?)
 (s/def ::conflicting boolean?)
 (s/def ::default-data

test/cljc/reitit/core_test.cljc

@@ -6,6 +6,9 @@
      (:import (clojure.lang ExceptionInfo)
               (reitit.core Router))))
 
+(defn- var-handler [& _]
+  "var-handler")
+
 (deftest reitit-test
 
   (testing "routers handling wildcard paths"
@@ -245,7 +248,11 @@
       (let [router (r/router ["/ping" (constantly "ok")])
             {:keys [result]} (r/match-by-path router "/ping")]
         (is result)
-        (is (= "ok" (result))))))
+        (is (= "ok" (result))))
+      (testing "var handler gets expanded"
+      (let [router (r/router ["/ping" #'var-handler])
+            {:keys [result]} (r/match-by-path router "/ping")]
+        (is (= #'var-handler result))))))
 
   (testing "custom router"
     (let [router (r/router ["/ping"] {:router (fn [_ _]

test/cljc/reitit/ring_test.cljc

@@ -52,6 +52,7 @@
                   ["/api" {:middleware [api-mw]}
                    ["/all" handler]
                    ["/get" {:get handler}]
+                   ["/get-var" {:get {:handler #'handler}}]
                    ["/users" {:middleware [[mw :users]]
                               :get handler
                               :post {:handler handler
@@ -74,6 +75,10 @@
                (app {:uri "/api/get" :request-method :get})))
         (is (= nil (app {:uri "/api/get" :request-method :post}))))
 
+      (testing "var handler"
+        (is (= {:status 200, :body [:api :ok]}
+               (app {:uri "/api/get-var" :request-method :get}))))
+
       (testing "expanded method handler"
         (is (= {:status 200, :body [:api :users :ok]}
                (app {:uri "/api/users" :request-method :get}))))

test/cljc/reitit/spec_test.cljc

@@ -101,6 +101,11 @@
           ["/api" {:name "kikka"}]
           {:validate rs/validate}))))
 
+  (testing "handler can be a var"
+    (is (r/router? (r/router
+                    ["/api" {:handler #'identity}]
+                    {:validate rs/validate}))))
+
   (testing "spec can be overridden"
     (is (r/router? (r/router
                     ["/api" {:handler "identity"}]