Merge pull request #189 from andrewmcveigh/multi-method-decisions

Allow decisions to be multi-methods

src/liberator/core.clj

@@ -71,7 +71,9 @@
 (declare handle-exception)
 
 (defn decide [name test then else {:keys [resource request] :as context}]
-  (if (or (fn? test) (contains? resource name))
+  (if (or (fn? test)
+          (instance? clojure.lang.MultiFn test)
+          (contains? resource name))
     (try
       (let [ftest (or (resource name) test)
             ftest (make-function ftest)

src/liberator/representation.clj

@@ -201,10 +201,6 @@
   (as-response [this context]
     (as-response (render-map-generic this context) context))
 
-  clojure.lang.MultiFn
-  (as-response [multi-fn context]
-    (as-response (multi-fn context) context))
-
   ;; If a string is returned, we should carry out the conversion of both the charset and the encoding.
   String
   (as-response [this {representation :representation}]

src/liberator/util.clj

@@ -5,7 +5,11 @@
            java.util.Date))
 
 (defn make-function [x]
-  (if (or (fn? x) (keyword? x)) x (constantly x)))
+  (if (or (fn? x)
+          (instance? clojure.lang.MultiFn x)
+          (keyword? x))
+    x
+    (constantly x)))
 
 (defn apply-if-function [function-or-value request]
   (if (fn? function-or-value)

test/test_defresource.clj

@@ -11,6 +11,17 @@
 (defresource with-multimethod
   :handle-ok with-multimethod*)
 
+(defmulti with-service-available?-multimethod*
+  (comp :service-available? :request))
+
+(defmethod with-service-available?-multimethod* :available [_] true)
+
+(defmethod with-service-available?-multimethod* :not-available [_] false)
+
+(defresource with-decisions-multimethod
+  :service-available? with-service-available?-multimethod*
+  :handle-ok (fn [_] "with-service-available?-multimethod"))
+
 (defresource without-param
   :handle-ok (fn [_] (format "The text is %s" "test")))
 
@@ -60,7 +71,13 @@
              => {:headers {"Vary" "Accept", "Content-Type" "application/json;charset=UTF-8"}, :body "OK", :status 200})
        (fact "should allow multi methods as handlers"
              (with-multimethod {:request-method :get})
-             => {:headers {"Content-Type" "text/plain;charset=UTF-8"}, :body "with-multimethod", :status 200}))
+             => {:headers {"Content-Type" "text/plain;charset=UTF-8"}, :body "with-multimethod", :status 200})
+       (fact "should allow multi methods as decisions"
+             (with-decisions-multimethod {:request-method :get :service-available? :available})
+             => {:headers {"Content-Type" "text/plain;charset=UTF-8"}, :body "with-service-available?-multimethod", :status 200})
+       (fact "should allow multi methods as decisions alternate path"
+             (with-decisions-multimethod {:request-method :get :service-available? :not-available})
+             => {:headers {"Content-Type" "text/plain;charset=UTF-8"}, :body "Service not available.", :status 503}))
 
 
 (def fn-with-options