Simple su implementation

src/cemerick/friend.clj

@@ -2,6 +2,7 @@
   (:require [cemerick.friend.util :as util]
             [clojure.set :as set])
   (:use (ring.util [response :as response :only (redirect)])
+        (ring.middleware [session :as session :only (wrap-session)])
         [slingshot.slingshot :only (throw+ try+)]
         [clojure.core.incubator :only (-?>)])
   (:refer-clojure :exclude (identity)))
@@ -122,6 +123,19 @@ any funny-business related to the dynamic binding of `*identity*`."
                      identity-or-ring-map)]
       (-> identity :authentications (get (:current identity))))))
 
+(defn switch-user
+  "Simply updates current authentication. Receives a ring
+  handler and a function that returns a user when it receives the
+  request.
+
+  This function assumes that you somehow already have several
+  authentications."
+  [handler current-auth-fn]
+  (fn [request]
+    (if-let [response ((wrap-session handler) request)]
+      (assoc-in response [:session ::identity :current]
+                (current-auth-fn request)))))
+
 (def ^{:doc "Returns true only if the provided request/response has no identity.
 Equivalent to (complement current-authentication)."}
       anonymous? (complement current-authentication))

test/test_friend/functional.clj

@@ -161,6 +161,17 @@
     (is (= (page-bodies "/")) (http/get (url "/logout")))
     (is (= (page-bodies "/login") (:body (http/get (url "/admin")))))))
 
+; su
+(deftest alternate-users
+  (binding [clj-http.core/*cookie-store* (clj-http.cookies/cookie-store)]
+    (http/post (url "/login") {:form-params {:username "root" :password "admin_password"}})
+    (is (= "root" (:body (http/get (url "/echo-identity")))))  
+    (http/post (url "/login") {:form-params {:username "jane" :password "user_password"}})
+    (is (= "jane" (:body (http/get (url "/echo-identity")))))
+    (http/post (url "/switch-user") {:form-params {:user "root"}})
+    (is (= "root" (:body (http/get (url "/echo-identity")))))  
+    (http/post (url "/switch-user") {:form-params {:user "jane"}})
+    (is (= "jane" (:body (http/get (url "/echo-identity")))))))
+
 ;;;; TODO
 ; requires-scheme
-; su

test/test_friend/mock_app.clj

@@ -57,11 +57,20 @@
   (GET "/login" request (page-bodies (:uri request)))
   (GET "/free-api" request (api-call 99))
   (friend/logout (ANY "/logout" request (resp/redirect "/")))
+  (friend/switch-user
+    (POST "/switch-user" request (resp/response "User switched"))
+    #(-> % :params :user))
 
   (GET "/echo-roles" request (friend/authenticated
                                (-> (friend/current-authentication request)
                                  (select-keys [:roles])
                                  json-response)))
+
+  (GET "/echo-identity" request  (-> request
+                                     :session
+                                     :cemerick.friend/identity
+                                     :current
+                                     resp/response))
 
   ;;;;; session integrity
   (GET "/session-value" request