Added ring.util.environment and PORT var

src/ring/server/standalone.clj

@@ -1,9 +1,12 @@
 (ns ring.server.standalone
-  (:use [ring.adapter.jetty :only (run-jetty)]))
+  "Functions to start a standalone Ring server."
+  (:use ring.adapter.jetty
+        ring.util.environment))
 
 (defn serve
   "Start a web server to run a handler."
   [handler & [{:as options}]]
+  (let [port (Integer. (*env* "PORT" "5000"))]
     (run-jetty
       handler
-    (merge {:port 5000} options)))
+      (merge {:port port} options))))

src/ring/util/environment.clj

@@ -0,0 +1,11 @@
+(ns ring.util.environment
+  "A namespace managing and reading environment variables.")
+
+(def ^{:dynamic true, :doc "A map of environment variables."}
+  *env* (into {} (System/getenv)))
+
+(defmacro with-env
+  "Merges the supplied map of environment variable into *env*."
+  [env-map & body]
+  `(binding [*env* (merge *env* ~env-map)]
+     ~@body))

test/ring/server/test/standalone.clj

@@ -2,6 +2,7 @@
   (:require [clj-http.client :as http])
   (:use clojure.test
         ring.server.standalone
+        ring.util.environment
         ring.util.response))
 
 (defmacro with-server [server & body]
@@ -11,8 +12,9 @@
        (finally (.stop server#)))))
 
 (deftest serve-test
+  (with-env {"PORT" "4563"}
     (let [handler (constantly (response "Hello World"))]
       (with-server (serve handler {:join? false})
-      (let [resp (http/get "http://localhost:5000")]
+        (let [resp (http/get "http://localhost:4563")]
           (is (= (:status resp) 200))
-        (is (= (:body resp) "Hello World"))))))
+          (is (= (:body resp) "Hello World")))))))