Add clj-time Intervals/DateTime for :max-age and :expires (fixes #55)

- Add a test for :max-age and :expires to (wrap-cookies ...). There were
  no real tests to exercise the base input cases (int, string) which the
  comment block states. This test just makes sure it fulfils that
  contract.
- clj-time is now a project dependency
- :max-age accepts an Interval as input. Updated (write-attr-map ...) to
  accept an Interval (from JodaTime) as well as an int. The interface
  from clj-time is used.
- :expires accepts a DateTime object. It converts the DateTime object in
  the equivalent RFC822 which the cookie spec requires.
- Added pre-conditions for :max-age and :expires to make sure that they
  only accept Interval and DateTime, respectively.

@@ -5,6 +5,7 @@
                  [commons-codec "1.6"]
                  [commons-io "2.1"]
                  [commons-fileupload "1.2.1"]
-                 [javax.servlet/servlet-api "2.5"]]
+                 [javax.servlet/servlet-api "2.5"]
+                 [clj-time "0.3.7"]]
   :profiles
   {:dev {:dependencies [[org.clojure/clojure-contrib "1.2.0"]]}})

@@ -1,6 +1,9 @@
 (ns ring.middleware.cookies
   "Cookie manipulation."
-  (:require [ring.util.codec :as codec]))
+  (:require [ring.util.codec :as codec])
+  (:use [clj-time.core :only (in-secs)]
+        [clj-time.format :only (formatters unparse)])
+  (:import (org.joda.time Interval DateTime)))
 
 (def ^{:private true
        :doc "HTTP token: 1*<any CHAR except CTLs or tspecials>. See RFC2068"}
@@ -91,7 +94,11 @@
   "Is the attribute valid?"
   [[key value]]
   (and (contains? set-cookie-attrs key)
-       (not (.contains (str value) ";"))))
+       (not (.contains (str value) ";"))
+       (case key
+         :max-age (or (instance? Interval value) (integer? value))
+         :expires (or (instance? DateTime value) (string? value))
+         true)))
 
 (defn- write-attr-map
   "Write a map of cookie attributes to a string."
@@ -100,9 +107,11 @@
   (for [[key value] attrs]
     (let [attr-name (name (set-cookie-attrs key))]
       (cond
-        (true? value)  (str ";" attr-name)
-        (false? value) ""
-        :else          (str ";" attr-name "=" value)))))
+       (instance? Interval value) (str ";" attr-name "=" (in-secs value))
+       (instance? DateTime value) (str ";" attr-name "=" (unparse (formatters :rfc822) value))
+       (true? value)  (str ";" attr-name)
+       (false? value) ""
+       :else (str ";" attr-name "=" value)))))
 
 (defn- write-cookies
   "Turn a map of cookies into a seq of strings for a Set-Cookie header."

@@ -1,6 +1,7 @@
 (ns ring.middleware.test.cookies
   (:use clojure.test
-        ring.middleware.cookies))
+        ring.middleware.cookies
+        [clj-time.core :only (interval date-time)]))
 
 (deftest wrap-cookies-basic-cookie
   (let [req  {:headers {"cookie" "a=b"}}
@@ -88,3 +89,57 @@
   (let [response {:cookies {"a" {:value "foo" :invalid true}}}
         handler  (wrap-cookies (constantly response))]
     (is (thrown? AssertionError (handler {})))))
+
+(deftest wrap-cookies-accepts-max-age
+  (let [cookies {"a" {:value "b", :path "/",
+                      :secure true, :http-only true,
+                      :max-age 123}}
+        handler (constantly {:cookies cookies})
+        resp    ((wrap-cookies handler) {})]
+    (is (= {"Set-Cookie" (list "a=b;Path=/;Secure;HttpOnly;Max-Age=123")}
+           (:headers resp)))))
+
+(deftest wrap-cookies-accepts-expires
+  (let [cookies {"a" {:value "b", :path "/",
+                      :secure true, :http-only true,
+                      :expires "123"}}
+        handler (constantly {:cookies cookies})
+        resp    ((wrap-cookies handler) {})]
+    (is (= {"Set-Cookie" (list "a=b;Path=/;Secure;HttpOnly;Expires=123")}
+           (:headers resp)))))
+
+(deftest wrap-cookies-accepts-max-age-from-clj-time
+  (let [cookies {"a" {:value "b", :path "/",
+                      :secure true, :http-only true,
+                      :max-age (interval (date-time 2012)
+                                         (date-time 2015))}}
+        handler (constantly {:cookies cookies})
+        resp    ((wrap-cookies handler) {})
+        max-age 94694400]
+    (is (= {"Set-Cookie" (list (str "a=b;Path=/;Secure;HttpOnly;Max-Age=" max-age))}
+           (:headers resp)))))
+
+(deftest wrap-cookies-accepts-expires-from-clj-time
+  (let [cookies {"a" {:value "b", :path "/",
+                      :secure true, :http-only true,
+                      :expires (date-time 2015 12 31)}}
+        handler (constantly {:cookies cookies})
+        resp    ((wrap-cookies handler) {})
+        expires "Thu, 31 Dec 2015 00:00:00 +0000"]
+    (is (= {"Set-Cookie" (list (str "a=b;Path=/;Secure;HttpOnly;Expires=" expires))}
+           (:headers resp)))))
+
+(deftest wrap-cookies-throws-exception-when-not-using-intervals-correctly
+  (let [cookies {"a" {:value "b", :path "/",
+                      :secure true, :http-only true,
+                      :expires (interval (date-time 2012)
+                                         (date-time 2015))}}
+        handler (constantly {:cookies cookies})]
+    (is (thrown? AssertionError ((wrap-cookies handler) {})))))
+
+(deftest wrap-cookies-throws-exception-when-not-using-datetime-correctly
+  (let [cookies {"a" {:value "b", :path "/",
+                      :secure true, :http-only true,
+                      :max-age (date-time 2015 12 31)}}
+        handler (constantly {:cookies cookies})]
+    (is (thrown? AssertionError ((wrap-cookies handler) {})))))