From dcbcd94db89a8e73ebc3089a860575bbeb8d1708 Mon Sep 17 00:00:00 2001
From: Daniel Hartwig <address@hidden>
Date: Sun, 27 Nov 2011 18:25:55 +0800
Subject: [PATCH] Permit non-date values for "Expires" header.

* module/web/http.scm ("Expires"): Permit non-date values.
---
 module/web/http.scm            |   20 +++++++++++++++++++-
 test-suite/tests/web-http.test |    1 +
 2 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/module/web/http.scm b/module/web/http.scm
index dc742a1..5eb2e90 100644
--- a/module/web/http.scm
+++ b/module/web/http.scm
@@ -1500,7 +1500,25 @@ phrase\"."
 
 ;; Expires = HTTP-date
 ;;
-(declare-date-header! "Expires")
+;; ...
+;; HTTP/1.1 clients and caches MUST treat other invalid date formats,
+;; especially including the value "0", as in the past (i.e., "already
+;; expired").
+;;
+(declare-header! "Expires"
+  (lambda (str)
+    (or (false-if-exception (parse-date str))
+        str))
+  (lambda (val)
+    (or (string? val) (date? val)))
+  (lambda (val port)
+    (cond
+     ((string? val)
+      (display val port))
+     ((date? val)
+      (write-date val port))
+     (else
+      (bad-header-component 'expires val)))))
 
 ;; Last-Modified = HTTP-date
 ;;
diff --git a/test-suite/tests/web-http.test b/test-suite/tests/web-http.test
index b6abbf3..c881223 100644
--- a/test-suite/tests/web-http.test
+++ b/test-suite/tests/web-http.test
@@ -134,6 +134,7 @@
   (pass-if-parse expires "Tue, 15 Nov 1994 08:12:31 GMT"
                  (string->date "Tue, 15 Nov 1994 08:12:31 +0000"
                          "~a, ~d ~b ~Y ~H:~M:~S ~z"))
+  (pass-if-parse expires "0" "0")
   (pass-if-parse last-modified "Tue, 15 Nov 1994 08:12:31 GMT"
                  (string->date "Tue, 15 Nov 1994 08:12:31 +0000"
                          "~a, ~d ~b ~Y ~H:~M:~S ~z")))
-- 
1.7.2.5