# HG changeset patch
# User Rémi Cardona <remi.cardona@logilab.fr>
# Date 1447955710 -3600
# Node ID 79066409fdcfae7c87e7f78e5500a03c76c75c0c
# Parent  e905c95ccdfb7d4dcf68ab81155b1043e1331728
[web] stop adding an Expires header with all responses

As per RFC 1945 (HTTP 1.0):

    If the date given is equal to or earlier than the value of the Date
    header, the recipient must not cache the enclosed entity.

As per RFC 7234 (HTTP 1.1 Caching):

    If a response includes a Cache-Control field with the max-age
    directive (Section 5.2.2.8), a recipient MUST ignore the Expires
    field.

Bottom line, the Expires header is now handled wherever the
Cache-Control is handled: inside cache managers.

diff -r e905c95ccdfb -r 79066409fdcf web/httpcache.py
--- a/web/httpcache.py	Fri Nov 20 17:13:03 2015 +0100
+++ b/web/httpcache.py	Thu Nov 19 18:55:10 2015 +0100
@@ -31,6 +31,7 @@
 
     def set_headers(self):
         self.req.set_header('Cache-control', 'no-cache')
+        self.req.set_header('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
 
 
 class MaxAgeHTTPCacheManager(NoHTTPCacheManager):
@@ -68,7 +69,7 @@
         try:
             req.set_header('Etag', '"%s"' % self.etag())
         except NoEtag:
-            self.req.set_header('Cache-control', 'no-cache')
+            super(EtagHTTPCacheManager, self).set_headers()
             return
         req.set_header('Cache-control',
                        'must-revalidate,max-age=%s' % self.max_age())
diff -r e905c95ccdfb -r 79066409fdcf web/request.py
--- a/web/request.py	Fri Nov 20 17:13:03 2015 +0100
+++ b/web/request.py	Thu Nov 19 18:55:10 2015 +0100
@@ -730,12 +730,7 @@
         if validators: # if we have no
             modified = any(func(val, self.headers_out) for func, val in validators)
         # Forge expected response
-        if modified:
-            if 'Expires' not in self.headers_out:
-                # Expires header seems to be required by IE7 -- Are you sure ?
-                self.add_header('Expires', 'Sat, 01 Jan 2000 00:00:00 GMT')
-            # /!\ no raise, the function returns and we keep processing the request
-        else:
+        if not modified:
             # overwrite headers_out to forge a brand new not-modified response
             self.headers_out = self._forge_cached_headers()
             if self.http_method() in ('HEAD', 'GET'):
diff -r e905c95ccdfb -r 79066409fdcf web/test/unittest_http.py
--- a/web/test/unittest_http.py	Fri Nov 20 17:13:03 2015 +0100
+++ b/web/test/unittest_http.py	Thu Nov 19 18:55:10 2015 +0100
@@ -253,46 +253,6 @@
         req = _test_cache(hin, hout, method='POST')
         self.assertCache(412, req.status_out, 'not modifier HEAD verb')
 
-    @tag('expires')
-    def test_expires_added(self):
-        #: Check that Expires header is added:
-        #: - when the page is modified
-        #: - when none was already present
-        hin  = [('if-none-match', 'babar'),
-               ]
-        hout = [('etag', 'rhino/really-not-babar'),
-               ]
-        req = _test_cache(hin, hout)
-        self.assertCache(None, req.status_out, 'modifier HEAD verb')
-        value = req.headers_out.getHeader('expires')
-        self.assertIsNotNone(value)
-
-    @tag('expires')
-    def test_expires_not_added(self):
-        #: Check that Expires header is not added if NOT-MODIFIED
-        hin  = [('if-none-match', 'babar'),
-               ]
-        hout = [('etag', 'babar'),
-               ]
-        req = _test_cache(hin, hout)
-        self.assertCache(304, req.status_out, 'not modifier HEAD verb')
-        value = req.headers_out.getHeader('expires')
-        self.assertIsNone(value)
-
-    @tag('expires')
-    def test_expires_no_overwrite(self):
-        #: Check that cache does not overwrite existing Expires header
-        hin  = [('if-none-match', 'babar'),
-               ]
-        DATE = 'Sat, 13 Apr 2012 14:39:32 GM'
-        hout = [('etag', 'rhino/really-not-babar'),
-                ('expires', DATE),
-               ]
-        req = _test_cache(hin, hout)
-        self.assertCache(None, req.status_out, 'not modifier HEAD verb')
-        value = req.headers_out.getRawHeaders('expires')
-        self.assertEqual(value, [DATE])
-
 
 alloworig = 'access-control-allow-origin'
 allowmethods = 'access-control-allow-methods'