Add Expires header to favicon controller responses

src/milla/controllers.py

@@ -23,7 +23,8 @@ from one or more of these classes can make things significantly easier.
 :Updater: $Author$
 '''
 
-import milla
+import datetime
+import milla.util
 import pkg_resources
 
 
@@ -53,6 +54,9 @@ class FaviconController(Controller):
        used as the favicon, defaults to 'image/x-icon' (Windows ICO format)
     '''
 
+    #: Number of days in the future to set the cache expiration for the icon
+    EXPIRY_DAYS = 365
+
     def __init__(self, icon=None, content_type='image/x-icon'):
         if icon:
             try:
@@ -72,4 +76,7 @@ class FaviconController(Controller):
         response = milla.Response()
         response.app_iter = self.icon
         response.headers['Content-Type'] = self.content_type
+        expires = (datetime.datetime.utcnow() +
+                   datetime.timedelta(days=self.EXPIRY_DAYS))
+        response.headers['Expires'] = milla.util.http_date(expires)
         return response