Support caching for instance list.

master/product/Vifib/Tool/VifibRestApiV1Tool.py

@@ -387,6 +387,8 @@ class InstancePublisher(GenericPublisher):
       self.REQUEST.response.setBody(jsonify(d))
     return self.REQUEST.response
 
+  software_instance_module = 'software_instance_module'
+  @supportModifiedSince('software_instance_module')
   @requireHeader({'Accept': 'application/json'})
   def __instance_list(self):
     kw = dict(
@@ -402,6 +404,10 @@ class InstancePublisher(GenericPublisher):
       # no results, so nothing to return
       self.REQUEST.response.setStatus(204)
     else:
+      self.REQUEST.response.setHeader('Last-Modified',
+        rfc1123_date(self.getPortalObject().software_instance_module\
+          .bobobase_modification_time()))
+      self.REQUEST.response.setHeader('Cache-Control', 'must-revalidate')
       self.REQUEST.response.setStatus(200)
       self.REQUEST.response.setBody(jsonify(d))
     return self.REQUEST.response