Yeah, I think it sounds useful. Thanks, Brad
On Tue, Oct 18, 2011 at 7:11 AM, Salvatore Orlando <[email protected]> wrote: > Is this something we might consider for Quantum as well as concerns resource > extensions? > > Salvatore > > -----Original Message----- > From: openstack-bounces+salvatore.orlando=eu.citrix....@lists.launchpad.net > [mailto:openstack-bounces+salvatore.orlando=eu.citrix....@lists.launchpad.net] > On Behalf Of Kevin L. Mitchell > Sent: 18 October 2011 00:53 > To: [email protected] > Subject: [Openstack] Change to api-paste.ini > > Just writing to let everyone know that there has been a minor change in > api-paste.ini introduced by my recent XML templates merge-prop. The line in > question is the pipeline for [pipeline:openstackapi11]: the addition of the > serialize middleware just before the extensions middleware. Below you will > find a [filter:serialize] section that should also be added, but I would also > like to point out that Brian Waldon's recent change, which nuked the > Openstack v1.0 API, also completely removed the [pipeline:openstackapi10] > section. > > [filter:serialize] > paste.filter_factory = > nova.api.openstack.wsgi:LazySerializationMiddleware.factory > > I'll finish this email with a brief description of the import of the change. > The tl;dr summary is: It is now possible to write request extensions without > having to deserialize and then reserialize the response body. > > The longer version: The XML templates code replaces most of our current XML > serializations with an XML template system; instead of hand-coding conversion > to XML, which is what we were doing before, you construct a template (in a > fashion similar to how you constructed the XML directly; templates are > deliberately designed to have a similar interface). That template is then > passed an object, which it serializes into an XML tree. > > The key innovation is the ability to create slave templates. A slave > template has just the basic tree information, plus any additional attributes > or elements necessary to serialize data that the original master template did > not know about. The slave template can then be attached to the master > template, and when the master template is rendered, the patches proposed by > the slave template will also be rendered. > > Another important point is that serialization can now be done lazily, which > is the purpose of the serialization middleware; when installed, it sets a > WSGI environment variable that causes the serializer (and associated > template, if any) to be inserted into the environment. > > These two innovations together make request extensions possible; up until > now, if someone wanted to build an extension that modified a request, one > would have to discern the type of the data, deserialize it, add the > additional data, then reserialize it, probably with another hand-coded XML > serializer, if the requested representation type was XML. > Now, the request extension handlers are passed the object (rather than having > to pull it out of response.body) and can modify it, and/or attach slave > templates to the template in the "nova.template" WSGI environment variable. > -- > Kevin L. Mitchell <[email protected]> > > This email may include confidential information. If you received it in error, > please delete it. > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : [email protected] > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > > -- > Mailing list: https://launchpad.net/~netstack > Post to : [email protected] > Unsubscribe : https://launchpad.net/~netstack > More help : https://help.launchpad.net/ListHelp > -- Mailing list: https://launchpad.net/~netstack Post to : [email protected] Unsubscribe : https://launchpad.net/~netstack More help : https://help.launchpad.net/ListHelp
