Re: [Engine-devel] REST API calls from the GUI

From: "Michael Pasternak" <mpastern(a)redhat.com&gt; To: "Libor Spevak" <lspevak(a)redhat.com&gt; Cc: engine-devel(a)ovirt.org, "Daniel Erez" <derez(a)redhat.com&gt;, "Gilad Chaplik" <gchaplik(a)redhat.com&gt;, "Einav Cohen" <ecohen(a)redhat.com&gt;, arch(a)ovirt.org Sent: Wednesday, February 13, 2013 12:55:36 PM Subject: Re: [Engine-devel] REST API calls from the GUI Hi Libor, This issue came across in one of the conversations i had with UX folks, but since we didn't end up with any conclusion/road map (nor discussed it properly to hear other thoughts), this is a perfect place to start this discussion, Intuitively REST is a way to go with GWT AJAX calls --------------------------------------------------- pros ==== - api data objects can be reused by generating java classes (using jaxb) from the rest schema [1] - no backend logic will be duplicated as api abstracts the backend exposing RESTful collection/resources to operate on - development against api is "easy" as api describes itself in RSDL [2] cons ==== - implementing transport layer (HTTP) under GWT - implementing own j2xml/json/yaml/... marshalling layer - implementing own error handling mechanism - implementing REST callback mechanism (in GWT) - constant maintenance of the data objects generated from the api - painful for Java developers Java-SDK -------- pros ==== - abstracts transport layer (leaving developer in standard Java api) - typesafe code (no need to mess with XML bulks) - has own data objects to work with - abstracts authentication/authorization (kerberos/cookie/session/etc.) - since SDK is auto-generated, it can be easily extended with required features to support UI (such as callback infrastructure for instance) cons ==== - has to be converted in to Javascript (not sure what the impacts are in terms of AJAX calls/etc.) - probably much more cons that we're not aware of and will have to figure out with POC thoughts?

[1] http[s]://server[:port]/api?schema [2] http[s]://server[:port]/api?rsdl On 02/12/2013 06:13 PM, Libor Spevak wrote: > Hi, > > I would like to ask, if there have been discussions about an option > to call REST API services directly from the Frontend (GWT layer)? > GWT compiles Java frontend-side to > Javascript, calls to backend services are performed "transparently" > by the framework using AJAX support. But, there is still a need to > have a special set of data objects > and the server-side logic can duplicate. > > Java REST API SDK enables to build "thick" client. The calls are > realized using e.g. Apache HttClient and supported libraries. I > think the requirements of GWT can be a > little bit different, but something overlaps. > > I found several links about REST API support from GWT, so there is > something for inspiration... > > - http://www.spiffyui.org/ > - http://www.zackgrossbart.com/hackito/gwt-rest/ > - http://code.google.com/p/gwt-rest/ > - http://restygwt.fusesource.org/ > > But, do you think it would be useful and what drawbacks can occur > (authentication, authorization, response times, need to support > larger set of services, painful > refactoring, ...)? > > Regards, > Libor > > _______________________________________________ > Engine-devel mailing list > Engine-devel(a)ovirt.org > http://lists.ovirt.org/mailman/listinfo/engine-devel -- Michael Pasternak RedHat, ENG-Virtualization R&D