8:33 a.m.
It appears to me that the cross-origin issue is caused because the plugin definition is
embedded in the WebAdmin host page that is hosted by the JBoss AS. This then requires
that all plugins also exist within the same origin. Rather than extending the WebAdmin
page with javascript, would it be possible to instead have an API that modifies that page
with extensions? For example, the API tells it to add a new menu item that when launched
would invoke the url registered with the extension. The new page is now rendered in a
distinct window (much like early versions of GWT hosted mode created an embedded browser
window).
-George
-----Original Message-----
From: engine-devel-bounces(a)ovirt.org [mailto:engine-devel-bounces@ovirt.org] On Behalf Of
Vojtech Szocs
Sent: Monday, July 23, 2012 8:27 AM
To: Itamar Heim
Cc: engine-devel
Subject: Re: [Engine-devel] oVirt UI Plugins: Update on current progress
I agree with your points. Deploying custom plugins on Engine JBoss, just for the purpose
of sharing same origin, sounds a bit strange, and complicates things from package
perspective.
As for cross-origin iframe communication issues, there are several ways how to address
them:
- use CORS (Cross-Origin Resource Sharing) when serving plugin HTML pages from outside
Engine JBoss
- use HTML5 Window.postMessage (but its current implementation is typically limited to
String-based communication)
For now, let's stick to the standard way of developing UI plugins (using dedicated
servlet for plugin HTML page).
Vojtech
----- Original Message -----
From: "Itamar Heim" <iheim(a)redhat.com>
To: "Vojtech Szocs" <vszocs(a)redhat.com>
Cc: "engine-devel" <engine-devel(a)ovirt.org>, "Einav Cohen"
<ecohen(a)redhat.com>
Sent: Monday, July 23, 2012 12:16:04 PM
Subject: Re: oVirt UI Plugins: Update on current progress
On 07/23/2012 01:10 PM, Vojtech Szocs wrote:
> it is not supposed to be next to engine.jar, it is supposed to be
> somewhere else entirely, served to clients like any static content
> via a servelt.
If the GWT UI plugin web application won't be deployed on Engine JBoss AS instance,
we'll run into cross-origin iframe communication issues that we'll need to deal
with.
we'll need to solve these in any case for plugins which do have an existing external
service.
In other words, why prevent others to "keep away" from Engine JBoss AS
instance? Why not let them deploy whatever they want next to engine.ear, given that they
are doing this on their own responsibility?
because once we tell people it is ok, it makes it our responsibility to make sure they
don't break during upgrades for example (or worse, not fail the entire engine post an
upgrade).
I'm not saying these are not solvable, but i'd rather not try to handle them on
the first cut of this framework.
> that's not the scope we discussed so far.
> we discussed a 'static' plugin, which can use an external service or
> the REST API.
This was actually option [1] as described in my email below.
From WebAdmin point-of-view, UI plugins are "static", as you wrote. UI plugins
written in GWT, however, can include server-side logic on their own.
Vojtech
----- Original Message -----
From: "Itamar Heim" <iheim(a)redhat.com>
To: "Vojtech Szocs" <vszocs(a)redhat.com>
Cc: "engine-devel" <engine-devel(a)ovirt.org>, "Einav Cohen"
<ecohen(a)redhat.com>
Sent: Monday, July 23, 2012 11:54:14 AM
Subject: Re: oVirt UI Plugins: Update on current progress
On 07/23/2012 12:40 PM, Vojtech Szocs wrote:
>> this implies server side code running on the engine,
>
> Actually, yes and no :) let me explain:
>
> - UI plugins developed in GWT need some context (plugin web
> application deployed next to engine.ear) from which their code will
> be served
it is not supposed to be next to engine.jar, it is supposed to be
somewhere else entirely, served to clients like any static content via
a servelt.
> - UI plugin web applications can contain only static resources (HTML + generated
JavaScript) -> answer is "NO"
> - UI plugin web applications can also contain server-side code (e.g. for GWT RPC)
-> answer is "YES"
that's not the scope we discussed so far.
we discussed a 'static' plugin, which can use an external service or
the REST API.
>
>> which has additional implications on compatibility vs. ui plugins as
>> discussed
>
> I don't think we need to worry about this :)
>
> If a GWT UI plugin web application needs to use Engine functionality, it can:
>
> - use REST API from within UI plugin (JavaScript) code [1]
> - use REST API from within its server-side (Java) code [2]
again, if we want to discuss an approach to making ui plugins which
need server side cooperation not in a separate container of their own
choice, different server, etc. - we can, but lets separate the
discussion on the two.
>
> [1] - will be supported by UI plugin infrastructure [2] - not
> supported by UI plugin infrastructure
>
> Vojtech
>
>
> ----- Original Message -----
> From: "Itamar Heim" <iheim(a)redhat.com>
> To: "Vojtech Szocs" <vszocs(a)redhat.com>
> Cc: "engine-devel" <engine-devel(a)ovirt.org>, "Einav Cohen"
> <ecohen(a)redhat.com>
> Sent: Monday, July 23, 2012 9:10:07 AM
> Subject: Re: oVirt UI Plugins: Update on current progress
>
> On 07/20/2012 11:37 PM, Vojtech Szocs wrote:
>> Last but not least, writing plugins in Google Web Toolkit (GWT)
>> should be as easy as providing your own plugin source page. Just
>> deploy your GWT plugin application on JBoss AS (next to engine.ear),
>> and point to GWT plugin application host page.
>
> this implies server side code running on the engine, which has
> additional implications on compatibility vs. ui plugins as discussed
> so far which would be java script (I'm not against using GWT for them
> if the resulting java script can be packaged for use as a UI plugin,
> but sever side code i prefer to be isolated from engine until we'll
> define engine plugins).
>
>
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