Xavier Hanin wrote:
Hi,
I'm currently using wicketstuff-push to push events to a page and it
works
pretty well, but not well enough. Before trying to move to a comet based
implementation, I would like to improve the timer based
implementation. In
the current implementation you got as many AjaxTimer as you install
the push
on components on the same page. So if you have three components requiring
push, you will have three requests each x seconds, to poll for push
events
from the three components. This would be much more efficient if I had
only
one request polling for all push events sent by all components on the
page...
Hence my first thought was to add the timer behavior to the page
instead of
the component, and verify that the same kind of behavior is not already
installed before installing a new one. The problem is that when I install
the behavior the component doesn't know its page. So I have to do
something
at this time, and then later when I know the page make sure that only one
behavior is actually rendered.
I see two solutions to this problem:
- Add one timer behavior to each component (as today), and then when
rendering the component use the wasRendered/markRendered methods of
IHeaderResponse to render only one of them (using the isEnabled method to
disable it if another similar one has already been rendered). But then I
will have to update all the non rendered behaviors so that push events
sent
to them are actually sent to the only behavior which is rendered.
- Modify the API of the push service and ask to enable push on a page
before
actually using push on components on the page. This would actually
install a
unique timer behavior on the page. Then when installing push on a
component
I could simply add something which could be located by the unique
timer on
the page to collect all push events (maybe a disabled behavior)
Now that I expose the two options I think I prefer the first one. But I
would like to gather feedback from experienced wicket developers to
see if
I'm not missing something or if you have better ideas about how to
implement
what I want.
Hy Xavier,
I've got an idea but I don't know if it will be convenient:
TimerPushBehavior should not extends AjaxTimerBehavior.
TimerPushBehavior could now do :
- Adding a javascript(jsMain) in the header (using a static id - render
once). This javascript can manage ajax timer on a specific callback url.
- Each TimerPushBehavior registers its component id on the previous
added javascript(jsMain)
- When a callback is received by the first added behavior:
* get all id registered in jsMain (sent to the behavior as
parameters of the callbackUrl)
* look for each child(server side) by they component id (IVisitor)
* look for TimerPushBehavior on each child
* call onTimer method on each TimerPushBehavior of each Child
it is may be a little bit hacked but it can be a solution.
WDYT?
--
Vincent
Thanks,
Xavier
