On 30.1.2012 23:33, Julien Viet wrote:
On Jan 30, 2012, at 7:45 PM, Julien Viet wrote:
> On Jan 30, 2012, at 5:22 PM, Marek Posolda wrote:
>
>> Hi,
>>
>> I think that it's not ideal how WebAppController processes static
>> resources like images. I have 2 things to point out:
>>
>> 1) Today I found (and fixed) a bug that images are first processed by
>> PortalRequestHandler, even if they should be processed by
>> StaticResourceRequestHandler. Please look at
>>
https://issues.jboss.org/browse/GTNPORTAL-2338 for more details. This is
>> really not good because HTTP header "Cache-Control: no-cache" is
>> returned for every image, and so web browser needs to download images
>> for each HTTP request to portal. I fixed it by adding
>> StaticResourceRequestHandler before PortalRequestHandler into
>> navController configuration, so it should not be the issue anymore.
> in StaticResourceRequestHandler the request is dispatched with the servlet API and
the "default" servlet should setup the proper headers.
>
> could you explain me why having the StaticResourceRequestHandler after the
PortalRequestHandler prevents it ?
"default" servlet dispatched from
StaticResourceRequestHandler does not
add headers. Headers for images (like "Cache-control" header) are added
by ResourceRequestFilter. Problem is that header is overriden by
PortalRequestHandler.
Well, what's going during processing of HTTP request to image (like
http://localhost:8080/portal/something.jpg ) before fix of
GTNPORTAL-2338 is:
- Header "Cache-Control: max-age=2592000,s-maxage=2592000" is added by
ResourceRequestFilter
- Processing is dispatched to WebAppController and there are two
compliant handlers: PortalRequestHandler and StaticResourceRequestHandler
- PortalRequestHandler is first and so image is processed first by it.
And this does not makes sense as it's overriding Cache-Control header
with value "no-cache" and it's calling some operations to
UserPortalConfigService and DataStorage (really does not makes sense).
- Processing by PortalRequestHandler returns false and so it continues
to StaticResourceRequestHandler. This handler dispatches it to "default"
servlet and image is returned to client, but with incorrect header
"Cache-control: no-cache"
The result is that every browser request to portal like
"http://localhost:8080/portal/classic" needs to download all portal
images as they can't be cached on the browser side. Really bandwidth
killer IMO.
By adding StaticResourceRequestHandler before PortalRequestHandler is
processing of images by PortalRequestHandler omited. For details please
look at
https://issues.jboss.org/browse/GTNPORTAL-2338 .
>> 2) Second thing is not so bad but a bit more tricky. The
piece of code
>> in WebAppController:
>>
>> {code}
>> if (!started)
>> {
>>
>> RequestLifeCycle.begin(ExoContainerContext.getCurrentContainer());
>> started = true;
>> }
>> .....
>> processed = handler.execute(new ControllerContext(this,
>> router, req, res, parameters));
>> .....
>> if (started)
>> {
>> RequestLifeCycle.end();
>> }
>> {code}
>>
>> This means that we need to start RequestLifeCycle for processing of
>> every resource including static resource. And startup of some services
>> is quite expensive (like startup of OrganizationService requires startup
>> of Hibernate transaction). In other words, currently we are starting
>> Hibernate transaction for processing images and other static resources.
>>
>> It's obvious that some handlers (PortalRequestHandler,
>> LegacyRequestHandler and probably some others) really need to start
>> RequestLifecycle, but some others like StaticResourceRequestHandler
>> don't need it. So how about postponing the RequestLifecycle.begin from
>> WebAppController to concrete handlers, which really need it? And use
>> some ThreadLocal variable or flag "started" on ControllerContext, so
>> that we can track if RequestLifeCycle.begin has been already started
>> (can be useful to avoid double-start if some resource needs to be
>> processed by more request handlers) ?
> please make an abstract method on WebRequestHandler :
>
> protected abstract boolean getRequiresLifeCycle() that the WebAppController can use
in the loop to replace the condition checked by
>
> if (!started)
>
> by the condition
>
> if (!started&& handler.getRequiresLifeCycle()) { ... }
>
> (which requires to move this block in the
>
> if (handler != null)
> {
> }
>
> block
I just want that the whole request lifecycle stuff keeps confined in the WebAppController
class if we can, as the subclass will likely always or never need a RequestLifecyle to be
triggered.
Thanks, initially I though that some handlers may need to start only
something (for example start only ChromatticManager but not
OrganizationService) but probably does not makes sense to complicate
things because of it. So I've made it as you suggested. Jira is
https://issues.jboss.org/browse/GTNPORTAL-2340
I made it that getRequiresLifeCycle returns true for:
PortalRequestHandler, LegacyRequestHandler
and returns false for: DefaultRequestHandler,
StaticResourceRequestHandler, DownloadHandler, UploadHandler
Adding new method will require changes for other handlers in other eXo
components. At least for EPP-SP I am seeing two additional handlers
mapped with names "robots" and "sitemap". Should I create JIRA for you
in some eXo project to cover it?
>> Any other suggestions for this?
>>
>> Marek
>>
>> _______________________________________________
>> gatein-dev mailing list
>> gatein-dev(a)lists.jboss.org
>>
https://lists.jboss.org/mailman/listinfo/gatein-dev