sling:alias

[Unmesh Joshi <un...@gmail.com>]

Hi,

I observed that when some resource is not found. (In my case, browser
was sending request for  favicon.ico), JcrResourceResolver iterates
through all the resource providers, loads resources and then tries to
match sling:alias property.
I have a custom resource provider which has to make a web service call
to build resource. So ends up making unnecessary service calls for
favicon.ico. I do not even know what the original request is
(favicon.ico), because I always get
same path for which the resource provider is registered.   I managed
to add a guard clause somehow, but I do not think its clean.

So a couple of questions.

1. What is difference between resource resolver and resource provider?
Is it recommended to implement custom resource resolver? Any samples?
2. Can sling:alias behavior be turned off?

Thanks,
Unmesh

Re: sling:alias

[Justin Edelson <ju...@justinedelson.com>]

On Tue, Dec 14, 2010 at 2:07 AM, Unmesh Joshi <un...@gmail.com> wrote:

> Hi,
>
> I observed that when some resource is not found. (In my case, browser
> was sending request for  favicon.ico), JcrResourceResolver iterates
> through all the resource providers, loads resources and then tries to
> match sling:alias property.
> I have a custom resource provider which has to make a web service call
> to build resource. So ends up making unnecessary service calls for
> favicon.ico. I do not even know what the original request is
> (favicon.ico), because I always get
> same path for which the resource provider is registered.   I managed
> to add a guard clause somehow, but I do not think its clean.
>
There was an issue raised about this on the dev list last month with respect
to user/group management. I think the outcome is that it this is a known
issue. However, it should be only touching ResourceProviders at the same
"level" as the resource being requested, so a simple suggestion would be to
register your custom ResourceProvider at a sub-path, not the top level


>
> So a couple of questions.
>
> 1. What is difference between resource resolver and resource provider?
>
The big difference is that a particular Sling instance should have exactly
one implementation of ResourceResolverFactory whereas there can be any
number of ResourceProvider services. In essence, the ResourceResolverFactory
is what makes the entire resource tree available to the application whereas
ResourceProviders allow for the resource tree to be composed of multiple
sources.


> Is it recommended to implement custom resource resolver? Any samples?
>
AFAIK, there is no publicly available ResourceResolverFactory other than the
JCR one.


> 2. Can sling:alias behavior be turned off?
>
I don't think so, but you could check the source to be sure. I think a
better solution would be to have ResourceProviders somehow able to say
"don't ask me about sling:alias", but I haven't thought that through.

Justin


>
> Thanks,
> Unmesh
>