Re: [Resteasy-developers] Interceptors

[Bill B. <bb...@re...>]

Not along at all...  Wanted to ping here first.  The injection is easy. 
   Already have utilities for that.

Ryan J. McDonough wrote:
> I like it! And I see where you're going with it. I think this will 
> provide a ton of flexibility in the app. I can see a lot of 
> opportunities for this kind of feature. How far along are with it?
> 
> Ryan-
> 
> 
> On Jul 9, 2008, at 6:53 PM, Bill Burke wrote:
> 
>> I'm currently prototyping some asynchronous jax-rs based on some of the
>> asynchronous talk in the Restful Web Services book.  At first I
>> implemented it in a non-abstract fashion.  Just brute force as I wanted
>> to see what patterns came up.  After this I realized that I needed some
>> form of interception to implement it.  (Mainly because of security).
>>
>> So, for interception here's some ideas:
>>
>> * Interceptors will be internal and not supported.  (I want us to write
>> a few before we even allow users to try them out).
>>
>> * interception would happen based on what additional annotation you
>> provided: @BeforeUnmarshalling, @AfterUnmarshalling, @BeforeMarshalling,
>> and @Aftermarshalling.
>>
>> * Interceptors will not be called for any subresource locator methods.
>>
>> * You would be able to use any JAX-RS annotation within the intercept
>> method.
>>
>> * It is an "around" pattern (like EJB's @AroundInvoke
>>
>> interface RequestContext
>> {
>>    void invokeNext();
>> }
>>
>> * You must inject and call invokeNext() on a RequestContext or no other
>> interceptors will be called, and the request will not be dispatched.
>>
>> * You will be able to inject the ResourceMethod object so you can get
>> preprocessed information about the method you are invoking on
>> (annotations, etc...)
>>
>>
>> So here's an example:
>>
>> @Provider
>> @Interceptor
>> public class CacheControlInterceptor
>> {
>>    @BeforeUnmarshalling(@Context HttpRequest request,
>>                         @Context HttpResponse response,
>>                         @Context RequestContext ctx)
>>    {
>>       if (isCached(request)) {
>>         writeCachedResponse(request, response);
>>         return; // don't continue with dispatching
>>       }
>>       return invokeNext();
>>    }
>>
>>
>>    @BeforeMarshalling
>>    public void writeCacheControlHeaders(@Context HttpResponse response
>>                                         @Context RequestContext ctx)
>>    {
>>       ... write some cache control headers...
>>    }
>>
>>    @AfterMarshalling
>>    public void grabBytesToMarshall(@Context HttpResponse response
>>                                    @Context RequestContext) {
>>    }
>> }
>>
>>
>>
>> -- 
>> Bill Burke
>> JBoss, a division of Red Hat
>> http://bill.burkecentral.com
>>
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> 

-- 
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com