[SLING-1003] Integration of 3rd party servlet filters problematic

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Engine 2.0.4
• Fix Version/s: Engine 2.1.0
• Component/s: Engine
• Environment: Windows Vista, ; java version "1.6.0_13"; Java(TM) SE Runtime Environment (build 1.6.0_13-b03); Java HotSpot(TM) Client VM (build 11.3-b02, mixed mode, sharing)
• Assignee: Felix Meschberger
• Reporter: Christian Sprecher
• Created: 12/Jun/09 05:21
• Updated: 30/Aug/10 12:48
• Resolved: 15/Oct/09 14:08

Description

There is a problem within the chain handling: the 3rd party filter uses it's own wrapper for requests and response, and supplies it to the chain in the chain.doFilter() call. This leads to a ClassCastException on line 54 of AbstractSlingFilterChain:
...
RequestProgressTracker tracker = ((SlingHttpServletRequest) request).getRequestProgressTracker();
...

I am not sure if this cast is valid in the context of a filter chain. On the other hand I am not sure wether such a use case (filter that manipulates request and response) has a chance to run in Sling.

==> Please note that this servlet filter needs to run as early as possible in the filter chain

java.lang.ClassCastException: org.webcastellum.RequestWrapper cannot be cast to
org.apache.sling.api.SlingHttpServletRequest
at org.apache.sling.engine.impl.filter.AbstractSlingFilterChain.doFilter
(AbstractSlingFilterChain.java:54)
at org.webcastellum.WebCastellumFilter.internalDoFilter(WebCastellumFilt
er.java:2610)
at org.webcastellum.WebCastellumFilter.doFilter(WebCastellumFilter.java:
1710)