Details
Major Description
As of SLING-319 (SVN Rev. 636296) functionality was removed from the ResourceResolver implementation to signal that a resource exists but is not accessible. The goal was to align the behaviour of the resource resolver to the behaviour of JCR which does not distinguish between non-existing and non-accessible resource.
The consequence of this change is that the application cannot properly distinguish between the two states and has to resort to guessing about the situation and also guess as to whether different authentication should be requested or not.
Over time it became evident, that this behaviour makes the application too complex. Unfortunately, we cannot "fix" JCR to distinguish between non-existing and non-accessible. So we have to reinsert the checks removed in Rev. 636296 to be able to distinguish.
The exception conveyed will be defined in the Sling API and extend from SlingException, thus being a RuntimeException. The SlingMainServlet will catch this exception (as it catches the NonExistingResource exception) and calls HttpServletResponse.sendError(403) (FORBIDDEN). An error handler script for 403/FORBIDDEN can then decide on whether to request authentication or send 403 or hide the fact that a resource would exist and in fact send a 404/NOT FOUND code.
The change of the ResourceResolver is compatible with previous versions because the new exception thrown extends SlingException and the methods are already documented to potentially throw SlingException. In this respect it is just a refinement.
Changes required:
- Add new exception conveying denied access situation providing the path to the resource to which access was denied
- Add JavaDoc to ResourceResolver API to document potential new access denial exception
- Add support to SlingMainServlet to convert the exception into a 403/FORBIDDEN status
- Reimplement the functionlity removed in Rev. 636296
The version of the o.a.s.resource package will be raised to 2.1 since this change requires adaptions in the implementation. The bundle version of the jcr/resource bundle might also be increased to the next minor version to indicate this new functionality.
NOTE: Downstream applications currently handling 404/NOT FOUND to try to distinguish between non-existing and non-accessible must be adapted.