[xwiki-devs] Introduce new tempresource action

Hi, Part I ===== I've started implementing a Ditaa Macro over the weekend (http://ditaa.sourceforge.net/ ) but we need an Action to return the Ditaa-generated image file. For the chart macro we're using the charting action but I think we can make this generic and instead introduce a tmp (or temp or tmpresource or ...) action instead that would return any resource located in the xwiki temporary directory. For ex: /xwiki/bin/tmp/SomeResource would return SomeResource found in container.getApplicationContext().getTemporaryDirectory(). Part II ===== The only thing to be careful about is to not be able to read what's for another user and for which you don't have access to see it. For example an image generated by the chart macro for a page for which the user doesn't have view rights. This can be partially solved by ensuring that file names include a generated token. However the pb is that this token cannot be unique since, for ex, generated image need to be shared to anyone having the rights to view a page. <brainstomring mode> A solution I see would be to include the "rights" to check + the full page name in the URL, in addition to the resource. For example: /xwiki/bin/tmp/view/wiki:Space.Page/SomeResource A more generic solution would be to add a notion of Check Handler, i.e. code that would perform the check. For example in the previous solution it's not possible to check for 2 permissions, nor any complex scheme. This would mean something like: /xwiki/bin/tmp/<check handler name>/<resource name>?<check params> Ex: /xwiki/bin/tmp/simple/SomeResource? checkPermission="view"&checkDocument="wiki:Space.Page" Implementation: A component with a role hint of "simple" would be looked-up and the check logic delegated to it. However someone could use a some check for a resource that wasn't meant to be used for that resource. Thus the check and its params should probably instead be included in the resource name with some algorithm instead. Thus the solution maybe to have a high level API to create a resource name and that API would take a Check Handler hint + some arbitrary params and that API would generate a resource name with these added. For ex something like:: "SomeResource-simple-view-wiki:Space.Page" (or any other format). Another solution would be to follow a completely different direction and for example to introduce a new XDOM representation for a TMP- image, i.e. in addition to URLImage and DocumentImage, to add a TemporaryImage implementation. </brainstomring mode> WDYT about these 2 ideas and especially about Part I since I would need that sooner rather than later to implement the Ditaa macro, and Part II is already a problem today. Thanks -Vincent