Ah,

So for example, you could subtype cr_revision or whatever to determine the type. But of course, there are no permissions on object_types.

What I have done in the past is create a special object per "type" of thing I need to permission and check permissions on that object. of course that is a pain if you want to do that on top of file storage, which is not aware of these types.

Well then again, to define the type you'd need to map it somehow so you need a mapping table somewhere. This could be categories.

That seems like a good compromise, but you still have to check permissions on the category the object is mapped to.

I imagine you want custom package_id/type permission mappings, so that a user or group would have permission for certain types within an instance of file storage.

Even if you make object types objects and applied permissions on those, it would apply overall, not within a certain package instance.

I have thought about making xofs or something like that copying the code from xowiki, but what stopped me was the fact that I would need to create a subtype of xofs::file on the fly as the adding of file or project "types" needs to be something the end user should be able to configure. Which would mean to create the subtype on the fly (no problem) and keep it persistent, and here I am not sure if I can just create the subtype in the DB and it will work or do I need to write this into the filesystem as well as I need to do with classes?

On a related note: Excellent that you work on the xowiki-faq. This will help a lot of users!

malte, there is no need to copy code from xowiki, one can use xowiki and reuse it like e.g. in the s5 package. There is also no need to create a high number of subtypes. Here are two approaches, the second one requires no new subtype at all.

1) One can subclass xowiki::File to e.g. XFile, add an "security label" as in mandatory access control systems as an additional attribute (security_label). If this label is an acs-object, one can define a policy rule like

Class XFile -array set require_permission {

  download {{security_label read}}

}

one can define as security labels acs-objects "public", "internal use", "confidential", "top secret" and give the users rights to these (acs) objects (e.g. via groups). When an XFile is created, the security labels are associated with the files. With the policy definition above, you should be done.

2) maybe less efficient, but less programming work, using categories as security labels.

xotcl-core defines a couple of "privileges" such as "swa", "login", "creator" which are not necessarily based on acs_permissions. These privileges are defined as single words in the policy rules. One can define custom privileges as well, which are methods with names like "privilege=SOMETHING".

You can define a category tree named "security labels", map the tree to the instance, require the user to provide categories like "public" .. "top secret" for the files.
You can define such a privilege method (e.g. privilege=label), and check in this method, whether the object has such a label. Finally check, if the user has clearance for this label. Since categories are already acs-objcets, rights could be provided for the category objects.

There is an example for a custom privilege rule in generic-procs (privilege=creator, which we used for the conference registration).