Zope: getting acquired permission of a role on object

Question

I thought this must be easy but I really have troubles figuring it out: I'd like to check for an acquired permission of a role on an object.

I don't want to check for the actual user's roles or permissions, I just want to check i.e. if on an object Anonymous has the permission 'Access contents information'. This is easy if the permission is set on the object in question, but proves more difficult when the permission is acquired.

I tried this:

siteRoles = ('Anonymous', 'myRole1', 'myRole2', 'Manager')
permission = 'Access contents information'

rolesDictList = self.rolesOfPermission( permission )

roles = [roleDict['name'] for roleDict in rolesDictList if roleDict['selected']]

for i, role in enumerate(siteRoles):
    if role in roles:
        roleMin = i
        break

return roleMin

This does not work, because it does not give the acquired permissions.

My next idea was to walk through the parents upward until I find some permissions that are not acquired. But this would not really solve the problem, as it would ignore permissions that are set higher up in the hierarchy (ok, I could check for acquired and continue upward). Also there is an oddity: 'Manager' is always selected in rolesOfPermission. Why is this so?

Anyway, I presume there must be a simpler way to do this?

Answer 1

Simply use the rolesForPermissionOn() function:

from AccessControl.PermissionRole import rolesForPermissionOn

roles = rolesForPermissionOn(permission, context)

This returns a list of roles that have the specific permission for the given context. It'll walk the acquisition chain as needed.