How to identify the rule or permission name with in predicator?

[Ramana Kumar K]

Hi, Is it possible to get rule or permission name within predicator function? Becuase, I have written a generic function which checks and provides True or False. However, it needs the permission name.

Is there any solution?

[dfunckt]

There is no good way currently, though I did play around a bit a while ago to refactor rules in order to support this but it turns out it’s a pretty invasive change I’m not sure I want to pursue. More context and link to the branch if you want to play with it here: #44

Closing as a duplicate of that issue, feel free to continue the discussion there

[Ryan P Kilby]

It's not ideal, but you might be able to use partials to bind the permission name to your function. e.g.,

def generic(obj, target, *, perm_name):
    ...

can_view_book = predicate(partial(generic, perm_name='can_view_book'))
can_edit_book = predicate(partial(generic, perm_name='can_edit_book'))
# etc...

[Ramana Kumar K]

Thanks @rpkilby for the quick suggestion.

I am getting the following error as * is not allowed.

def has_permission(user, perm_obj, *,  perm_name):
                                    ^

SyntaxError: invalid syntax

if I remove the * argument, I am getting error ...

assert num_args <= 2, 'Incompatible predicate.'

AssertionError: Incompatible predicate.

Kindly advice.

[Ryan P Kilby]

Hm. rules might be checking the signature. You could also just wrap in another function.

def generic(obj, target, perm_name):
    ...

@predicate
def can_view_book(obj, target): 
    return generic(obj, target, perm_name='can_view_book')

[Ramana Kumar K]

So, I need to create as many wrapper functions as I have the tags. So there is no point in generic function.

So currently, I am passing a string to predicate in my view as fn. i.e

@permission_required('perm_check', fn='Executes_key2')
def progress_dashboard(emp):

here, perm_check is rule permission. "Exceutes_key2' is key which is getting passed to predicate to identify what permissions to check.