grokcore.security 4.0

Setting up grokcore.security

This package is essentially set up like the grokcore.component package, please refer to its documentation for details. The additional ZCML lines you will need are:

<include package="grokcore.security" file="meta.zcml" />
<include package="grokcore.security" />

Put this somewhere near the top of your root ZCML file but below the line where you include grokcore.component’s configuration.

Defining permissions

In grokcore.component, various components are defined (and automatically registered) by subclassing from certain baseclasses. The same applies to defining permissions with grokcore.security as well:

import grokcore.security

class EditContent(grokcore.security.Permission):
    grokcore.security.name('mypkg.EditContent')

This defines a permission with the ID mypkg.EditContent. You must always specify this ID explicitly. In addition, you can also give the permission a human-readable title and description. This is useful when your application provides lists of permissions somewhere and you don’t want to bother users with deciphering the dotted IDs:

import grokcore.security

class EditContent(grokcore.security.Permission):
    grokcore.security.name('mypkg.EditContent')
    grokcore.security.title('Edit content')
    grokcore.security.description('Anyone who has this permission may '
                                  'modify content in the application.')

Defining checkers for components

grokcore.security provides some means for defining checkers for components:

• grokcore.security.require(permission) which can be used either as a class-level directive to set a permission for a whole component, or as a decorator to set a permission for a function or method.

• protect_getattr and protect_setattr, available from grokcore.security.util, which take a class, an attribute name and a permission as arguments and define Zope security checkers for getting or setting a particular attribute on instance of said class.

With these, you can build grokkers for components that need security declarations. For instance, the grokcore.view package uses them to define a grokker that makes security declarations for views:

class ViewSecurityGrokker(martian.ClassGrokker):
    martian.component(grokcore.view.View)
    martian.directive(grokcore.security.require, name='permission')

    def execute(self, factory, config, permission, **kw):
        for method_name in zope.publisher.interfaces.browser.IBrowserPage:
            config.action(
                discriminator=('protectName', factory, method_name),
                callable=grokcore.security.util.protect_getattr,
                args=(factory, method_name, permission),
                )
        return True

With such a grokker, it is possible to protect views like so:

class Edit(grokcore.view.View):
    grokcore.security.require(EditContent)

Note how we can simply pass a permission class to the require directive. Alternatively, you can pass the permission ID:

class Edit(grokcore.view.View):
    grokcore.security.require('mypkg.EditContent')

If you wanted to be able to define permissions for individual class methods rather than the whole class, you would simply base your grokker on martian.MethodGrokker rather than ClassGrokker. The actual mechanics of defining a checker are the same.

Please note that grokcore.security does not yet provide directives that allow you to specify permissions for simple attribute access (read and write).

API overview

Permission

Base class for defining permissions. Use the name directive to define the mandatory permission ID. Optionally use the title and description directives to give the permission human-readable information.

Public

Special permission that can be referred to whenever a component should not be protected by a permission at all (public access).

require(permission_class_or_id)

declares that the use of a particular component (when used as a class-level directive) or a method (when used as a method decorator) requires a certain permission. The argument can either be a permission class (subclass of Permission) or a permission ID.

In addition, the grokcore.security package exposes the grokcore.component API.

Changes