grokcore.security 1.0

Grok-like configuration for Zope security components

This package provides basic elements for defining Zope permissions and security checkers without ZCML.

Contents

• Setting up grokcore.security

• Defining permissions

• Defining checkers for components

• Changes

Setting up grokcore.security

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

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

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).

Changes

1.0 (2008-08-03)

• Created grokcore.security in July 2008 by factoring security-related components, grokkers and directives out of Grok.