User Permissions

Introduction

This class implements SilverStripe's permission system.

Usage

Permissions are defined on a group-by-group basis. To give a permission to a member, go to a group that contains them, and then select the permissions tab, and add that permission to the list.

The simple usage, Permission::check("PERM_CODE") will detect if the currently logged in member has the given permission. See the API docs for more options.

Group ACLs

Call Permission::check("MY_PERMISSION_CODE") to see if the current user has MY_PERMISSION_CODE.
MY_PERMISSION_CODE can be loaded into the Security admin on the appropriate group, using the "Permissions" tab.

PermissionProvider

[api:PermissionProvider] is an interface which lets you define a method providePermissions(). This method should return a map of permission code names with a human readable explanation of its purpose.

:::php
class Page_Controller implements PermissionProvider {
  public function init() {
    parent::init();
    if(!Permission::check("VIEW_SITE")) Security::permissionFailure();
  }

  public function providePermissions() {
    return array(
      "VIEW_SITE" => "Access the site",
    );
  }
}

This can then be used to add a dropdown for permission codes to the security panel. Permission::get_all_codes() will be a helper method that will call providePermissions() on every applicable class, and collate the resuls into a single dropdown.

Default use

By default, permissions are used in the following way:

The 'View' permission is checked when opening a page
The 'View' permissions is used on all default datafeeds:
- If not logged in, the 'View' permissions must be 'anyone logged in' for a page to be displayed in a menu
- If logged in, you must be allowed to view a page for it to be displayed in a menu

NOTE: Should the canView() method on SiteTree be updated to call Permission::check("SITETREE_VIEW", $this->ID)? Making this work well is a subtle business and should be discussed with a few developers.

Setting up permissions

By default, permissions are linked to groups. You define a many-many relationship called Can(permname), eg, "CanView". Please note that group permissions are more efficient, as SQL joins are used to filter data.
Alternatively, you can create a custom permission by defining a function called can(permname)

Using permissions

On an individual data record, $page->can("View", $member = null) and be called. If a member isn't passed, the currently logged in member is assumed.
On a request, $request->hasPermission("View", $member = null) can be called. See datamodel for information on request objects.

Special cases

ADMIN permissions

By default the config option admin_implies_all is true - this means that any user granted the ADMIN permission has all other permissions granted to them. This is a type of cascading of permissions that is hard coded into the permission system.

CMS access permissions

Access to the CMS has a couple of special cases where permission codes can imply other permissions.

1. Granting access to all CMS permissions

The CMS_ACCESS_LeftAndMain grants access to every single area of the CMS, without exception. Internally, this works by adding the CMS_ACCESS_LeftAndMain code to the set of accepted codes when a CMS_ACCESS_* permission is required. This works much like ADMIN permissions (see above)

2. Checking for any access to the CMS

You can check if a user has access to the CMS by simply performing a check against CMS_ACCESS.

:::php
if (Permission::checkMember($member, 'CMS_ACCESS')) {
	//user can access the CMS
}

Internally, this checks that the user has any of the defined CMS_ACCESS_* permissions.

API Documentation

[api:Permission]

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