Authorization

Roles

UserFrosting implements an extended version of role-based access control, which allows for very fine-grained control over user permissions. Every user can have zero or more roles, and every role can have zero or more permissions. Users' effective permissions are determined through their roles.

For example, consider the following roles, and their associated permissions:

• Member
  • Can update their own account info
  • Can post a new message
  • Can delete their own messages
• Site Administrator
  • Can update any account's info
  • Can delete any account's messages

If Alice has the Member role, she will be able to update her account info, post new messages, and delete her own messages. If she had the Site Administrator role as well, she would gain the ability to update other users' accounts and delete their messages, in addition to the permissions that she has from her Member role.

Permissions

A permission is a rule that associates an action with a set of conditions under which that action can be performed. These are defined in the permissions database table. For example:

• slug is a string that you select to represent this permission in your code. If your slug is uri_user, then in your code you can call $authorizer->checkAccess($currentUser, 'uri_user') to determine if the current user has this permission. You can define multiple permissions on the same slug. As long as a user passes at least one permission on that slug, they will be granted access.
• conditions allows you to set constraints on this permission. For example, you might want to create a permission that allows access on uri_user, but only for users in a particular group. A boolean expression consisting of access condition callbacks can be used to construct your condition.
• name is a human-readable label for the permission, which can be used to easily identify it in the role management interface.
• description is a text description for the permission, allowing you to describe the purpose of the permission in human-readable terms.

Performing access checks

In your code, access is controlled through the use of access checks on permission slugs. Often times, you will want to perform these checks in your controller methods, and throw a ForbiddenException if the current user fails the check.

This can be done by calling the checkAccess method of the authorizer service. For example:

/** @var UserFrosting\Sprinkle\Account\Authorize\AuthorizationManager */
$authorizer = $this->ci->authorizer;

/** @var UserFrosting\Sprinkle\Account\Model\User $currentUser */
$currentUser = $this->ci->currentUser;

if (!$authorizer->checkAccess($currentUser, 'uri_users')) {
    throw new ForbiddenException();
}

If the current user does not have any permissions for the slug uri_users, then the controller method will be aborted and a ForbiddenException will be thrown. By default, the ForbiddenExceptionHandler will catch this exception and generate a "404 Not Found" response.

You can, of course, use checkAccess to control the behavior of your controller methods in other ways. For example, you might build a data API that is available to the public, but that returns more specialized information to authorized users:

if ($authorizer->checkAccess($currentUser, 'uri_owls')) {
    return $response->withJson($secretOwls);
} else {
    return $response->withJson($publicOwls);
}

Access conditions

Access conditions are PHP expressions composed of callbacks and boolean operators. These expressions must return a boolean value when evaluated. When UserFrosting checks a permission for a given user, it will evaluate the condition expression, passing in any additional data from the final argument of checkAccess, and grant the permission only if the expression evaluates to true. For example, suppose the current user has the permission:

In your code, if you call:

$requestedActivity = Activity::find($requestedActivityId);

if (!$authorizer->checkAccess($currentUser, 'uri_activity', [
    'activity' => $requestedActivity
])) {
    throw new ForbiddenException();
}

Then, the equals_num condition will be used to compare the current user's id with the user_id associated with the requested activity (passed in as the activity key). If they match, then the condition evaluates to true and the user is granted access. You can use boolean operators to built arbitrarily complex conditions:

!has_role(user.id,2) && !is_master(user.id)

Callbacks

UserFrosting ships with a number of predefined access condition callbacks, which are defined in sprinkles/account/src/ServicesProvider/ServicesProvider.php:

Custom callbacks

To add your own access condition callbacks, simply extend the authorizer service in your Sprinkle's ServicesProvider:

$container->extend('authorizer', function ($authorizer, $c) {
    $authorizer->addCallback('in_organization',
        /**
         * Check if the specified user (by id) is in a particular organization.
         *
         * @param int $user_id the id of the user.
         * @param int $organization_id the id of the organization.
         * @return bool true if the user is in the organization, false otherwise.
         */
        function ($user_id, $organization_id) use ($c) {
           $user = $c->classMapper->staticMethod('user', 'find', $user_id);
           return ($user->organization_id == $organization_id);
        }
    );

    return $authorizer;
});

Creating new permissions

You may notice that while roles can be created and modified through the administrative interface, permissions cannot. This is because permissions are intimately tied to your code and should not be modified during the course of daily site operation.

Think about it this way - for a permission to have any effect on your application at all, you must reference its slug somewhere in one of your controllers. This means that even if a user were to create a new permission through the web interface, it wouldn't make any difference until a developer were to implement some code that makes use of it.

Instead, you should think of permissions as hardcoded parts of your application that just happen to be stored in the database. Permissions can be added, removed, or modified using a database migration or a database seed.

Both methods can be used to create or manipulate permissions. Migrations are better suited to edit or remove existing permissions since they assure you permissions stays constant in time, but won't help you restore a permission if one gets deleted by accident, since a migration can only be run once. Seeds on the other hand can be run more than once, so they can be used to restore a deleted permission, but can't be relied on to edit a permission the same way you can with a migration, since a seed can be run in any order, and can't be automatically reverted.

With that in mind, it is recommended to use a seed to create permissions as it will make it easier to restore a deleted permission and the consistency can be checked manually. However, since both methods are valid and can be used depending on the developer choice, both are shown below.

Using a Seed

<?php
namespace UserFrosting\Sprinkle\Site\Database\Seeds;

use UserFrosting\Sprinkle\Account\Database\Models\Permission;
use UserFrosting\Sprinkle\Account\Database\Models\Role;
use UserFrosting\Sprinkle\Core\Database\Seeder\BaseSeed;

class CustomPermissions extends BaseSeed
{
    public function run()
    {
        // Add default permissions
        $permissions = [
            'uri_members' => new Permission([
                'slug' => 'uri_members',
                'name' => 'Member management page',
                'conditions' => 'always()',
                'description' => 'View a page containing a list of members.'
            ]),
            'uri_owls' => new Permission([
                'slug' => 'uri_owls',
                'name' => 'View owls',
                'conditions' => 'always()',
                'description' => 'View a full list of owls in the system.'
            ])
        ];

        foreach ($permissions as $id => $permission) {
            $slug = $permission->slug;
            $conditions = $permission->conditions;
            // Skip if a permission with the same slug and conditions has already been added
            if (!Permission::where('slug', $slug)->where('conditions', $conditions)->first()) {
                $permission->save();
            }
        }

        // Automatically add permissions to particular roles
        $roleAdmin = Role::where('slug', 'site-admin')->first();
        if ($roleAdmin) {
            $roleAdmin->permissions()->syncWithoutDetaching([
                $permissions['uri_members']->id,
                $permissions['uri_owls']->id
            ]);
        }
    }
}

Using a Migration

<?php
namespace UserFrosting\Sprinkle\Site\Database\Migrations\v100;

use UserFrosting\Sprinkle\Account\Database\Models\Permission;
use UserFrosting\Sprinkle\Account\Database\Models\Role;
use UserFrosting\System\Bakery\Migration;

class CustomPermissions extends Migration
{
    public static $dependencies = [
        '\UserFrosting\Sprinkle\Account\Database\Migrations\v400\PermissionsTable',
        '\UserFrosting\Sprinkle\Account\Database\Migrations\v400\RolesTable'
    ];

    public function up()
    {
        // Add default permissions
        $permissions = $this->getPermissions();

        foreach ($permissions as $id => $permission) {
            $slug = $permission->slug;
            $conditions = $permission->conditions;
            // Skip if a permission with the same slug and conditions has already been added
            if (!Permission::where('slug', $slug)->where('conditions', $conditions)->first()) {
                $permission->save();
            }
        }

        // Automatically add permissions to particular roles
        $roleAdmin = Role::where('slug', 'site-admin')->first();
        if ($roleAdmin) {
            $roleAdmin->permissions()->syncWithoutDetaching([
                $permissions['uri_members']->id,
                $permissions['uri_owls']->id
            ]);
        }
    }

    public function down()
    {
        foreach ($this->getPermissions() as $id => $permissionData) {
            $permission = Permission::where($permissionData)->first();
            $permission->delete();
        }
    }

    protected function getPermissions()
    {
        return [
            'uri_members' => new Permission([
                'slug' => 'uri_members',
                'name' => 'Member management page',
                'conditions' => 'always()',
                'description' => 'View a page containing a list of members.'
            ]),
            'uri_owls' => new Permission([
                'slug' => 'uri_owls',
                'name' => 'View owls',
                'conditions' => 'always()',
                'description' => 'View a full list of owls in the system.'
            ])
        ];
    }
}