Gatekeeper

• Users & Groups
  • Users
    • Password hashing
    • User repository
  • Groups
    • Group repository
• Authentication
• Authorization
  • Policies
  • Authorizing
• Database schema
  • MySQL
  • PostgreSQL
  • SQLite
• Adapters

The gatekeeper library makes it easy to implement both authentication and authorization in your applications.

Users and groups

We'll need users and maybe a group or two before we can start authenticating and authorizing so we'll start with explaining how to create and manage them.

Users

The createUser method allows you to create a new user. A user object is returned upon successful creation.

$user = $this->gatekeeper->createUser('foo@example.org', 'username', 'password');

// You can also choose to activate the user upon creation

$user = $this->gatekeeper->createUser('foo@example.org', 'username', 'password', true);

The gatekeeper user objects are ORM models that come with a many to many relation to the group model and the group model has a many to many relation back to the user model.

If you chose to create a user without activating it then you'll probably want to implement email validation using the action token which can be retrieved from the user object using the getActionToken method.

$token = $user->getActionToken();

// Send the user an email with an activation link containing the token

...

To activate the user you'll have to use the activateUser method. The method will return true on success and false if the activation fails. The method will also automatically generate a new action token for the user upon successful activation.

$activated = $this->gatekeeper->activateUser($token);

Action tokens can also be used to validate "forgot password" requests (etc...) and should always be regenerated upon a successful action. This can be done using the generateActionToken method.

$user->generateActionToken();

$user->save();

Users have a second type of token called "access tokens" that are used by gatekeeper to identify users. The token can be retrieved using the getAccessToken method. New access token can be generated using the generateAccessToken method.

$user->generateAccessToken();

$user->save();

Note that generating a new access token will invalidate all active sessions and "remember me" cookies for the user in question. You can use the gatekeeper forceLogin method to log the user back in in the background to keep the experience seamless.

The user class also comes with the following methods in addition to the ones shown above:

† $group can be a group name, a group id or an array of group names or ids.
†† The method will also automatically rehash the password if necessary.

Note that all methods that change the sate of the user require you to call the save method to persist the changes.

Password hashing

User passwords are hashed using the hashing library. You can change the hashing algorithm or the default computing cost by reimplementing the getHasher method of the user class.

protected function getHasher(): HasherInterface
{
	return new Bcrypt(['cost' => 14]);
}

Passwords will automatically be rehashed using the new algorithm or computing cost upon successful login and when successfuly validated using the validatePassword method.

User repository

Users can be fetched from the database using the user repository.

$userRepository = $this->gatekeeper->getUserRepository();

The user repository class comes with the following methods:

Groups

The createGroup method allows you to create a new group. A group object is returned upon successful creation.

$group = $this->gatekeeper->createGroup('admin');

The gatekeeper group objects are ORM models that come with a many to many relation to the user model and the user model has a many to many relation back to the group model.

The group class comes with the following methods:

Group repository

Groups can be fetched from the database using the group repository.

$groupRepository = $this->gatekeeper->getGroupRepository();

The group repository class comes with the following methods:

Authentication

The login method will attempt to log a user in. The method returns true if the login is successful and a status code if not.

$successful = $this->gatekeeper->login($email, $password);

// You can also tell gatekeeper to set a "remember me" cookie

$successful = $this->gatekeeper->login($email, $password, true);

The possible status codes for failed logins are:

The forceLogin method allows you to login a user without a password. It will return true if the login is successful and a status code if not.

$successful = $this->gatekeeper->forceLogin($email);

// You can also tell gatekeeper to set a "remember me" cookie

$successful = $this->gatekeeper->forceLogin($email, true);

The basicAuth method can be useful when creating APIs or if you don't want to create a full login page. It will return true if the user is logged in and false if not.

if($this->gatekeeper->basicAuth() === false)
{
	return 'Authentication required.';
}

// Code here gets executed if the user is logged in

The username and password is sent with every subsequent request when using basic authentication so make sure to use HTTPS whenever possible!

The isGuest method returns false if the user is logged in and true if not.

$isGuest = $this->gatekeeper->isGuest();

The isLoggedIn method returns true of the user is logged in and false if not.

$isLoggedIn = $this->gatekeeper->isLoggedIn();

The getUser method will return a user object if the user is logged in and null if not.

$user = $this->gatekeeper->getUser();

The logout method will log out the user and delete the "remember me" cookie if it is set.

$this->gatekeeper->logout();

Authorization

The authorization component of the gatekeeper library allows you to check if a user is allowed to perform a specific action on a entity.

Policies

Authorization logic is defined in policy classes so that it can be reused anywhere in your application. In the example below we'll create a simple policy that authorizes the view, create, and edit actions on a article entity.

<?php

namespace app\policies;

use mako\gatekeeper\authorization\policies\Policy;
use mako\gatekeeper\entities\user\UserEntityInterface;

class ArticlePolicy extends Policy
{
	public function view(?UserEntityInterface $user, $entity): bool
	{
		return true;	
	}

	public function create(?UserEntityInterface $user, $entity): bool
	{
		if($user !== null && $user->isMemberOf('editors'))
		{
			return true;
		}

		return false;
	}

	public function edit(?UserEntityInterface $user, $entity): bool
	{
		if($user !== null && $user->getId() === $entity->user_id)
		{
			return true;
		}

		return false;
	}
}

The policy above extends the Policy class but you can choose to implement the PolicyInterface interface yourself if you want to implement the before method which lets you perform common checks in a single place.

public function before(?UserEntityInterface $user, string $action, $entity): ?bool
{
	if($user !== null && $user->isMemberOf('admins'))
	{
		return true;
	}

	return null;
}

Returning a boolean value will prevent further authorization checks while returning null ensures normal authorization.

Before we can use the policy we'll have to associate it with the corresponding entity. This is done in the app/config/gatekeeper.php configuration file. The array key is the class name of the entity and the value is the class name of the corresponding policy.

[
	Article::class => ArticlePolicy::class,
]

Authorizing

There are multiple ways of checking if a user is authorized to perform a certain action. The authorizer can method lets you authorize both guests and authenticated users.

if($this->authorizer->can($user, 'view', $article) === false)
{
	throw new ForbiddenException;
}

...

If you already know that you have an authenticated user then you can use the can method of the user class.

if($user->can('edit', $article) === false)
{
	throw new ForbiddenException;
}

...

And finally if your controller uses the AuthorizationTrait trait then you can use the authorize method that allows you to authorize both guests and authenticated users. It will automatically throw a ForbiddenException if the authorization fails.

$this->authorize('view', $article);

...

You'll not always be able to authorize actions on a entity instance so it also possible to pass the class name.

$this->authorize('create', Article::class);

...

Database schema

The gatekeeper library requires three database tables: a users table, a groups table, and a junction table that links the two of them together. Here are the schemas for MySQL, PostgreSQL and SQLite.

MySQL

CREATE TABLE `users` (
	`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
	`created_at` datetime NOT NULL,
	`updated_at` datetime NOT NULL,
	`ip` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
	`username` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
	`email` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
	`password` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
	`action_token` char(64) COLLATE utf8_unicode_ci DEFAULT '',
	`access_token` char(64) COLLATE utf8_unicode_ci DEFAULT '',
	`activated` tinyint(1) NOT NULL DEFAULT 0,
	`banned` tinyint(1) NOT NULL DEFAULT 0,
	`failed_attempts` int(11) NOT NULL DEFAULT '0',
	`last_fail_at` datetime DEFAULT NULL,
	`locked_until` datetime DEFAULT NULL,
	PRIMARY KEY (`id`),
	UNIQUE KEY `username` (`username`),
	UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `groups` (
	`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
	`created_at` datetime NOT NULL,
	`updated_at` datetime NOT NULL,
	`name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
	PRIMARY KEY (`id`),
	UNIQUE KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `groups_users` (
	`group_id` int(11) unsigned NOT NULL,
	`user_id` int(11) unsigned NOT NULL,
	UNIQUE KEY `group_user` (`group_id`,`user_id`),
	KEY `group_id` (`group_id`),
	KEY `user_id` (`user_id`),
	CONSTRAINT `groups`
		FOREIGN KEY (`group_id`)
		REFERENCES `groups` (`id`)
		ON DELETE CASCADE ON UPDATE NO ACTION,
	CONSTRAINT `users`
		FOREIGN KEY (`user_id`)
		REFERENCES `users` (`id`)
		ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

PostgreSQL

CREATE TABLE "users" (
	"id" SERIAL NOT NULL PRIMARY KEY,
	"created_at" TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
	"updated_at" TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
	"ip" VARCHAR(255) NOT NULL,
	"username" VARCHAR(255) NOT NULL UNIQUE,
	"email" VARCHAR(255) NOT NULL UNIQUE,
	"password" VARCHAR(255) NOT NULL,
	"action_token" CHAR(64) DEFAULT '',
	"access_token" CHAR(64) DEFAULT '',
	"activated" BOOLEAN NOT NULL DEFAULT FALSE,
	"banned" BOOLEAN NOT NULL DEFAULT FALSE,
	"failed_attempts" INTEGER NOT NULL DEFAULT 0,
	"last_fail_at" TIMESTAMP(0) WITHOUT TIME ZONE DEFAULT NULL,
	"locked_until" TIMESTAMP(0) WITHOUT TIME ZONE DEFAULT NULL
);

CREATE TABLE "groups" (
	"id" SERIAL NOT NULL PRIMARY KEY,
	"created_at" TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
	"updated_at" TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL,
	"name" VARCHAR(255) NOT NULL UNIQUE
);

CREATE TABLE "groups_users" (
	"group_id" INTEGER NOT NULL REFERENCES "groups" ON DELETE CASCADE,
	"user_id" INTEGER NOT NULL REFERENCES "users" ON DELETE CASCADE,
	UNIQUE ("group_id", "user_id")
);

CREATE INDEX "groups_users_group_id_idx" ON "groups_users" USING btree("group_id");

CREATE INDEX "groups_users_user_id_idx" ON "groups_users" USING btree("user_id");

SQLite

CREATE TABLE `users` (
	`id` INTEGER PRIMARY KEY AUTOINCREMENT,
	`created_at` TEXT NOT NULL,
	`updated_at` TEXT NOT NULL,
	`ip` TEXT(255) NOT NULL,
	`username` TEXT(255) NOT NULL,
	`email` TEXT(255) NOT NULL,
	`password` TEXT(255) NOT NULL,
	`action_token` TEXT(64) DEFAULT '',
	`access_token` TEXT(64) DEFAULT '',
	`activated` TINYINT NOT NULL DEFAULT 0,
	`banned` TINYINT NOT NULL DEFAULT 0,
	`failed_attempts` INTEGER NOT NULL DEFAULT 0,
	`last_fail_at` TEXT DEFAULT NULL,
	`locked_until` TEXT DEFAULT NULL,
	CONSTRAINT `username` UNIQUE (`username`),
	CONSTRAINT `email` UNIQUE (`email`)
);

CREATE TABLE `groups` (
	`id` INTEGER PRIMARY KEY AUTOINCREMENT,
	`created_at` TEXT NOT NULL,
	`updated_at` TEXT NOT NULL,
	`name` TEXT(255) NOT NULL,
	CONSTRAINT `name` UNIQUE (`name`)
);

CREATE TABLE `groups_users` (
	`group_id` INTEGER NOT NULL,
	`user_id` INTEGER NOT NULL,
	CONSTRAINT `group_user` UNIQUE (`group_id`, `user_id`),
	FOREIGN KEY (`group_id`)
		REFERENCES `groups` (`id`)
		ON DELETE CASCADE ON UPDATE NO ACTION,
	FOREIGN KEY (`user_id`)
		REFERENCES `users` (`id`)
		ON DELETE CASCADE ON UPDATE NO ACTION
);
CREATE INDEX `group_id` ON `groups_users` (`group_id`);
CREATE INDEX `user_id` ON `groups_users` (`user_id`);

Adapters

Gatekeeper comes with a session based adapter out of the box but you can implement your own custom adapters as well.

In the examples above we have chosen to use the gatekeeper class as a proxy to the default adapter. You can specify which adapter to use by calling the adapter method.

// Default adapter

$adapter = $this->gatekeeper->adapter();

// Custom adapter

$adapter = $this->gatekeeper->adapter('custom');

You can choose to replace the default adapter by creating a custom GatekeeperService or you can add additional adapters by registering them using the extend method.

// Register an instance

$this->gatekeeper->extend(new CustomAdapter);

// Register an adapter factory where the first array element
// is the adapter name while the second is the factory

$this->gatekeeper->extend(['custom', function() { return new CustomAdapter; }])

Note that all adapters must implement the AdapterInterface.

You can switch the default adapter at any time by using the useAsDefaultAdapter method.

$this->gatekeeper->useAsDefaultAdapter('custom');