Directus custom endpoint: Registration — Change what roles can be reigstered to in the `$roleMap` array, give it a friendly api-ready name, and a role id

auth.php

<?php // Version 3.0

use Directus\Application\Http\Request;
use Directus\Application\Http\Response;

class User {
    
    private $data;
    
    private $role;
    
    private $dbConnection;
    
    public function __construct() {
        /**
         * Defaults — These will be default values stored against the user.
         */
        $this->data = [
            'timezone' => 'Europe/London',
            'status' => 'active'
        ];
        
        $this->dbConnection = $dbConnection = \Directus\Application\Application::getInstance()->getContainer()->get('database');
    }
  
    public function setEmail($x) {
        isset($x) ? $this->data['email'] = $x : false;
        return $this;
    }
    
    public function setPassword($x) {
        $pw = \Directus\Authentication\Provider::hashPassword($x);
        isset($x) ? $this->data['password'] = $pw : false;
        return $this;
    }
  
    public function setFirstName($x) {
        isset($x) ? $this->data['first_name'] = $x : false;
        return $this;
    }
    
    public function setLastName($x) {
        isset($x) ? $this->data['last_name'] = $x : false;
        return $this;
    }
    
    public function setRole($x) {
        isset($x) ? $this->role = $x : false;
        return $this;
    }
    
    public function checkRoleExists($x) {
        // Query the database to see if the role exists before adding user to non-existant role.
        return true;
    }
    
    public function registerUser() {
        if(!$this->data['email'] || !$this->data['password']){
            throw new \Directus\Exception\Exception( 'Sorry! You didn\'t supply an email or password to register with.' );
        }

        $roleExists = $this->checkRoleExists($this->role);
        
        if(!$this->role || !$roleExists){
            throw new \Directus\Exception\Exception( 'Sorry! We couldn\'t register you to that role, please contact a system administrator.' );
        }
        
        $tblUsers = new \Zend\Db\TableGateway\TableGateway('directus_users', $this->dbConnection);
        $tblUserRoles = new \Zend\Db\TableGateway\TableGateway('directus_user_roles', $this->dbConnection);

        $tblUsers->insert($this->data);
        
        $userId = $tblUsers->getLastInsertValue();
        
        $tblUserRoles->insert([
            'user' => $userId,
            'role' => $this->role
        ]);
        
        $results = $tblUsers->select([
            'id' => $userId
        ]);
        
        $user = $results->current();
        
        return $user;
    }
    
}

return [
    // '/register' => [
    //     'method' => 'POST',
    //     'handler' => function (Request $request, Response $response) {
            
    //         $roleId = 3; // Member
            
    //         $POST = $request->getParsedBody();
            
    //         $user = new User();
            
    //         $user->setRole($roleId);
            
    //         $POST['first_name'] ? $user->setFirstName($POST['first_name']) : false;
            
    //         $POST['last_name'] ? $user->setLastName($POST['last_name']) : false;
            
    //         $POST['email'] ? $user->setEmail($POST['email']) : false;
            
    //         $POST['password'] ? $user->setPassword($POST['password']) : false;
            
    //         $data = $user->registerUser();
                   
    //         return $response->withJson([
    //             'data' => $data
    //         ]);
    //     }
    // ]
    '/register[/{role}]' => [
        'method' => 'POST',
        'handler' => function (Request $request, Response $response) {
            
            /**
             * 
             * Below is a map of roles that people can register to,
             * You can add a friendly name, and an ID, the ID must match the database.
             * I highly suggest never enabling admin... for obvious reasons.
             * 
             * Request (Post) : https://api.example.com/_/custom/auth/register/member
             * Response (JSON) : The created users data if successful.
             * 
             */
            $roleMap = [
                "member" => 3
            ];
            
            $POST = $request->getParsedBody();
            
            $role = $request->getAttribute('role');
            
            $roleId = $roleMap[$role];
            
            $user = new User();
            
            $user->setRole($roleId);
            
            $POST['first_name'] ? $user->setFirstName($POST['first_name']) : false;
            
            $POST['last_name'] ? $user->setLastName($POST['last_name']) : false;
            
            $POST['email'] ? $user->setEmail($POST['email']) : false;
            
            $POST['password'] ? $user->setPassword($POST['password']) : false;
            
            $data = $user->registerUser();
                   
            return $response->withJson([
                'data' => $data
            ]);
        }
    ]
];

Note: A tidier version of this was written by @mariorojas

https://gist.github.com/mariorojas/27e3328f3e19c70c3ef6bc337498b43e