sdwebserver/app/Controllers/Register.php

<?php

namespace App\Controllers;
use Gregwar\Captcha\CaptchaBuilder;
use Gregwar\Captcha\PhraseBuilder;
use App\Models\UsersModel;
use CodeIgniter\API\ResponseTrait;

class Register extends BaseController
{
    protected object $users;
	protected object $captcha;

	use ResponseTrait;

	public function __construct()
	{
		$this->captcha = new CaptchaBuilder;
		$this->users = new UsersModel;
	}

    public function index()
    {
		$this->captcha->build();
		$this->session->set('phrase', $this->captcha->getPhrase());
		echo get_header('Register');
		echo view('register', ['captcha' => $this->captcha->inline()]);
		echo get_footer(['register.js']);
    }

	public function newUser()
	{
		$data = $this->request->getVar();
		$response = [
			'ok'	=> false,
			'msg'	=> ''
		];

		// First verify the captcha
		if (
			$this->session->has('phrase') &&
			PhraseBuilder::comparePhrases($this->session->phrase, $data['phrase'])
		) {
            // Move the image
			$file = $this->request->getFile('imginput');
			if ($file)
			{
				// Verify is the file is correct and not, for example, a .exe renamed to .jpg
				$ext = $file->guessExtension();

				if ($ext != $file->getExtension()) $response['msg'] = 'The image is not valid';
				else
				{
					// Now we check if the user and/or email is already in use.
					if ($this->users->compUser($data['username'], $data['email']))
						$response['msg'] = 'Username and/or email is already in use';
					else $response = $this->users->addUser($data, $file);
				}
			}
        }
		else
		{
           $response['msg'] = 'Captcha not valid';
        }
		return $this->respond($response);
	}

	public function newCaptcha()
	{
		$this->captcha->build();
		$this->session->phrase = $this->captcha->getPhrase();	
		return $this->captcha->inline();
	}

	public function ok()
	{
		echo get_header('Register');
		echo view('register_ok');
		echo get_footer();
	}
}