Why am i getting this error when trying to send email for activation of new user account with phpmailer

Question

i am trying to understand why my subject method in index.php triggers an error of not being defined.i am using phpmailer 5.2.7 with php 7.2 and wampserver 3.1.7

//here is my extended class from phpmailer//

<?php
include('phpmailer.php');

class Mail extends PhpMailer
{

    // Set default variables for all new objects

    public $From     = 'xxxxxx@gmail.com';
    public $FromName =  MM;
    public $Host     = 'smtp.gmail.com';
    public $Mailer   = 'smtp';
    public $SMTPAuth =  true;
    public $Username = 'xxxxxxx@gmail.com';
    public $Password = 'xxxxxx';
    public $SMTPSecure = 'ssl';
    public $WordWrap = 75;



    public function subject($subject)
    {
        $this->Subject = $subject;
    }

    public function body($body)
    {
        $this->Body = $body;
    }

    public function send()
    {
        $this->AltBody = strip_tags(stripslashes($this->Body))."\n\n";
        $this->AltBody = str_replace("&nbsp;", "\n\n", $this->AltBody);
        return parent::send();
    }
}

and here is part of my index page where i have defined my variables

$to = $_POST['email'];
            $subject = "Registration Confirmation";
            $body = "<p>Thank you for registering at demo site.</p>
            <p>To activate your account, please click on this link: <a href='".DIR."activate.php?x=$id&y=$activasion'>".DIR."activate.php?x=$id&y=$activasion</a></p>
            <p>Regards Site Admin</p>";

            $mail = new PHPMailer(true);
            $mail->setFrom(SITEEMAIL);
            $mail->addAddress($to);
            $mail->subject($subject);
            $mail->body($body);
            $mail->send();

            //redirect to index page
            header('Location: index.php?action=joined');
            exit;

Answer 1

Firstly, why are you using a version of PHPMailer that's literally years out of date? Get the latest , which has new features, fixed bugs, and fewer security holes. While you're upgrading, consider switching to using composer to manage your dependencies.

The problem you're having is quite straightforward: you have created a subclass that adds the subject() method, but the instance you've created in your script is of the original PHPMailer class, not your subclass. Do this instead:

$mail = new Mail(true);

Naming your class with a very generic "Mail" name is very likely to bring you an unexpected lesson on why namespacing is a good idea, so I'd recommend adding a namespace for your app to avoid name clashes.

While it's a good idea to subclass like this to set default values easily, it's also inviting you to check in credentials to your source repo, which is usually a bad idea. Better to use your child class to read those values from an environment file ("dot env") using a package like this .