AMPmailPHPMailer.php

<?php
/* CUSTOM MAILER FOR AMP EMAILS USING PHPMAILER */

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

include 'phpmailer/vendor/autoload.php';

class AMPmailPHPMailer extends PHPMailer
{
    public $AMPBody = '';
    /**
     * AMPmailPHPMailer constructor.
     *
     * @param bool|null $exceptions
     * @param string    $body A default HTML message body
     */

    public function __construct($exceptions, $body = '')
    {
        parent::__construct($exceptions);
        $this->SMTPDebug = SMTP::DEBUG_SERVER;
        // $mail->SMTPDebug = 1;

        $this->isSMTP();
        
        $this->Host 		= ''; //SMTP server host 
        $this->Port     	= ''; //SMTP Port number
        $this->SMTPAuth   = true; //Enable SMTP authentication
        $this->Username   = '';   //SMTP username
        $this->Password   = '';   //SMTP password

        $this->setFrom('admin@example.com', 'Mailer');
        
        $this->addReplyTo('noreply@example.com', 'No reply');

        $this->Debugoutput = static function ($str, $level) {
            //echo "Debug level $level; message: $str\n";
        };
    }

    public function send()
    {
        try {
            if (!$this->preSend()) {
                return false;
            }

            return parent::postSend();
        } catch (Exception $exc) {
            $this->mailHeader = '';
            $this->setError($exc->getMessage());
            if ($this->exceptions) {
                throw $exc;
            }
            return false;
        }
    }

    public function createBody()
    {
        $body = '';
        //Create unique IDs and preset boundaries
        $this->uniqueid = $this->generateId();
        $this->boundary[1] = 'b1_' . $this->uniqueid;
        $this->boundary[2] = 'b2_' . $this->uniqueid;
        $this->boundary[3] = 'b3_' . $this->uniqueid;

        if ($this->sign_key_file) {
            $body .= $this->getMailMIME() . static::$LE;
        }

        $this->setWordWrap();

        $bodyEncoding = $this->Encoding;
        $bodyCharSet = $this->CharSet;
        //Can we do a 7-bit downgrade?
        if (static::ENCODING_8BIT === $bodyEncoding && !$this->has8bitChars($this->Body)) {
            $bodyEncoding = static::ENCODING_7BIT;
            //All ISO 8859, Windows codepage and UTF-8 charsets are ascii compatible up to 7-bit
            $bodyCharSet = static::CHARSET_ASCII;
        }
        //If lines are too long, and we're not already using an encoding that will shorten them,
        //change to quoted-printable transfer encoding for the body part only
        if (static::ENCODING_BASE64 !== $this->Encoding && static::hasLineLongerThanMax($this->Body)) {
            $bodyEncoding = static::ENCODING_QUOTED_PRINTABLE;
        }

        $altBodyEncoding = $this->Encoding;
        $altBodyCharSet = $this->CharSet;
        //Can we do a 7-bit downgrade?
        if (static::ENCODING_8BIT === $altBodyEncoding && !$this->has8bitChars($this->AltBody)) {
            $altBodyEncoding = static::ENCODING_7BIT;
            //All ISO 8859, Windows codepage and UTF-8 charsets are ascii compatible up to 7-bit
            $altBodyCharSet = static::CHARSET_ASCII;
        }
        //If lines are too long, and we're not already using an encoding that will shorten them,
        //change to quoted-printable transfer encoding for the alt body part only
        if (static::ENCODING_BASE64 !== $altBodyEncoding && static::hasLineLongerThanMax($this->AltBody)) {
            $altBodyEncoding = static::ENCODING_QUOTED_PRINTABLE;
        }
        //Use this as a preamble in all multipart message types
        $mimepre = 'This is a multi-part message in MIME format.' . static::$LE . static::$LE;
        switch ($this->message_type) {
            case 'inline':
                $body .= $mimepre;
                $body .= $this->getBoundary($this->boundary[1], $bodyCharSet, '', $bodyEncoding);
                $body .= $this->encodeString($this->Body, $bodyEncoding);
                $body .= static::$LE;
                $body .= $this->attachAll('inline', $this->boundary[1]);
                break;
            case 'attach':
                $body .= $mimepre;
                $body .= $this->getBoundary($this->boundary[1], $bodyCharSet, '', $bodyEncoding);
                $body .= $this->encodeString($this->Body, $bodyEncoding);
                $body .= static::$LE;
                $body .= $this->attachAll('attachment', $this->boundary[1]);
                break;
            case 'inline_attach':
                $body .= $mimepre;
                $body .= $this->textLine('--' . $this->boundary[1]);
                $body .= $this->headerLine('Content-Type', static::CONTENT_TYPE_MULTIPART_RELATED . ';');
                $body .= $this->textLine(' boundary="' . $this->boundary[2] . '";');
                $body .= $this->textLine(' type="' . static::CONTENT_TYPE_TEXT_HTML . '"');
                $body .= static::$LE;
                $body .= $this->getBoundary($this->boundary[2], $bodyCharSet, '', $bodyEncoding);
                $body .= $this->encodeString($this->Body, $bodyEncoding);
                $body .= static::$LE;
                $body .= $this->attachAll('inline', $this->boundary[2]);
                $body .= static::$LE;
                $body .= $this->attachAll('attachment', $this->boundary[1]);
                break;
            case 'alt':
                $body .= $mimepre;
                $body .= $this->getBoundary(
                    $this->boundary[1],
                    $altBodyCharSet,
                    static::CONTENT_TYPE_PLAINTEXT,
                    $altBodyEncoding
                );
                $body .= $this->encodeString($this->AltBody, $altBodyEncoding);
                $body .= static::$LE;

                $body .= $this->getBoundary(
                    $this->boundary[1],
                    $bodyCharSet,
                    static::CONTENT_TYPE_TEXT_HTML,
                    $bodyEncoding
                );
                $body .= $this->encodeString($this->Body, $bodyEncoding);
                $body .= static::$LE;

                $body .= $this->getBoundary(
                    $this->boundary[1],
                    'utf-8',
                    'text/x-amp-html',
                    $bodyEncoding
                );
                $body .= $this->encodeString($this->AMPBody, $bodyEncoding);
                $body .= static::$LE;

                if (!empty($this->Ical)) {
                    $method = static::ICAL_METHOD_REQUEST;
                    foreach (static::$IcalMethods as $imethod) {
                        if (stripos($this->Ical, 'METHOD:' . $imethod) !== false) {
                            $method = $imethod;
                            break;
                        }
                    }
                    $body .= $this->getBoundary(
                        $this->boundary[1],
                        '',
                        static::CONTENT_TYPE_TEXT_CALENDAR . '; method=' . $method,
                        ''
                    );
                    $body .= $this->encodeString($this->Ical, $this->Encoding);
                    $body .= static::$LE;
                }
                $body .= $this->endBoundary($this->boundary[1]);
                break;
            case 'alt_inline':
                $body .= $mimepre;
                $body .= $this->getBoundary(
                    $this->boundary[1],
                    $altBodyCharSet,
                    static::CONTENT_TYPE_PLAINTEXT,
                    $altBodyEncoding
                );
                $body .= $this->encodeString($this->AltBody, $altBodyEncoding);
                $body .= static::$LE;
                $body .= $this->textLine('--' . $this->boundary[1]);
                $body .= $this->headerLine('Content-Type', static::CONTENT_TYPE_MULTIPART_RELATED . ';');
                $body .= $this->textLine(' boundary="' . $this->boundary[2] . '";');
                $body .= $this->textLine(' type="' . static::CONTENT_TYPE_TEXT_HTML . '"');
                $body .= static::$LE;
                $body .= $this->getBoundary(
                    $this->boundary[2],
                    $bodyCharSet,
                    static::CONTENT_TYPE_TEXT_HTML,
                    $bodyEncoding
                );
                $body .= $this->encodeString($this->Body, $bodyEncoding);
                $body .= static::$LE;
                $body .= $this->attachAll('inline', $this->boundary[2]);
                $body .= static::$LE;
                $body .= $this->endBoundary($this->boundary[1]);
                break;
            case 'alt_attach':
                $body .= $mimepre;
                $body .= $this->textLine('--' . $this->boundary[1]);
                $body .= $this->headerLine('Content-Type', static::CONTENT_TYPE_MULTIPART_ALTERNATIVE . ';');
                $body .= $this->textLine(' boundary="' . $this->boundary[2] . '"');
                $body .= static::$LE;
                $body .= $this->getBoundary(
                    $this->boundary[2],
                    $altBodyCharSet,
                    static::CONTENT_TYPE_PLAINTEXT,
                    $altBodyEncoding
                );
                $body .= $this->encodeString($this->AltBody, $altBodyEncoding);
                $body .= static::$LE;
                $body .= $this->getBoundary(
                    $this->boundary[2],
                    $bodyCharSet,
                    static::CONTENT_TYPE_TEXT_HTML,
                    $bodyEncoding
                );
                $body .= $this->encodeString($this->Body, $bodyEncoding);
                $body .= static::$LE;
                if (!empty($this->Ical)) {
                    $method = static::ICAL_METHOD_REQUEST;
                    foreach (static::$IcalMethods as $imethod) {
                        if (stripos($this->Ical, 'METHOD:' . $imethod) !== false) {
                            $method = $imethod;
                            break;
                        }
                    }
                    $body .= $this->getBoundary(
                        $this->boundary[2],
                        '',
                        static::CONTENT_TYPE_TEXT_CALENDAR . '; method=' . $method,
                        ''
                    );
                    $body .= $this->encodeString($this->Ical, $this->Encoding);
                }
                $body .= $this->endBoundary($this->boundary[2]);
                $body .= static::$LE;
                $body .= $this->attachAll('attachment', $this->boundary[1]);
                break;
            case 'alt_inline_attach':
                $body .= $mimepre;
                $body .= $this->textLine('--' . $this->boundary[1]);
                $body .= $this->headerLine('Content-Type', static::CONTENT_TYPE_MULTIPART_ALTERNATIVE . ';');
                $body .= $this->textLine(' boundary="' . $this->boundary[2] . '"');
                $body .= static::$LE;
                $body .= $this->getBoundary(
                    $this->boundary[2],
                    $altBodyCharSet,
                    static::CONTENT_TYPE_PLAINTEXT,
                    $altBodyEncoding
                );
                $body .= $this->encodeString($this->AltBody, $altBodyEncoding);
                $body .= static::$LE;
                $body .= $this->textLine('--' . $this->boundary[2]);
                $body .= $this->headerLine('Content-Type', static::CONTENT_TYPE_MULTIPART_RELATED . ';');
                $body .= $this->textLine(' boundary="' . $this->boundary[3] . '";');
                $body .= $this->textLine(' type="' . static::CONTENT_TYPE_TEXT_HTML . '"');
                $body .= static::$LE;
                $body .= $this->getBoundary(
                    $this->boundary[3],
                    $bodyCharSet,
                    static::CONTENT_TYPE_TEXT_HTML,
                    $bodyEncoding
                );
                $body .= $this->encodeString($this->Body, $bodyEncoding);
                $body .= static::$LE;
                $body .= $this->attachAll('inline', $this->boundary[3]);
                $body .= static::$LE;
                $body .= $this->endBoundary($this->boundary[2]);
                $body .= static::$LE;
                $body .= $this->attachAll('attachment', $this->boundary[1]);
                break;
            default:
                //Catch case 'plain' and case '', applies to simple `text/plain` and `text/html` body content types
                //Reset the `Encoding` property in case we changed it for line length reasons
                $this->Encoding = $bodyEncoding;
                $body .= $this->encodeString($this->Body, $this->Encoding);
                break;
        }

        if ($this->isError()) {
            $body = '';
            if ($this->exceptions) {
                throw new Exception($this->lang('empty_message'), self::STOP_CRITICAL);
            }
        } elseif ($this->sign_key_file) {
            try {
                if (!defined('PKCS7_TEXT')) {
                    throw new Exception($this->lang('extension_missing') . 'openssl');
                }

                $file = tempnam(sys_get_temp_dir(), 'srcsign');
                $signed = tempnam(sys_get_temp_dir(), 'mailsign');
                file_put_contents($file, $body);

                //Workaround for PHP bug https://bugs.php.net/bug.php?id=69197
                if (empty($this->sign_extracerts_file)) {
                    $sign = @openssl_pkcs7_sign(
                        $file,
                        $signed,
                        'file://' . realpath($this->sign_cert_file),
                        ['file://' . realpath($this->sign_key_file), $this->sign_key_pass],
                        []
                    );
                } else {
                    $sign = @openssl_pkcs7_sign(
                        $file,
                        $signed,
                        'file://' . realpath($this->sign_cert_file),
                        ['file://' . realpath($this->sign_key_file), $this->sign_key_pass],
                        [],
                        PKCS7_DETACHED,
                        $this->sign_extracerts_file
                    );
                }

                @unlink($file);
                if ($sign) {
                    $body = file_get_contents($signed);
                    @unlink($signed);
                    //The message returned by openssl contains both headers and body, so need to split them up
                    $parts = explode("\n\n", $body, 2);
                    $this->MIMEHeader .= $parts[0] . static::$LE . static::$LE;
                    $body = $parts[1];
                } else {
                    @unlink($signed);
                    throw new Exception($this->lang('signing') . openssl_error_string());
                }
            } catch (Exception $exc) {
                $body = '';
                if ($this->exceptions) {
                    throw $exc;
                }
            }
        }

        return $body;
    }

    /**
     * Prepare a message for sending.
     *
     * @throws Exception
     *
     * @return bool
     */
    public function preSend()
    {
        if (
            'smtp' === $this->Mailer
            || ('mail' === $this->Mailer && (\PHP_VERSION_ID >= 80000 || stripos(PHP_OS, 'WIN') === 0))
        ) {
            //SMTP mandates RFC-compliant line endings
            //and it's also used with mail() on Windows
            static::setLE(self::CRLF);
        } else {
            //Maintain backward compatibility with legacy Linux command line mailers
            static::setLE(PHP_EOL);
        }
        //Check for buggy PHP versions that add a header with an incorrect line break
        if (
            'mail' === $this->Mailer
            && ((\PHP_VERSION_ID >= 70000 && \PHP_VERSION_ID < 70017)
                || (\PHP_VERSION_ID >= 70100 && \PHP_VERSION_ID < 70103))
            && ini_get('mail.add_x_header') === '1'
            && stripos(PHP_OS, 'WIN') === 0
        ) {
            trigger_error($this->lang('buggy_php'), E_USER_WARNING);
        }

        try {
            $this->error_count = 0; //Reset errors
            $this->mailHeader = '';

            //Dequeue recipient and Reply-To addresses with IDN
            foreach (array_merge($this->RecipientsQueue, $this->ReplyToQueue) as $params) {
                $params[1] = $this->punyencodeAddress($params[1]);
                call_user_func_array([$this, 'addAnAddress'], $params);
            }
            if (count($this->to) + count($this->cc) + count($this->bcc) < 1) {
                throw new Exception($this->lang('provide_address'), self::STOP_CRITICAL);
            }

            //Validate From, Sender, and ConfirmReadingTo addresses
            foreach (['From', 'Sender', 'ConfirmReadingTo'] as $address_kind) {
                $this->$address_kind = trim($this->$address_kind);
                if (empty($this->$address_kind)) {
                    continue;
                }
                $this->$address_kind = $this->punyencodeAddress($this->$address_kind);
                if (!static::validateAddress($this->$address_kind)) {
                    $error_message = sprintf(
                        '%s (%s): %s',
                        $this->lang('invalid_address'),
                        $address_kind,
                        $this->$address_kind
                    );
                    $this->setError($error_message);
                    $this->edebug($error_message);
                    if ($this->exceptions) {
                        throw new Exception($error_message);
                    }

                    return false;
                }
            }

            //Set whether the message is multipart/alternative
            /*if ($this->alternativeExists()) {*/
                $this->ContentType = static::CONTENT_TYPE_MULTIPART_ALTERNATIVE;
            /*}*/

            // $this->setMessageType();
            $this->message_type = 'alt';

            //Refuse to send an empty message unless we are specifically allowing it
            if (!$this->AllowEmpty && empty($this->Body)) {
                throw new Exception($this->lang('empty_message'), self::STOP_CRITICAL);
            }

            //Trim subject consistently
            $this->Subject = trim($this->Subject);
            //Create body before headers in case body makes changes to headers (e.g. altering transfer encoding)
            $this->MIMEHeader = '';
            $this->MIMEBody = $this->createBody();
            //createBody may have added some headers, so retain them
            $tempheaders = $this->MIMEHeader;
            $this->MIMEHeader = $this->createHeader();
            $this->MIMEHeader .= $tempheaders;

            //To capture the complete message when using mail(), create
            //an extra header list which createHeader() doesn't fold in
            if ('mail' === $this->Mailer) {
                if (count($this->to) > 0) {
                    $this->mailHeader .= $this->addrAppend('To', $this->to);
                } else {
                    $this->mailHeader .= $this->headerLine('To', 'undisclosed-recipients:;');
                }
                $this->mailHeader .= $this->headerLine(
                    'Subject',
                    $this->encodeHeader($this->secureHeader($this->Subject))
                );
            }
            
            //Sign with DKIM if enabled
            if (
                !empty($this->DKIM_domain)
                && !empty($this->DKIM_selector)
                && (!empty($this->DKIM_private_string)
                    || (!empty($this->DKIM_private)
                        && static::isPermittedPath($this->DKIM_private)
                        && file_exists($this->DKIM_private)
                    )
                )
            ) {
                $header_dkim = $this->DKIM_Add(
                    $this->MIMEHeader . $this->mailHeader,
                    $this->encodeHeader($this->secureHeader($this->Subject)),
                    $this->MIMEBody
                );
                $this->MIMEHeader = static::stripTrailingWSP($this->MIMEHeader) . static::$LE .
                    static::normalizeBreaks($header_dkim) . static::$LE;
            }

            return true;
        } catch (Exception $exc) {
            $this->setError($exc->getMessage());
            if ($this->exceptions) {
                throw $exc;
            }

            return false;
        }
    }
}

// Now to sending an AMP mail is easy, you can use this custom class instead of PHPMailer class
try {
    $mail = new AMPmailPHPMailer(true);
    $mail->isHTML(true);     
    $mail->CharSet = 'UTF-8';
    // $mail->Encoding = 'base64';
    
    // Add the recipient of mail
    $mail->addAddress('john@example.com', 'Deepesh'); 
    
    $mail->Subject = 'AMP Mail Testing with PHPMailer 0.3';
    $mail->Body    = get_html_content();  // Add simple HTML body that will be shown if AMP is not enabled on reciever's gmail settings.
    $mail->AltBody = get_text_content(); // If HTML is not allowed then this content will be shown.

    $mail->AMPBody = get_amp_content(); // Here you will add your AMP mail html
    
    $sendMail = $mail->send();
    if($sendMail){ 
        echo "Success";
    }else{
        echo "Error";
    }

} catch (Exception $e) {
    //Note that this is catching the PHPMailer Exception class, not the global \Exception type!
    echo 'Caught a ' . get_class($e) . ': ' . $e->getMessage();
    echo '<hr>';
    echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}";
}


function get_amp_content(){
  ob_start();
  ?>
  <!doctype html><html ⚡4email data-css-strict>
  <head>
      <meta charset="utf-8">
  <script async src="https://cdn.ampproject.org/v0.js"></script>
  <!-- ## Setup -->
  <!-- Import the carousel component in the header. -->
  <script async custom-element="amp-carousel" src="https://cdn.ampproject.org/v0/amp-carousel-0.1.js"></script>
  
  
  <style amp4email-boilerplate>body{visibility:hidden}</style>
</head>
<body>

  <!-- ## Basic Usage -->
  <!-- Use `type="carousel"` to display a list of images as a continuous strip. -->
  <amp-carousel height="300" layout="fixed-height" type="carousel" role="region" aria-label="Basic usage carousel">
    <amp-img src="https://preview.amp.dev/static/samples/img/image1.jpg" width="400" height="300" alt="a sample image"></amp-img>
    <amp-img src="https://preview.amp.dev/static/samples/img/image2.jpg" width="400" height="300" alt="another sample image"></amp-img>
    <amp-img src="https://preview.amp.dev/static/samples/img/image3.jpg" width="400" height="300" alt="and another sample image"></amp-img>
  </amp-carousel>
  Welcome in AMP email
</body>
        </html>
  <?php
  return ob_get_clean();
}

function get_html_content()
{
	// HTML BODY
}

function get_text_content()
{
	// Text content or notice
}