John Davidson

Message:

Some question's, and articles I've been reading regarding EML creation

• How to verify DKIM signature from an e-mail with openssl?


• PHP library to generate EML email files?


• https://www.icosaedro.it/phplint/mailer-tutorial/index.html


• https://coderedirect.com/questions/25620/php-library-to-generate-eml-email-files (This one is interesting, but it would need extending for DKIM signatures)


• https://www.example-code.com/phpExt/smtp_loadEmlAndSend.asp (only does SMTP send)


• https://community.apachefriends.org/f/viewtopic.php?t=79968&p=270281 (this works great for Linux, haven't been able to find Windows equivalent)


• Use of mailtodisk / mailoutput in XAMPP for Linux (Great concept)


• https://swiftmailer.symfony.com/docs/introduction.html (This is from Symfony yet to see if works without Symfony but no longer maintained)

I can't seem to find any standalone class files that will generate the contents for *.eml that can be either stored into file (using file_put_contents) or temporarily into a variable.

The idea is that I can create my *.eml file server-side I could use the contents to verify a DKIM signature, without having to actually send an email.

I did find one library phplint that does what I want, but it is far too big for what I need (635 Files, 53 Folders 7.84 MB (8,224,768 bytes)).

$m = new Mailer();

$m->setSubject("This is the subject");

$m->setFrom("[email protected]", "My Name");

$m->addAddress("[email protected]", "Your Name");

$m->setTextMessage("This is the text body of the message.");

$m->sendByStream($out_string, TRUE);

$message_as_string = $out_string->__toString();

The above snippet uses the following classes to generate the message.

[180] => it\icosaedro\email\Mailer

[181] => it\icosaedro\io\IOException

[182] => it\icosaedro\utils\StringBuffer

[183] => it\icosaedro\io\OutputStream

[184] => it\icosaedro\io\StringOutputStream

[185] => it\icosaedro\email\Field

[186] => it\icosaedro\email\MIMEAbstractPart

[187] => it\icosaedro\email\Header

[188] => it\icosaedro\email\MIMEPartMemory

[189] => it\icosaedro\email\EOLFilter

[190] => it\icosaedro\utils\Random

I've been looking all over github, as well as PHPClasses. But I can't anything relevant to what I need (with enough research I could probably build it myself but I'd prefer not to reinvent the wheel).

Ideally I'm looking for possibly an extension of PHPMailer, that can stream the EMAIL either to File or String Variable). I also need the class or function to work on both linux and windows.

If somebody can just find a library or point me into the right direction, I'd much appreciate it.

---

My Answer:
To generate an EML file with a DKIM signature in PHP, you can follow these steps:

1. Use a PHP library like PHPMailer or Swift Mailer to create the email message and headers.
2. Generate the DKIM signature using a library like php-dkim.
3. Add the DKIM signature to the email headers.
4. Save the email as an EML file.

Here is an example code snippet using PHPMailer and php-dkim to generate an EML file with a DKIM signature:

php
require 'vendor/autoload.php'; // Include PHPMailer library
require 'vendor/php-dkim/autoload.php'; // Include php-dkim library

// Create a new PHPMailer instance
$mail = new PHPMailer\PHPMailer\PHPMailer();

// Set the email content and headers
$mail->setFrom('[email protected]', 'Sender Name');
$mail->addAddress('[email protected]', 'Recipient Name');
$mail->Subject = 'Test Email with DKIM Signature';
$mail->Body = 'This is a test email with a DKIM signature';

// Generate the DKIM signature
$dkim = new phpDKIM\DKIM($mail->getSentMIMEMessage(), 'example.com', 'selector', 'private_key.pem');
$dkim_signature = $dkim->getSignature();

// Add the DKIM signature to the email headers
$mail->addCustomHeader('DKIM-Signature', $dkim_signature);

// Save the email as an EML file
file_put_contents('test_email.eml', $mail->getSentMIMEMessage());

echo 'EML file with DKIM signature generated successfully.';


This code snippet assumes that you have already set up your DKIM keys and have the private key stored in a file named `private_key.pem`. Make sure to replace `'example.com'`, `'selector'`, and the email addresses with your own values.

You can further customize the email content, headers, and DKIM settings according to your requirements.