A few years ago I wrote a small PHP function to send mails via SMTP. Not so long ago a friend asked for it. So I cleaned it up and wrote a bit of documentation: smtp_send. It won’t work for everyone but it’s only about 90 lines of code and you can easily change it to suite your needs.
If you don’t care about dependencies or code footprint you can use one of the many libraries out there. But if you’re tired of PHPs mail() function, overly complicated APIs or huge amounts of dependencies just to send mails this might be worth a look. The function is meant for people who want to construct the mails themselves. Either for simplicity or because of more complex cases. Then you can use the function to simply send the result.
Usage example:
$message = <<<EOD
From: "Mr. Sender" <sender@dep1.example.com>
To: "Mr. Receiver" <receiver@dep2.example.com>
Subject: SMTP Test
Date: Thu, 21 Dec 2017 16:01:07 +0200
Content-Type: text/plain; charset=utf-8
Hello there. Just a small test. 😊
End of message.
EOD;
smtp_send('sender@dep1.example.com', 'receiver@dep2.example.com', $message,
'mail.dep1.example.com', 587,
array('user' => 'sender', 'pass' => 'secret')
);
I put it online because my friend searched for a simple PHP mailer but couldn’t find one matching the projects requirements. I had the same experience a few years ago. In the end decided to look at the SMTP RFC and write my own little function. With a bit of luck this makes your life easier if you’re caught in same corner cases.
The documentation also contains examples of mails with attachments, alternative content (HTML mail with plain text fallback) or both (alternative content nested in mixed content). For some reason this information seems to be surprisingly hard to find.