PHPMailer function to send without SMTP if SMTP fails - php

Question

I've written the following code to send email using PHPMailer. But what i'm trying to get working is first attempt a send via SMTP TLS and if that fails then send the mail without SMTP. But the code seems to fail because it doesn't like to run the PHPMailer function twice. If I run the function once either calling it to send via SMTP or not both work. But it doesn't work if SMTP fails.
function processEmail($to, $message, $skip_smtp){
date_default_timezone_set('Europe/London');
require 'PHPMailer/PHPMailerAutoload.php';
$mail = new PHPMailer;
if (!isset($skip_smtp) || empty($skip_smtp)){
$mail->isSMTP();
}
$mail->SMTPDebug = 0;
$mail->Debugoutput = 'html';
$mail->Host = 'smtp.domain.com';
$mail->Port = 587;
$mail->SMTPSecure = 'tls';
$mail->SMTPAuth = true;
$mail->Username = "my_smtp_username";
$mail->Password = "my_smtp_password";
$mail->setFrom('from#myemail.com', 'From Name');
$mail->addAddress($to, $to);
$mail->msgHTML($message);
if (!$mail->send()) {
return false;
} else {
return 1;
}
}
$smtp_result = processEmail($to, $message);
if ($smtp_result>=1){
echo "Sent using secure TLS SMTP";
} else {
processEmail($to, $message, 1);
echo "SMTP Failed - Attempted to send without SMTP ";
}

Answer 1

Looking at your existing code, I've gathered that your relaying mail over another SMTP server so unsure why your testing if TLS is available. Does your relaying server sometimes fail on TLS? The below solution would be best suited using OOP as this function is a bit excessive. I've heavily commented so my logic should be pretty straight forward. Some of the key points is that the function is Recursive meaning it will call it self if TLS fails keeping the code running inside one function. Secondly, re-using PHP Mailer with the same execution will have issues so I have unset() the initial $mail object on second call as well as setting the include to require_once. As noted, you will need to check with your SMTP provider on the TLS port used and SMTP port (if any) to ensure it works. I've tested with my provider and this works with no issues.
function sendEmail($to, $message, $skip_smtp=1) {
date_default_timezone_set('Europe/London');
require_once 'PHPMailer/PHPMailerAutoload.php';
//You will need to check your provider for these settings
if ($skip_smtp === 0) {
$port = 25; //Usual port for non TLS/SSL
} else {
$port = 465; //Port for relay server - likely to be 25, 465 or 587
$mail->SMTPSecure = 'tls'; //Send via TLS Encryption - SSL or TLS (Dependent on Relay Server)
}
$mail = new PHPMailer();
$mail->SMTPDebug = 3; //Enabled this so you can see what's happening - Dont forget to set to 0 in production
$mail->Debugoutput = 'html';
//SMTP Relay Server Settings
$mail->isSMTP(); //Send as SMTP - Should always be set unless you would like to use another method like sendmail()
$mail->Host = 'smtp.relay.com';
$mail->Port = $port;
$mail->Timeout = 5; //Set your Timeout in Seconds - Default is 5mins which is abit excessive when testing
$mail->SMTPAuth = true; //Relay Server Auth Details
$mail->Username = "SMTP RELAY USERNAME";
$mail->Password = "SMTP RELAY PASSWORD";
//Email Details
$mail->setFrom('test#test.com');
$mail->addAddress($to);
$mail->Subject = 'My Subject';
//Email Content
$mail->isHTML(true); //Set HTML
$mail->Body = $message; //HTML Body
$mail->AltBody = $message; //Failover for Non-HTML
switch ($mail->send()) {
case false:
if ($skip_smtp === 0) {
echo 'Message could not be sent.';
echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
echo 'Error Sending TLS...trying Non TLS';
unset($mail); //Unset Object
sendEmail($to, $message, $skip_smtp=0); //Recursive function -> passing 0 to skip TLS
}
break;
case true :
echo 'Message has been sent';
break;
default :
echo 'Error';
}
}
//Your Function
sendEmail('test#test.com', 'Test Body');
?>