PHPMailer best solution for looping through emails - php

Question

I am trying to build a recall system in which users are sent reminder emails based on specified criteria. At the moment I would probably be sending 10-15 reminders at a time each week but it's possible that this may escalate to hundreds each week in the future. I've decided to use PHPMailer class to handle mail sending but I am very new to PHPMailer and so i'm not sure if the solution I have come up with will give the best performance or if my code can be improved. Also I am storing the date the email has been sent once it has been sent successfully.
This is what I have come up with:
<?php
//I have left out the database connection details for obvious reasons
require 'PHPMailer-master/PHPMailerAutoload.php';
$result = mysql_query("SELECT * FROM patients_test WHERE recall <> 0 AND DATE_ADD(`last_seen`, INTERVAL recall DAY) < DATE_ADD(NOW(), INTERVAL 21 DAY)");
while($row = mysql_fetch_array($result))
{
//Create new mail object
$mail = new PHPMailer;
///Mail settings
$mail->isSMTP(); // Set mailer to use SMTP
$mail->Host = 'host.co.uk'; // Specify main and backup SMTP servers
$mail->SMTPAuth = true; // Enable SMTP authentication
$mail->Username = 'myusername'; // SMTP username
$mail->Password = 'mypassword'; // SMTP password
$mail->SMTPSecure = 'tls'; // Enable encryption, 'ssl' also accepted
$mail->From = 'myusername';
$mail->FromName = 'Mailer';
$mail->addReplyTo('replytoadd', 'Information');
$mail->WordWrap = 50; // Set word wrap to 50 characters
$mail->addAttachment('/var/tmp/file.tar.gz'); // Add attachments
$mail->isHTML(true); // Set email format to HTML
$mail->Subject = 'Reminder email';
$mail->Body = 'This is the HTML message body <b>in bold!</b>';
$mail->AltBody = 'This is the body in plain text for non-HTML mail clients';
//Recipient info
$ref = $row['identifier'];
$first_name = $row['first_name'];
$surname = $row['surname'];
$email = $row['email'];
$mail->addAddress($email, $first_name." ".$surname); // Add a recipient
if(!$mail->send())
{
echo 'Message could not be sent.';
echo 'Mailer Error: ' . $mail->ErrorInfo;
}
else
{
echo 'Reminder sent to '.$first_name.' '.$surname.' successfully<br/>';
mysql_query("UPDATE patients_test SET last_reminder= CURDATE() WHERE identifier='$ref'");//Update database to show that email has been sent
$mail->clearAllRecipients();
}
}
?>
Also the reason why I chose not to use PHPs default mail() function is because I am worried that my emails will be blocked as spam and I read somewhere that using something like PHPMailer can reduce the chances of this happening. Does anyone have any advice on this issue?
Thanks in advance
Rich

Answer 1

Fill the mail's headers can reduce this issue. The mail server have some rules which define if the mail is a spam or not. Moreover, sending mails through a loop may cause a blocking depending on how it is configured.