MySQL, PHP - retrieve data from mysql and email it temperamental - php

Question

I have the following cod which basically sends a message with some user data from MySQL. Now the thing is the email in question gets sent sometimes but not if I need to resend it. Here is the code:
<?php
//including the database connection file
include("config.php");
//getting id of the data from url
$id = $_GET['id'];
//fetching data in descending order (lastest entry first)
$result = mysql_query("SELECT * FROM my_table_name Where id='$id'");
if($res = mysql_fetch_array($result)) {
$name = $res['name'];
$email = $res['email'];
$date = $res['date'];
if(empty($id)) {
echo "<font color='red'>Error: Did not send.</font><br/>";
} else {
// The message
$message = "Hi $name,\r\n\r\nThis email is to inform you that your
\r\n\r\nRegards, \r\n Me.";
$headers = 'From: no-reply#mydomain.org' . "\r\n" .
'Reply-To: no-reply#mydomain.org' . "\r\n" .
'X-Mailer: PHP/' . phpversion();
$Subject = 'Hello';
// Send
mail($email, $Subject, $message, $headers);
//display success message
echo "<font color='green'>Email sent successfully to $name.</font><br/>";
echo "<br/><a href='index.php' class='button button1 link'>Go Back to Overview</a>";
}
}
?>
Any help is greatly appreciated.

Answer 1

If I understood your question correctly and it was about mail function call failing sometimes:
You can add retry logic to your mail call:
$triesLeft = 5;
while ($triesLeft > 0) {
$rc = mail(...);
if ($rc === true) {
break;
}
sleep(1); // Space to improve here - see exponential backoff, for instance
$triesLeft -= 1;
}
if ($triesLeft === 0) {
// Log critical error
}
But this might and will introduce delays in your response time, and in some cases client will even get a timeout.
So usually the solution to this problem is not to send the email right away, but to quickly put it in any kind of queue (even simple db table will suffice), and then make another worker script that will send all that is unsent.
You can move this retry logic to this worker script and sleep all you want, it won't block client.
The only "downsides" to this solution is that:
You will not be able to show result of mail call to your client (which is useless anyway since it means only that is was "accepted for delivery", not actually delivered), and
You'll have a bit more moving parts and you'll have to write a bit more code. But it's either that or accepting that some of your mail calls will fail.
An outline of a solution might be:
form.php (gets called when customer submits form):
get request parameters
form email subject, body from request parameters
save email to db with status = unsent
worker.php (should be always running in an infinite loop or something like that in background on server):
get unsent email from db
try to send it, retrying if needed
if sent successfully - mark email as sent
if failed to send - mark email an failed, log critical error, mitigate manually