Thursday, February 5, 2015

PHP Sending mails twice?? (doing stuff twice)

Just had a mammoth troubleshooting session, because a very simple PHP script to send an email kept sending them twice. I’d only just configured postfix to send email, so I kept looking for problems there. I kept staring at the PHP code, and could see no problem, but it looked more and more like PHP was calling postfix twice. Commenting php.ini settings in and out made no difference. This was commandline PHP, so nothing to do with browser reloads, or anything like that.

Then I had the brainwave to append a random number to the bottom of the body text. Different numbers; in fact, not just that, but the 2nd email got both numbers! So it is definitely my PHP script. But I still couldn’t see it.

Stripped down, so the problem is more obvious, it looked like this:

$bodyText = "Whatever";

class Test{

function test(){
mail("", "Test", $bodyText);

$R = new Test;

I’ve been spending too much time jumping between languages. And I’d also got used to PHP constructors being called __construct() and forget it still offered backwards compatibility for using the class name. Yep, that’s right, PHP functions (and classes) are case-insensitive, and so test() was being treated as the constructor of class Test. So one mail was being sent from the constructor, the second from my explicit function call. Grrrr….

(The above is also a possible explanation for problems like “PHP calls web service twice”, or “PHP has double log entries” or “PHP does something twice”!)

Written with StackEdit.

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