php mail() two copies sent

Question

I have a simple message that I send using php mail(). The code used:

//recipient info
$to = \"$bookernavn <$mail>\";
$from = \"Visens Venner Hillerød &         


        

Answer 1

You don't check to see if the form has been submitted so a browser refresh will send the form data again and cause the mail to be sent again. This also happens when a user presses the back button.

After the email is sent you need to do a 303 redirect to prevent the re-submission. You can redirect to the same page if you'd like.

This is called the Post/Redirect/Get pattern.

mail(...);
header('Location: /some-page-php', true, 303);
exit;

Answer 2

an easy way to prevent this from happening is to use POST method instead of GET for the form.

<form method="post">



if (isset($_POST['submitted']))

and at the end of the mail code use a redirect that will send the browser to load using a GET method.

Not only you can then redirect your user to a OK page "mail was sent" or a error page "sorry there was a mistake, please try again", a refresh of that page open by the browser will only send a GET, not triggering the send mail function

if (empty($errors)) {
  header('Location: http://www.example.com/mail_OK.html');
  exit;
} else {
  // passing data to the "error/retry" page
  $info = array(
    'msg' => $msg,
    'email' => $_POST['email'],
    'name' => $_POST['name']
    // etc...
  )
  header('Location: http://www.example.com/mailform.php?'.http_build_query($info));
  exit;
}

in your form you can retrieve those info

<input name="name" type="text" placeholder="Naam" class="form-control" value="<?php echo htmlspecialchars($_GET['name']); ?>">