I want to echo something in a post after submitting a form, then redirecting the header to cancel the double submit problem. Currently, Output_buffering turned on to allow the redirect to work. here some example code that illustrates the problem. Just make sure Output_buffering is on in php.ini.
<?php
if(isset($_POST['submit'])){
echo "hi";
}
if (count($_POST) {
header("Location: ".$_SERVER['REQUEST_URI']);
exit();
}
?>
<form action="<?php echo htmlentities($_SERVER['REQUEST_URI']); ?>" method="POST" name="edit" >
<button type="submit" value="submit" name="submit">edit</button>
</form>
You should reverse the order.
On submit:
On message page show:
It's can be separate page, same page, as with submit for, or any other page.
Or... Do the work with JavaScript and AJAX:
<?php
if(isset($_POST['submit'])) {
...
if (/all is ok/)
die(json_encode(array('status' => 'ok', 'message' => 'Hi!')));
else {
die(json_encode(array('status' => 'err', 'message' => 'I\'m failed!')));
}
}
?>
<form action="<?php echo htmlentities($_SERVER['REQUEST_URI']); ?>" method="POST" name="edit" >
<button type="submit" value="submit" name="submit">edit</button>
</form>
<script language="javascript">
$('form').submit(function() {
var parameters = ...; // collect parameters from form
$.getJSON('/url-to-script', parameters)
.success(function(response) {
if (response.message == "ok")
alert(response.message);
else
alert('Can\'t process input:
' + response.message);
})
.error(function(response) {
alert('What a terrible failure!');
});
});
</script>
When .success() fired - you can show supplied message to user via alert/custom modal message box an then make redirect (document.location = '<?php echo ... ?>') or replace form on page with some custom message and link/button to proceed... Lots of variants.
Headers must be sent BEFORE any content (that's what echo gives).
You could store your message into session and print it on next request (which would be your follow up redirect).
EXAMPLE:
sessions_init.php
<?php
session_start();
post.php
<?php
include_once 'sessions_init.php';
// assuming POST succeeded, data is valid, etc
$_SESSION['messages'][] = 'You have been redirected';
header("Location: ".$_SERVER['REQUEST_URI']);
exit();
html template:
include_once 'sessions_init.php';
// print HTML:
// <html><head>...</head><body>...
foreach($_SESSION['messages'] as $message) {
print($message);
}
// some other content </body></html>