Website working error when online but work fine in local XAMPP Server + Mikrotik router

Question

I am building a website that receive POST variables from a Mikrotik router Hotspot page. I used for offline test XAMPP v3.2.2 with PHP 7.1. Everything work fine offline but when i put the website on an online Webserver provided by Cpanel with PHP 7.1 (ea-php71) i got an error with header instruction for redirection.

I got this error :

PHP Warning: Cannot modify header information - headers already sent by

The source code of the page who gave me error

    <?php
    session_start();
    require_once dirname(__FILE__).'/includes/wf_DbOperations.php';
    if(!isset($_SESSION['logincust']))
    {
        header('Location: index.php');
    }
?>
<!DOCTYPE html>
<!--[if IE 9]> <html lang="en" class="ie9"> <![endif]-->
<!--[if !IE]><!-->
<html lang="en">
<!--<![endif]-->
    <head>
        <title>...</title>
    </head>
    <body>
        <?php
            if(isset($_SESSION['oauth_providerG']))
            {
                $db = new DbOperations();
                if(!$db->checkOAUTH($_SESSION['oauth_providerG'],$_SESSION['oauth_uid']))
                {
                    if($db->addUserMAC($_SESSION['oauth_uid'],$_SESSION['mac']))
                    {
                        $db->addUserGoogle($_SESSION['oauth_providerG'],$_SESSION['oauth_uid'],$_SESSION['first_name'],$_SESSION['last_name'],$_SESSION['email'],$_SESSION['gender'],$_SESSION['locale'],$_SESSION['picture'],$_SESSION['link']);
                        header('Location: '.$_SESSION['srvLink'].'/glogin.html');
                    }
                }
                else
                {
                    if($db->addUserMAC($_SESSION['oauth_uid'],$_SESSION['mac']))
                        {
                            header('Location: '.$_SESSION['srvLink'].'/glogin.html');
                        }
                }
            }
            if(isset($_SESSION['oauth_providerF']))
            {
                $db = new DbOperations();
                if(!$db->checkOAUTH($_SESSION['oauth_providerF'],$_SESSION['oauth_uid']))
                {
                    if(isset($_SESSION['email']))
                    {
                        if($db->addUserMAC($_SESSION['oauth_uid'],$_SESSION['mac']))
                        {
                            $db->addUserFacebook($_SESSION['oauth_providerF'],$_SESSION['oauth_uid'],$_SESSION['first_name'],$_SESSION['last_name'],$_SESSION['email']);
                            header('Location: '.$_SESSION['srvLink'].'/glogin.html');
                        }
                    }
                    else
                    {
                        if($db->addUserMAC($_SESSION['oauth_uid'],$_SESSION['mac']))
                        {
                            $db->addUserFacebookNoMail($_SESSION['oauth_providerF'],$_SESSION['oauth_uid'],$_SESSION['first_name'],$_SESSION['last_name']);
                            header('Location: '.$_SESSION['srvLink'].'/glogin.html');
                        }
                    }
                }
                else{
                        if($db->addUserMAC($_SESSION['oauth_uid'],$_SESSION['mac']))
                        {
                          header('Location: '.$_SESSION['srvLink'].'/glogin.html');
                        }
                }
            }
        ?>

    </body>
</html>

I have try redirection with JS script location.replace but it doesn't keep variable send by Mikrotik router.

Thanks for your help.

score 0 · Answer 1 · answered Jan 20 '19 at 16:04

0

You have a space before the first PHP tag.

The web server will send those spaces before getting to the header stuff.

answered Jan 20 '19 at 16:04

Matthew Page

746
5
15

Its ignored by PHP :) So that's not the problem. – Sebastian Waldbauer Jan 20 '19 at 16:05
@SebastianWaldbauer That's not what PHP says about it - http://php.net/manual/en/function.header.php – Matthew Page Jan 20 '19 at 16:11
In his example there's no space before first PHP tag. " – Sebastian Waldbauer Jan 20 '19 at 16:13
@SebastianWaldbauer - in the example above I SEE spaces, – Matthew Page Jan 20 '19 at 16:16
Actually you can serve HTML Code with .PHP file extension. The PHP Interpreter is searching for PHP Tags in .PHP files and start to process this area. Thats why you need open and closing tags in PHP. So the spaces infront of – Sebastian Waldbauer Jan 20 '19 at 16:18
@SebastianWaldbauer But the spaces aren't ignored by Apache, there's more going on than just PHP. Anyway, I hope he takes out those space because it will work. – Matthew Page Jan 20 '19 at 16:21
I don't have space before the first PHP tag, it was before the second after the "" declaration. I remove it but nothing change. No error now but white empty page – T.Rudy Jan 20 '19 at 16:47

score 0 · Accepted Answer · answered Jan 20 '19 at 16:10

0

In your PHP script you use header(). Somewhere you try to manipulate data from header(), but this data was already sent as you can read in this Error message

PHP Warning: Cannot modify header information - headers already sent by

So after all your header() make sure you tell the script to exit correctly. source

answered Jan 20 '19 at 16:10

Sebastian Waldbauer

674
1
10
17

I have added exit; instruction after all header(), now no error but the script show a white page. Some debugging tips?? – T.Rudy Jan 20 '19 at 16:42
Your script doenst show any kind of data, its only redirecting. You can use ```echo $_SESSION['logincust']``` to check if data is present. – Sebastian Waldbauer Jan 20 '19 at 16:45

score 0 · Answer 3 · answered Jan 20 '19 at 16:16

0

if(!isset($_SESSION['logincust']))
{
    header('Location: index.php');
    exit(0);
}

If you have any code (Html or Php) under header you should use exit.

answered Jan 20 '19 at 16:16

Eren

101
2
6

Website working error when online but work fine in local XAMPP Server + Mikrotik router

3 Answers3