cannot modify header information - Download File

Question

I am struggling to wrap my head around this.

I am creating two forms on a page to generate a configuration file for a device, one form for each of the two different devices we use. The form works fine and submits the values correctly, but I need the file to initiate a download. Using one form I have been able to achieve this, but with two forms I get an error regarding the header information.

Here is the head of my file

<html>
<head>
  <link rel="stylesheet" type="text/css" href="screen.css" />
  <?php 
      include('header.php'); 
      include('config/wan.php');
      include('config/wan-voip.php');
      include('config/pppoe.php');
      include('config/pppoe-voip.php');
      include('config/dlink.php');
   ?>
 </head>
<body>

This si followed by the a standard HTML form and then here is my code to validate the inputs and act accordingly:

if(isset($_POST['submit']))
{

    if(!empty($_POST['type']) && isset($_POST['router']) && $_POST['router'] == 'netgear')
    {
        if($_POST['type'] == 'pppoe' && (empty($_POST['username']) || empty($_POST['password'])))
        {
            echo 'Please fill in the username and password';
            exit;
        }



        if(empty($_POST['ssid']) || empty($_POST['pass']))
        {
            echo 'Please provide the SSID and Wireless Key';
            exit;
        }

        if(($_POST['type'] == 'wan-voip' || $_POST['type'] == 'pppoe-voip') && (empty($_POST['ext']) || empty($_POST['extpass'])))
        {
            echo 'Please provide the Extension Information';
            exit;
        }
    }
    elseif(isset($_POST['router']) && $_POST['router'] == 'dlink')
    {
        if(empty($_POST['ssid']) || empty($_POST['pass']))
        {
            echo 'Please provide the SSID and Wireless Key';
            exit;
        }
    }


    ob_end_clean();

    if($_POST['router'] == 'netgear')
    {
        header("Content-type: text/plain");
        header("Content-Disposition: attachment; filename=".date('d-m-Y')."-".$_POST['type'].".ini");

        $file = str_replace('-', '', $_POST['type']); 
        echo $$file;
    }
    elseif($_POST['router'] == 'dlink')
    {
        header("Content-type: text/plain");
        header("Content-Disposition: attachment; filename=".date('d-m-Y')."-dlink.cfg");
        echo $dlink;
    }



}

Could someone please suggest how I could go about solving this. I have read some other related spots and tried moving bits of the script around and trying some of the suggestions but I seem to keep hitting brick walls.

score 2 · Accepted Answer · answered Oct 27 '14 at 10:17

in http protocol, headers should always be sent before body.

that is why you are getting this error, you are using

header("Content-type: text/plain");

after you have already outputted some text.

if you want to use the header method, you have to do it before any 'echo' or any text output

cannot modify header information - Download File

1 Answers1