Cannot modify header information headers already sent by output

Question

Delete image than redirect the page with query string i add query string with header but its not working Header not working

Error

headers already sent by output started at sidebar.php in delete.php

Delete.php

if(!isset($_SESSION['admin_email'])){

echo "<script>window.open('login.php','_self')</script>";

}

else {

if(isset($_GET['delete'])){
$id = $_GET['delete'];
$page = $_GET['page'];
$image = $_GET['image'];
$section = $_GET['section'];
$delete_p_cat = "delete from $page where id='$id' AND section = '$section'";
$run_delete = mysqli_query($con,$delete_p_cat);

if($run_delete)
{
  header('Location: index.php?view&page='.$page.'&section='.$section);
  exit();
}
 }
} ?>

index page check if page exist than load the page sidebar included in index page index.php

   <div id="wrapper">

   <?php include("includes/sidebar.php");  ?>

  <div id="page-wrapper">

   <div class="container-fluid">

   <?php

   if(isset($_GET['dashboard'])){

    include("dashboard.php");

   }
    if(isset($_GET['view'])){

    include("view.php");

   }
   if(isset($_GET['delete'])){

    include("delete.php");

   }

   </div>

   </div>

  </div>

Possible duplicate of [How to fix "Headers already sent" error in PHP](https://stackoverflow.com/questions/8028957/how-to-fix-headers-already-sent-error-in-php) — Shira, Apr 09 '18 at 12:59
Well it's *definitely* a duplicate then; you're including `delete.php` inside a file that's spaffing out HTML. — CD001, Apr 09 '18 at 13:06

parmar84 · Accepted Answer · 2018-04-09T13:34:26.897

You are getting this error because you are already outputting content before setting a header.

If your include("delete.php"); is going to redirect then you will need to perform this before outputting content.

try...

// before any output
if(!isset($_SESSION['admin_email']) && isset($_GET['delete'])){
    include("delete.php");
}
?>
<div id="wrapper">
<?php include("includes/sidebar.php");  ?>

<div id="page-wrapper">

<div class="container-fluid">

<?php

  if(isset($_GET['dashboard'])){
    include("dashboard.php");
  }
  if(isset($_GET['view'])){
    include("view.php");
  }
  if(isset($_GET['delete'])){
    // remove this from delete.php
    if(!isset($_SESSION['admin_email'])){
      // looking at it, this may also want to be at the top 
      // if you are checking for a 'logged in user'
      echo "<script>window.open('login.php','_self')</script>";
    }
  }
</div>

</div>

Cannot modify header information headers already sent by output

1 Answers1