Mpdf giving fault and not outputting pdf

Question

I am using Mpdf which is working fine locally, the trouble I am having is that the pdf wont output and just get a blank screen

Here is the error

Fatal error: Uncaught Mpdf\MpdfException: Data has already been sent to output (/customers/3/c/2/includes/header.php at line 14), unable to output PDF file in /customers/3/c/2/pdf/vendor/mpdf/mpdf/src/Mpdf.php:9510 Stack trace: #0 /customers/3/c/2: Mpdf\Mpdf->Output('sold.pdf', 'I') #1 /customers/3/c/2/include('/customers/3/c/...') #2 {main} thrown in /customers/3/c/2/pdf/vendor/mpdf/mpdf/src/Mpdf.php on line 9510

Couple of things I have tried, encoding is correct at UTF and NOT DOM, I have no white space, and everything seems to be ok

This is the header code

<?php
        session_start();
            if(empty($_SESSION['user_id']))
                {
                header("Location: https://www.home.co.uk");
                }
        require '../dbcon/database.php'; 
        $db = DB();
        require '../lib/library.php'; 
        $app = new WIDGET();
        require '../lib/carbon.php';
        $user = $app->UserDetails($_SESSION['user_id']); 
        ?>

I have also tried

<?php
        session_start();
        require '../dbcon/database.php'; 
        $db = DB();
        require '../lib/library.php'; 
        $app = new WIDGET();
        require '../lib/carbon.php';
        $user = $app->UserDetails($_SESSION['user_id']); 
        ?>

Which has made no difference.

And this is the code in line 9510 of Mdpf.php

case Destination::INLINE:

            if (headers_sent($filename, $line)) {
                throw new \Mpdf\MpdfException(
                    sprintf('Data has already been sent to output (%s at line %s), unable to output PDF file', $filename, $line)
                );
            }

Like mentioned all I am getting is a blank page, if I output to an iframe it works ok. Works fine on 127.0.0.1

Any help much appreciated and thanks in advance for any help

Update:

Sorry forgot to mention or show the code calling the pdf.

I have already tried ob_clean() and still no go

require_once 'pdf/vendor/autoload.php';
    if(ob_get_length() > 0) {
    ob_clean();
    }
    $mpdf = new \Mpdf\Mpdf();   
    $html ='<html>
    <body>
    <h2 style="font-size: 120px; text-align:center;">SOLD</h2>
    <h2 style="font-size: 50px; text-transform: uppercase; text-align:center;">'.   $row->widget_model .'</h2>
    <h2 style="font-size: 50px; text-transform: uppercase; text-align:center;">'. $row->widget_serial .'</h2><br>
    <h2 style="font-size: 30px; text-transform: uppercase; text-align:center;">Delivery Date: '. (new DateTime($_POST['expdelivery']))->format('d-m-Y') .'</h2>
    <br>
    <h2 style="font-size: 20px; text-align:center;">Contact: '. $_POST['name'] .'</h2>
    </body>
     </html>';
     $mpdf->WriteHTML($html);
     $mpdf->Output('sold.pdf','I');
     ob_end_flush();
     }

EDIT 2:-

Looking at the network Tab it is just showing all the js calls and favicon.ico

It also shows this page updatewidget.php?id=2178

<?php
        $page_title = "Widget Tracker - Amend Widget"; 
        $page = ''; 
        include "includes/header.php";
        include "includes/sidebar.php";
            $id = isset($_GET['id']) ? $_GET['id'] : NULL;
            $sth = $db->prepare("SELECT *  FROM `widgettracker` WHERE `id` = :id");
            $sth->bindParam(':id', $id, PDO::PARAM_INT);
            $sth->setFetchMode(PDO::FETCH_OBJ);
            $sth->execute(); 
            $row = $sth->fetch();
            ?>
            <section class="content">
                <div class="container-fluid">
               <?php
                    if($row->widgetstatus == "Sold") 
            {include "sold.php";}
            else
            {include "widgetdetails.php";}
            ?>
            </div>
            </section>
        <?php
        include "includes/footer.php";
        include "includes/customjs.php";
        ?>

And the page that has the Mpdf on is "widgetdetails.php" I need to insert a Sold date and update and generate the pdf. Then the error

The error is suggesting that output or headers have already been sent. This could be some output from your PHP file after the ?> tags but with the little snippets you've provided, it's unclear to see where it is originating from. If all else fails, you could call ob_clean() before attempting to output the Mpdf result. — Reece
Thanks for updating. Could you check the raw data received from the browser? Should be accessible via Inspect Element or right-click the white page and View Source. — Reece

Samuel Samuel · Accepted Answer · 2020-08-04T16:07:45

You might have a blank line or newline after the closing ?> in your header file. Try removing the closing ?> from your php files that are not actually outputting anything.

Mpdf giving fault and not outputting pdf

2 Answers