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Sessions, Headers & PDF

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Join Date: Aug 2009

Posts: 3

Reputation: ANicholson is an unknown quantity at this point

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ANicholson ANicholson is offline

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Sessions, Headers & PDF

Aug 25th, 2009

Hi,

I'd be grateful for a little help. I have a script which generates invoices as PDF files and stores above just above www level (so they cannot be access directly via a URL).

I would like users to be able to access their own invoices but nobody elses.

My script as it stands is as follows:

 Help with Code Tags 
 PHP Syntax (Toggle Plain Text) 
<?php
 
session_start();
 
if($_SESSION['auth']==false){
   header("HTTP/1.0 404 Not Found");
   exit();
}
 
$invoice_id = $_GET['vid'];
$user_id = $_SESSION['userid'];
 
if (is_numeric ($invoice_id)) 
{
   require(db.php);
 
   $q = $dbh->query(...);
   $n = $q->fetchColumn();
 
   if($n==1){
 
     //output pdf
 
     $filename = "../invoices" . $invoice_id . ".pdf";
 
     header('Content-type: application/pdf');
	header('Content-Disposition: attachment; filename="invoice.pdf"');
	readfile($filename);
 
   }
 
}
<?php

session_start();

if($_SESSION['auth']==false){
   header("HTTP/1.0 404 Not Found");
   exit();
}

$invoice_id = $_GET['vid'];
$user_id = $_SESSION['userid'];

if (is_numeric ($invoice_id)) 
{
   require(db.php);

   $q = $dbh->query(...);
   $n = $q->fetchColumn();

   if($n==1){

     //output pdf
     
     $filename = "../invoices" . $invoice_id . ".pdf";

     header('Content-type: application/pdf');
	header('Content-Disposition: attachment; filename="invoice.pdf"');
	readfile($filename);

   }

}

I've posted a slimmed down the code here and changed a few variable names for security reasons but essentially its the same as what I'm working with.

The basic codes works. The problem arises when an authorised user calls the file. The PDF file is returned, it is not rendered correctly e.g. you see "%PDF-1.7 3 0 ...". I presume this is because session_start() acts like a header? Is there any way round this.

Last edited by ANicholson; Aug 25th, 2009 at 9:48 am.

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Join Date: Nov 2007

Posts: 3,761

Reputation: nav33n is a jewel in the rough

Solved Threads: 332

nav33n

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Re: Sessions, Headers & PDF

Aug 25th, 2009

Try

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
 <?php ob_start(); ?>
 <?php ob_start(); ?>

to turn on output buffering (should be the 1st line of your code) and

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
<?php ob_flush(); ?>
<?php ob_flush(); ?>

as the last line to flush the buffered output.

Ignorance is definitely not bliss!

*PM asking for help will be ignored*

•

Join Date: Aug 2009

Posts: 3

Reputation: ANicholson is an unknown quantity at this point

Solved Threads: 0

ANicholson ANicholson is offline

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Newbie Poster

Re: Sessions, Headers & PDF

Aug 25th, 2009

Just to clarify, like so?

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
<?php
ob_start();
 
// .. all my other code
 
ob_flush();
 
?>
<?php
ob_start();

// .. all my other code

ob_flush();

?>

If so, no joy

•

Join Date: Nov 2007

Posts: 3,761

Reputation: nav33n is a jewel in the rough

Solved Threads: 332

nav33n

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Senior Poster

Re: Sessions, Headers & PDF

Aug 25th, 2009

Hmm.. I tried your code snippet and it worked fine. There is one thing that I'd always do after having a header, an exit. This might or might not fix the problem, but try having an exit after readfile function.