Is there a way to use the transactions in TCPDF when extending it with FPDI?

Question

I am using TCPDF with FPDI's bridge. The issue I'm having is that as soon as I use the startTransaction() I get the following error:

TCPDF ERROR: Cannot access protected property FPDI:$numpages / Undefined property: FPDI::$numpages

and the script ends (because of the die in the TCPDF::Error() method).

Here is the code I'm using:

$pdf = new FPDI();

// add a page
$pdf->AddPage();

$pdf->startTransaction();
$pdf->Cell(0, 0, 'blah blah blah');
$pdf->rollbackTransaction();

$pdf->Output( . time() . '.pdf', 'D');

If I change it to:

$pdf = new FPDI();

// add a page
$pdf->AddPage();

$pdf->Cell(0, 0, 'blah blah blah');

$pdf->Output( . time() . '.pdf', 'D');

it works fine.

Is there anyway to make them work together and use TCPDF's transactions?

Answer 1

The solution I found was to to use PHP's object cloning which allows me to do transactions and roll them back whenever I want. Here's an example:

$pdf = new FPDI();

// add a page
$pdf->AddPage();

$pdf->Cell(0, 0, 'blah blah blah');

$_pdf = clone $pdf;

// do stuff that you may want to revert
$pdf->Cell(0, 0, 'PDFs suck!');

// revert the PDF
$pdf = $_pdf;

$pdf->Output( . time() . '.pdf', 'D');

The PDF will only contain "blah blah blah".

Answer 2

in your first example you should use $pdf = $pdf->rollbackTransaction or $pdf->rollbackTransaction(true) instead of just $pdf->rollabackTransaction()

this is because rollbackTransaction takes a boolean parameter (default is false), to know if it have to return the rollbackvalue (false) or set the object to the rollback state (true).

Answer 3

$pdf = new FPDI(); 

$pdf->AddPage();

$pdf->startTransaction(true);

$pdf->Cell(0, 0, 'blah blah blah');

$pdf->rollbackTransaction(true);

$pdf->Output( . time() . '.pdf', 'D');

Adding true as parameter in the Transaction Method Calls solved the Problem for me.