Call to a member function set_signature_certificate() on bool - php

Question

could you help me with this problem?
I am trying to create and download a signed PDF.
Once the generated PDF file exists, I can't sign in because of this error.
"Call to a member function set_signature_certificate() on bool"
in browser and
"Error info at /Users/martinkravec/git/projectname/vendor/ddn/sapp/src/PDFUtilFnc.php:377: PDF version string not found"
in stderr.log.
I am running the following code outside CLI in Laravel 9 with PHP 8.1.9.
config/app.php
in provider:
Barryvdh\DomPDF\ServiceProvider::class,
In aliases:
'PDF' => Barryvdh\DomPDF\Facade::class,
Controller
use PDF;
use ddn\sapp\PDFDoc;
if (!defined('STDERR')) define('STDERR', fopen(__DIR__ . '/../../../storage/logs/stderr.log', 'wb'));
require_once(__DIR__ . '/../../../vendor/autoload.php');
class ClientController extends Controller
{
public function index()
{
$pdf = PDF::loadView('pdf'); // temlate in resources/views/pdf.blade.php
$fileContent = $pdf->stream();
$obj = PDFDoc::from_string($fileContent);
$certificatePath = __DIR__ . '/../../../storage/app/test_certificate.pfx';
$password = '';
$obj->set_signature_certificate($certificatePath, $password);
$signedPdf = $obj->to_pdf_file_s();
return response()->streamDownload(function () use ($signedPdf) {
echo $signedPdf;
}, 'export.pdf');
}
}
When I do
cat ./file.pdf
I get file content starting with:
HTTP/1.0 200 OK
Cache-Control: no-cache, private
Content-Disposition: inline; filename="document.pdf"
Content-Type: application/pdf
Date: Sun, 28 Aug 2022 09:37:03 GMT
%PDF-1.7
1 0 obj
<< /Type /Catalog
/Outlines 2 0 R
/Pages 3 0 R >>
endobj
2 0 obj
<< /Type /Outlines /Count 0 >>
endobj
3 0 obj
<< /Type /Pages
/Kids [6 0 R
19 0 R
]
/Count 2
/Resources <<
/ProcSet 4 0 R
/Font <<
/F1 8 0 R
/F2 13 0 R
>>
/XObject <<
/I1 18 0 R
>>
>>
/MediaBox [0.000 0.000 595.280 841.890]
>>
endobj
4 0 obj
[/PDF /Text /ImageC ]
endobj
5 0 obj
<<
/Producer (���d�o�m�p�d�f� �2�.�0�.�0� �+� �C�P�D�F)
/CreationDate (D:20220828113702+02'00')
/ModDate (D:20220828113702+02'00')
/Title (���D���v�k�y�.�P�D�F)
>>
endobj
6 0 obj
<< /Type /Page
/MediaBox [0.000 0.000 595.280 841.890]
/Parent 3 0 R
/Contents 7 0 R
>>
endobj
7 0 obj
<< /Filter /FlateDecode
/Length 919 >>
stream

Answer 1

I have found the problem.
Instead of reading the PDF file content using
$pdf->stream()
we need to save the file using
$pdf->save($fileName);
which does not generate the first 6 lines of a file and probably some more things causing an error with the version.
Thanks for helping #Peppermintology anyway.