barryvdh/laravel-dompdf renders blank web page - laravel

Question

I'm upgrading from Laravel 7 to 8 and would like to switch to barryvdh/laravel-dompdf for PDF generation. I was using niklasravnsborg/laravel-pdf up until now, but since that package doesn't support Laravel 8, I need to switch. So I am in the processing of altering my existing code to use barryvdh/laravel-dompdf, but I'm running into an issue.
This is my (simplified) controller:
public function update(Request $request) {
$invoice = Invoice::find($request->invoice_id);
if(isset($request->export) AND $request->export == 1) {
$this->exportInvoice($invoice, $request);
}
}
This exportInvoice function is in the same controller file.
I'm using this to generate a test PDF:
$pdf = App::make('dompdf.wrapper');
$pdf->loadHTML('<h1>Test</h1>');
return $pdf->stream();
Now I've managed to narrow down the issue to the place in my code where the PDF generation fails.
If I put the PDF generation code in the if statement in the update function above, then I get the expected result: a simple PDF file.
However, as soon as I move this piece of code to the exportInvoice function, I get a simple blank web page.
I've been googling around, but I was unable to find similar issues.
I've tried putting all my code together in the update function and guess what ... This works as expected. It's as if I'm doing something wrong with the subfunctions, but I can't figure out what.
Does anybody see what I'm doing wrong?

Answer 1

From your update() method, this will stream a PDF back to the browser:
return $pdf->stream();
But from a exportInvoice(), called by the update() method, that will just return the stream back to the update() method. If you don't do anything with it there, it won't reach the browser. You need to return the response returned from exportInvoice().
public function update(Request $request) {
$invoice = Invoice::find($request->invoice_id);
if(isset($request->export) AND $request->export == 1) {
// Note we need to *return* the response to the browser
return $this->exportInvoice($invoice, $request);
}
}
public function exportInvoice($invoice, $request) {
$pdf = App::make('dompdf.wrapper');
$pdf->loadHTML('<h1>Test</h1>');
return $pdf->stream();
}