gzuncompress function returns Data Error

[zumoberhaus]

FPDI/src/PdfParser/Filter/Flate.php

Line 42 in 88a3aff

$data = (($data !== '') ? @\gzuncompress($data) : '');

The gzuncompress function returns sometimes a Data Error as explaned in the User Contributed Notes from
https://www.php.net/manual/en/function.gzuncompress.php

The workaround from the user with the gzuncompress_crc32 function works for me in these cases.

[JanSlabon]

Can you share the PDF in question? We normally already have a fallback implemented:

FPDI/src/PdfParser/Filter/Flate.php

Lines 45 to 50 in 88a3aff

	$fh = fopen('php://temp', 'w+b');
	fwrite($fh, "\x1f\x8b\x08\x00\x00\x00\x00\x00" . $oData);
	stream_filter_append($fh, 'zlib.inflate', STREAM_FILTER_READ, ['window' => 30]);
	fseek($fh, 0);
	$data = @stream_get_contents($fh);
	fclose($fh);

[zumoberhaus]

With this PDF for example it was not working for me.
https://dev.data-infrasens.ch/uploads/directaccess?token=52ec7d4a34669bb51c58c565acdaa18c5c73e8f3

[JanSlabon]

The file works without a problem and already the fallback I quoted before is used. I isolated the logic to this and all PHP versions work there, too.

What PHP version are you using? And what is the zlib version that is used? (see phpinfo() output).

[zumoberhaus]

PHP 8.0.26
zlib 1.2.7

I think, I have found a possible problem for me.
You supress the errors with "@" before the gzuncompress and then the fallback will raised.

I have a custom Error Handler implemented, which prints the warning "Warning: gzuncompress(): data error" anyway.
So my script fails, because of this output there.

Think this solves the problem for me.

[JanSlabon]

Ok, so you simply need to adjust your error handler to take care of the current error level:

function myErrorHandler($errno, $errstr, $errfile, $errline)
{
    if (!(error_reporting() & $errno)) {
        // This error code is not included in error_reporting, so let it fall
        // through to the standard PHP error handler
        return false;
    }
...