What steps can be taken to troubleshoot blank PDF generation issues with wkhtmltopdf in PHP?

Issue: If you are experiencing blank PDF generation issues with wkhtmltopdf in PHP, it could be due to missing dependencies or incorrect configurations. To troubleshoot this issue, you can check if wkhtmltopdf is properly installed, ensure that the paths are correctly set, and verify that the HTML content being passed to wkhtmltopdf is valid. 

// Check if wkhtmltopdf is properly installed
exec('which wkhtmltopdf', $output, $returnCode);
if ($returnCode !== 0) {
    die('wkhtmltopdf is not installed');
}

// Set correct paths for wkhtmltopdf and wkhtmltopdf binary
putenv('PATH=' . getenv('PATH') . ':/usr/local/bin');
putenv('WKHTMLTOPDF_BIN=/usr/local/bin/wkhtmltopdf');

// Verify HTML content is valid
$htmlContent = '<html><body><h1>Hello, World!</h1></body></html>';

// Generate PDF using wkhtmltopdf
$cmd = getenv('WKHTMLTOPDF_BIN') . ' - -';
$descriptors = [
    0 => ['pipe', 'r'],
    1 => ['pipe', 'w'],
    2 => ['pipe', 'w']
];

$process = proc_open($cmd, $descriptors, $pipes);
if (is_resource($process)) {
    fwrite($pipes[0], $htmlContent);
    fclose($pipes[0]);

    $pdfContent = stream_get_contents($pipes[1]);
    fclose($pipes[1]);

    $errorOutput = stream_get_contents($pipes[2]);
    fclose($pipes[2]);

    $returnCode = proc_close($process);

    if ($returnCode !== 0) {
        die('Error generating PDF: ' . $errorOutput);
    }

    // Output PDF
    header('Content-Type: application/pdf');
    echo $pdfContent;
} else {
    die('Error opening process');
}

Keywords

wkhtmltopdf PDF generation troubleshooting PHP blank pages

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