BookStackApp/BookStack · error · PdfExportException

PDF Export via command failed, PDF output file is empty

Error message

PDF Export via command failed, PDF output file is empty

What it means

PdfExportException thrown in PdfGenerator::renderUsingCommand after the external PDF command (e.g. weasyprint/puppeteer script) exited successfully but the produced output file was empty or unreadable via file_get_contents, meaning rendering silently produced no PDF. Typically indicates a broken/unsupported export command install.

Source

Thrown at app/Exports/PdfGenerator.php:174

        try {
            $process->run();
        } catch (ProcessTimedOutException $e) {
            $cleanup();
            throw new PdfExportException("PDF Export via command failed due to timeout at {$timeout} second(s)");
        }

        if (!$process->isSuccessful()) {
            $cleanup();
            throw new PdfExportException("PDF Export via command failed with exit code {$process->getExitCode()}, stdout: {$process->getOutput()}, stderr: {$process->getErrorOutput()}");
        }

        $pdfContents = file_get_contents($outputPdf);
        $cleanup();

        if ($pdfContents === false) {
            throw new PdfExportException("PDF Export via command failed, unable to read PDF output file");
        } else if (empty($pdfContents)) {
            throw new PdfExportException("PDF Export via command failed, PDF output file is empty");
        }

        return $pdfContents;
    }

    protected function renderUsingWkhtml(string $html): string
    {
        $snappy = new SnappyPdf($this->getWkhtmlBinaryPath());
        $options = config('exports.snappy.options');
        return $snappy->getOutputFromHtml($html, $options);
    }

    /**
     * Taken from https://github.com/barryvdh/laravel-dompdf/blob/v2.1.1/src/PDF.php
     * Copyright (c) 2021 barryvdh, MIT License
     * https://github.com/barryvdh/laravel-dompdf/blob/v2.1.1/LICENSE
     */
    protected function convertEntities(string $subject): string

View on GitHub (pinned to 18f8469a1c)

Solutions

1. Verify the configured PDF command binary is installed and a working version
2. Run the export command manually against a test HTML file to see its stdout/stderr
3. Check temp-directory permissions so the command can write its output file
4. Update or reinstall the PDF rendering tool

When it happens

Trigger: Thrown at app/Exports/PdfGenerator.php:174 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BookStackApp/BookStack@18f8469a1c (2026-09-02). Data as JSON: /api/errors/700719572c1cb7b4. Report an issue: GitHub.