BookStackApp/BookStack · error · ZipExportException

errors.import_zip_data_too_large

Error message

errors.import_zip_data_too_large

What it means

ZipExportReader::readData() throws 'errors.import_zip_data_too_large' when the uncompressed size of the embedded data.json exceeds the application's configured upload limit (config('app.upload_limit') in megabytes, minimum 1). BookStack refuses to decode oversized import payloads to protect memory. This happens before json_decode runs.

Source

Thrown at app/Exports/ZipExports/ZipExportReader.php:68

            $this->open = false;
        }
    }

    /**
     * @throws ZipExportException
     */
    public function readData(): array
    {
        $this->open();

        $info = $this->zip->statName('data.json');
        if ($info === false) {
            throw new ZipExportException(trans('errors.import_zip_cant_decode_data'));
        }

        $maxSize = max(intval(config()->get('app.upload_limit')), 1) * 1000000;
        if ($info['size'] > $maxSize) {
            throw new ZipExportException(trans('errors.import_zip_data_too_large'));
        }

        // Validate json data exists, including metadata
        $jsonData = $this->zip->getFromName('data.json') ?: '';
        $importData = json_decode($jsonData, true);
        if (!$importData) {
            throw new ZipExportException(trans('errors.import_zip_cant_decode_data'));
        }

        return $importData;
    }

    public function fileExists(string $fileName): bool
    {
        return $this->zip->statName("files/{$fileName}") !== false;
    }

    public function fileWithinSizeLimit(string $fileName): bool

View on GitHub (pinned to 18f8469a1c)

Solutions

1. Raise 'upload_limit' in config/app.php (or APP_UPLOAD_LIMIT env) to exceed the data.json size in MB, then clear config caches (php artisan config:clear).
2. Split the export into smaller books/chapters on the source instance.
3. Confirm with `unzip -l export.zip` how large data.json is and set the limit accordingly.
4. If the limit won't budge, import content manually via the API instead.

Example fix

// before (.env)
APP_UPLOAD_LIMIT=10
// after
APP_UPLOAD_LIMIT=200

$zip = new ZipArchive();
$zip->open($path);
$stat = $zip->statName('data.json');
$limitMb = max((int) config('app.upload_limit'), 1);
if ($stat !== false && $stat['size'] > $limitMb * 1000000) {
    throw new \RuntimeException("data.json is {$stat['size']} bytes; exceeds {$limitMb}MB upload limit");
}

try {
    $model = $reader->decodeDataToExportModel();
} catch (\BookStack\Exports\ZipExports\ZipExportException $e) {
    report($e); // surface which limit was hit
    // raise APP_UPLOAD_LIMIT or split the export
}

When it happens

Trigger: Importing a BookStack ZIP export whose data.json 'size' from statName() is greater than max(app.upload_limit,1) * 1000000 bytes — i.e. large exports with many pages/attachments metadata.

Common situations: Very large book/chapter exports from a big instance; app.upload_limit left at default (e.g. 10 or unset/0) while the export is larger; PHP memory limits also being tight on shared hosting.

Understand the failure class

Background: "File too large" / "file size exceeds limit" errors: why libraries cap file sizes and how to fix them — this error's family across 46 libraries.

Related errors

• File $fileName exceeds app upload limit.
• errors.import_zip_cant_decode_data
• Could not identify content in ZIP file data.
• errors.import_validation_failed
• Must not have a parent set for a Book import.

AI-assisted analysis of BookStackApp/BookStack@18f8469a1c (2026-09-02). Data as JSON: /api/errors/3354c0613315fad6. Report an issue: GitHub.