BookStackApp/BookStack · error · ZipExportException

Could not identify content in ZIP file data.

Error message

Could not identify content in ZIP file data.

What it means

ZipExportReader::decodeDataToExportModel() inspects the decoded data.json for one of the keys 'book', 'chapter', or 'page' (after handling meta) and builds the matching ZipExport* model. If none of these keys is present it throws a plain ZipExportException with the literal message 'Could not identify content in ZIP file data.' — the archive is valid JSON but not a recognized BookStack export payload.

Source

Thrown at app/Exports/ZipExports/ZipExportReader.php:130

        return (new WebSafeMimeSniffer())->sniff($sniffContent);
    }

    /**
     * @throws ZipExportException
     */
    public function decodeDataToExportModel(): ZipExportBook|ZipExportChapter|ZipExportPage
    {
        $data = $this->readData();
        if (isset($data['book'])) {
            return ZipExportBook::fromArray($data['book']);
        } else if (isset($data['chapter'])) {
            return ZipExportChapter::fromArray($data['chapter']);
        } else if (isset($data['page'])) {
            return ZipExportPage::fromArray($data['page']);
        }

        throw new ZipExportException("Could not identify content in ZIP file data.");
    }
}

View on GitHub (pinned to 18f8469a1c)

Solutions

1. Open data.json and confirm it has a top-level 'book', 'chapter', or 'page' key.
2. Regenerate the export from BookStack's export UI/command so the schema matches.
3. Fix key names if the file was hand-crafted (singular 'book'/'chapter'/'page', not plural).
4. Check BookStack version compatibility — export/import schema changed between major versions.

Example fix

// before (data.json)
{"meta": {...}, "books": {...}}
// after
{"meta": {...}, "book": {"id": 1, "name": "My Book", ...}}

$data = json_decode($zip->getFromName('data.json') ?: '', true);
if (!isset($data['book'], $data['chapter'], $data['page'])) {
    // at least one must be set
    if (empty(array_intersect(['book','chapter','page'], array_keys($data ?: [])))) {
        throw new \RuntimeException('data.json has no book/chapter/page key');
    }
}

function hasRecognizedExportContent(?array $data): bool {
    return is_array($data) && (isset($data['book']) || isset($data['chapter']) || isset($data['page']));
}

try {
    $model = $reader->decodeDataToExportModel();
} catch (\BookStack\Exports\ZipExports\ZipExportException $e) {
    if ($e->getMessage() === 'Could not identify content in ZIP file data.') {
        // inspect top-level keys of data.json
    }
}

When it happens

Trigger: data.json decodes fine but contains none of the keys book/chapter/page at the top level (e.g. only {"meta":...}, an empty array passed the earlier falsy check, or a differently structured JSON).

Common situations: Importing a ZIP from another tool; a data.json that was trimmed to only metadata; a future/older export schema mismatch; manually crafted import files using wrong key names (e.g. 'books' or 'pages' plural).

Related errors

• errors.import_zip_cant_decode_data
• errors.import_zip_data_too_large
• errors.import_validation_failed
• Must not have a parent set for a Book import.
• Parent book required for chapter import.

AI-assisted analysis of BookStackApp/BookStack@18f8469a1c (2026-09-02). Data as JSON: /api/errors/059dee638a469a69. Report an issue: GitHub.