Zip Download (module for Omeka S)

New versions of this module and support for Omeka S version 3.0 and above are available on GitLab, which seems to respect users and privacy better than the previous repository.

Zip Download is a module for Omeka S that allows visitors to download resource files as zip archives. Files are streamed instantly in real-time without server storage. A confirmation dialog shows the file size before downloading.

Installation

See general end user documentation for installing a module.

The module requires the module Common, version 3.4.74 or later.

For zip streaming (multiple files), PHP 8.1+ and the library maennchen/zipstream-php v3 are required (installed via Composer).

• From the zip

Download the last release ZipDownload.zip from the list of releases, and uncompress it in the modules directory.

• From the source and for development

If the module was installed from the source, rename the name of the folder of the module to ZipDownload, go to the root of the module, and run:

composer install --no-dev

• For test

The module includes a test suite with unit and functional tests. Run them from the root of Omeka:

vendor/bin/phpunit -c modules/ZipDownload/phpunit.xml --testdox

Quick start

The module provides: - A view helper downloadZip() to display download links in themes - A resource page block layout for the resource pages - Site settings to configure download behavior

Important: Download is disabled by default for security reasons. Enable it in site settings before the download button appears.

Configuration

Site settings allow to configure:

• Enable download zip: Must be checked to enable the feature (default: disabled). Unauthorized download attempts are logged.
• Download content: Download primary media only or all media files (zip archive)
• File type: Original, large, medium, or square thumbnails
• Single file as native: When enabled, single files are delivered as native files instead of zip archives
• Download element: Use a button (default, recommended) to avoid scraping by bots, or a link for better accessibility
• Maximum resources: Limit the number of resources for batch downloads (default: 25). Used when downloading multiple resources via API query.
• Copyright text: Text included in a COPYRIGHT.txt file inside the zip, with placeholders:
• {dcterms:creator}, {dcterms:date}: Resource metadata (any property)
• {file_count}, {resource_count}: Counts
• {citation}: Auto-generated citation
• {resource_id}, {resource_title}, {resource_url}: Resource info
• {site_title}, {site_url}, {main_title}: Site/installation info
• {date}, {datetime}: Download date

If zipdownload_text is empty, no COPYRIGHT.txt is added to the zip and the partials are not rendered.

Copyright text rendering (theme partials)

The COPYRIGHT.txt file added inside the zip is rendered through three phtml partials. Themes can override any of them to customize the layout:

• view/common/zip-download-copyright.phtml: single resource download.
• view/common/zip-download-copyright-multiple.phtml: batch (query) download.
• view/common/zip-download-citation.phtml: bibliographic citation, included in the {citation} placeholder of the two partials above.

The default partials simply apply strtr($zipdownloadText, $placeholders). A custom theme partial can mix the admin-configured text with hard-coded layout, or ignore the site setting entirely and produce the text from the provided variables.

Resource page blocks

Download Zip

Display a download button that allows visitors to download all resource files as a zip archive. When clicked, a confirmation dialog shows the file size.

Download Primary Media

Display a simple download button for the primary media file only. This resource block was previously included in module Block Plus.

Theme view helper

The view helper downloadZip() displays a download link for resource files with a confirmation dialog showing the file size.

The helper accepts either a single resource or an API query array to download multiple resources at once.

// Basic usage with a single resource.
echo $this->downloadZip($resource);

// With custom options for a single resource.
echo $this->downloadZip($resource, [
    // 'primary' or 'all' (default).
    'content' => 'all',
    // 'original', 'large', 'medium', 'square'.
    'type' => 'original',
    // true to output single file without zip.
    'single_as_file' => false,
    // 'button' (default, for security) or 'link'.
    'tag' => 'button',
    // Custom button label.
    'label' => 'Download files',
    // Additional CSS classes.
    'class' => 'my-class',
]);

// Download multiple resources via api query:
echo $this->downloadZip(['resource_class_id' => 5]);

// Query with specific resource type (item or media).
echo $this->downloadZip(['resource_class_id' => 5], [
    // 'items' (default) or 'media'.
    'resource_type' => 'media',
]);

// Query with property filter
echo $this->downloadZip(
    [
        'property' => [
            ['property' => 'dcterms:subject', 'type' => 'eq', 'text' => 'art'],
        ],
    ],
    [
        'type' => 'large',
        'label' => 'Download collection',
    ]
);

When using a query, the helper respects the site setting zipdownload_max (default: 25) to limit the number of resources. The query is automatically constrained to the current site. Files are organized in folders by resource inside the zip archive.

TODO

• [ ] Add a limit by collection to forbid zipping some items or media, or file types.

Warning

Use it at your own risk.

It’s always recommended to backup your files and your databases and to check your archives regularly so you can roll back if needed.

# database dump example
mariadb-dump -u omeka -p omeka | gzip > "omeka.$(date +%Y%m%d_%H%M%S).sql.gz"

Troubleshooting

See online issues on the module issues page on GitLab.

License

This module is published under the CeCILL v2.1 license, compatible with GNU/GPL and approved by FSF and OSI.

This software is governed by the CeCILL license under French law and abiding by the rules of distribution of free software. You can use, modify and/ or redistribute the software under the terms of the CeCILL license as circulated by CEA, CNRS and INRIA at the following URL "http://www.cecill.info".

As a counterpart to the access to the source code and rights to copy, modify and redistribute granted by the license, users are provided only with a limited warranty and the software's author, the holder of the economic rights, and the successive licensors have only limited liability.

In this respect, the user's attention is drawn to the risks associated with loading, using, modifying and/or developing or reproducing the software by the user in light of its specific status of free software, that may mean that it is complicated to manipulate, and that also therefore means that it is reserved for developers and experienced professionals having in-depth computer knowledge. Users are therefore encouraged to load and test the software's suitability as regards their requirements in conditions enabling the security of their systems and/or data to be ensured and, more generally, to use and operate it in the same conditions as regards security.

The fact that you are presently reading this means that you have had knowledge of the CeCILL license and that you accept its terms.

Copyright

• Copyright Daniel Berthereau, 2021-2026 (see Daniel-KM on GitLab)

This module was designed for Explore PSL and Musée de Bretagne.