Skip to content
master
Go to file
Code

README.md

IIIF Server (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.

Build Status

IMPORTANT: This readme is for the development version of IIIF Server. See stable version here. This new version is working, but requires the module Image Server.

IIIF Server is a module for Omeka S that integrates the IIIF specifications to allow to process and share instantly images of any size and medias (pdf, audio, video, 3D…) in the desired formats. It requires an image server, like the module Image Server.

The full specifications of the International Image Interoperability Framework standard are supported (level 2), so any widget that supports it can use it. Rotation, zoom, inside search, etc. may be managed too. Dynamic lists of records may be created, for example for browse pages.

This Omeka S module is a rewrite of the Universal Viewer plugin for Omeka by BibLibre with the same features as the original plugin, but separated into two modules (the IIIF server and the widget Universal Viewer). It integrates the tiler Zoomify that was used the plugin OpenLayers Zoom for Omeka Classic and another tiler to support the Deep Zoom Image tile format.

The IIIF manifests can be displayed with many viewers, the integrated OpenSeadragon, the Universal Viewer, the advanced Mirador, or the ligher and themable Diva, or any other IIIF compatible viewer.

The search is provided by the module Iiif Search for common xml formats.

Installation

Module

Installation can be done:

  • From the zip

Download the last release IiifServer.zip from the list of releases (the master does not contain the dependencies), uncompress it in the modules directory, and rename the module folder IiifServer.

  • From the source and for development:

If the module was installed from the source, check if the name of the folder of the module is IiifServer, go to the root of the module, and run:

composer install --no-dev

Then install it like any other Omeka module.

Note: To keep old options from Universal Viewer, upgrade it to version 3.4.3 before enabling of IiifServer. Else, simply set them in the config form.

Image server

An image server is required to display the images. It can be the module Image Server, or any other IIIF compliant image server. The image server is used to display audio and video files too.

PHP

PHP should be installed with the extension exif in order to get the size of images. This is the case for all major distributions and providers. At least one of the php extensions GD or Imagick are recommended. They are installed by default in most servers. If not, the image server will use the command line ImageMagick tool convert automatically.

Web server and identifiers containing /

This point is related to Apache. If you are using nginx, you can skip it.

If you are using Ark as identifier for items and IIIF manifests (through the modules Clean Url and optionally Ark), or any other identifier that contains a forward slash /, you must modify the Apache system configuration, because by default, it doesn't allow the url encoded / (%2F) inside urls for an old security issue.

Indeed, an Ark identifier contains at least two forward slashes / (ark:/12345/bNw3sx) and the IIIF specification requires to use url encoded slashes, except for the colon : (ark:%2F12345%2FbNw3sx). More precisely, this iiif requirement is specified in the Image Api, not in the presentation Api, but the identifiers are used in the same way.

AllowEncodedSlashes NoDecode

If you cannot access to config of the server, two settings can fix it in the config of the module :

  • disable the advanced option "Use the identifiers from Clean Url";
  • set the "Prefix to use for identifier".

Notes

The module allows to manage collections (item set level/item list), and manifests (item level). The info.json (media level) are managed by the image server.

Using externally supplied IIIF manifest

If you are harvesting data (via OAI-PMH, for instance) from another system where images are hosted and exposed via IIIF, you can use a configurable metadata field to supply the manifest to the viewer (Universal Viewer, Mirador or Diva). In this case, no images are hosted in the Omeka record, but one of the metadata fields has the URL of the manifest hosted on another server.

For example, you could set the alternative manifest element to "Dublin Core:Has Format" in the module configuration, and then put a URL like "https://example.com/iiif/HI-SK20161207-0009/manifest" in the specified element of a record. The viewer included on that record’s display page will use that manifest URL to retrieve images and metadata for the viewer.

Using a third-party IIIF Image server via the Omeka media type "IIIF Image"

If your images are already managed by one or multiple dedicated third-party image server (for instance one of the software listed in the official list of the IIIF community), you can use them directly in your items: create or import them as media "IIIF Image". With this media type, the full json is saved in metadata of the media itself.

If you don’t want to manage a dedicated image server, you can simply install the module Image Server.

Customize data of manifests

The module creates manifests with all the metadata of each record. The event iiifserver.manifest can be used to modify the exposed data of a manifest for items, collections, collection lists (search results) and media (info.json). So, it is possible, for example, to modify the citation, to remove or to add some metadata or to change the thumbnail.

Note: with a collection list, the parameter resource is an array of resources.

All the combinations are possible: external manifest for items, iiif image for external medias, a local standard media file with module Image Server.

Routes and urls

All routes of the IIIF server are defined in config/module.config.php. They follow the recommandations of the IIIF specifications.

To view the json-ld manifests created for each resources of Omeka S, simply try these urls (replace :id by a true id):

By default, ids are the internal ids of Omeka S, but it is recommended to use your own single and permanent identifiers that don’t depend on an internal pointer in a database. The term Dublin Core Identifier is designed for that and a record can have multiple single identifiers. There are many possibilities: named number like in a library or a museum, isbn for books, or random id like with ark, noid, doi, etc. They can be displayed in the public url with the modules Ark and/or Clean Url.

3D models

The creation of manifests for 3D models is fully supported by the widget and natively managed since the release 2.3 of Universal Viewer via the threejs library. The other viewers integrated in Omeka doesn’t support 3D.

  • Possible requirement

The module Archive Repertory must be installed when the json files that represent the 3D models use files that are identified by a basename and not a full url. This is generally the case, because the model contains an external image for texture. Like Omeka hashes filenames when it ingests files, the file can’t be retrieved by the Universal Viewer.

This module is not required when there is no external images or when these images are referenced in the json files with a full url.

To share the json with other IIIF servers, the server may need to allow CORS (see above).

Important: When using Archive Repertory and when two files have the same base name (here "thekiss.jpg" and "thekiss.json"), the image, that is referenced inside the json, must be uploaded before the json. Furthermore, the name of the thumbnail must be thumb.jpg and it is recommended to upload it first.

Finally, note that 3D models are often heavy, so the user has to wait some seconds that the browser loads all files and prepares them to be displayed.

TODO / Bugs

  • Implements ArrayObject to all classes to simplify events.
  • When a item set contains non image items, the left panel with the index is displayed only when the first item contains an image (UV).
  • Use the option "no storage" for url of a media for external server.
  • Job to update data of IIIF Image.
  • Use only arrays, not standard objects.
  • Manage url prefix.

See module Image Server.

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.

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.

In consideration of access to the source code and the 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 only have limited liability.

In this respect, the risks associated with loading, using, modifying and/or developing or reproducing the software by the user are brought to the user’s attention, given its Free Software status, which may make it complicated to use, with the result that its use is reserved for developers and experienced professionals having in-depth computer knowledge. Users are therefore encouraged to load and test the suitability of the software 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 of security.

This Agreement may be freely reproduced and published, provided it is not altered, and that no provisions are either added or removed herefrom.

Copyright

  • Copyright Daniel Berthereau, 2015-2020 (see Daniel-KM)
  • Copyright BibLibre, 2016-2017
  • Copyright Régis Robineau, 2019 (see regisrob)

First version of this plugin was built for the Bibliothèque patrimoniale of Mines ParisTech.

About

IIIF Server is a module for Omeka S that adds the IIIF specifications to serve any images and medias.

Topics

Resources

License

Packages

No packages published

Languages

You can’t perform that action at this time.