IIIFManifest

IIIF http://iiif.io/ defines an API for presenting related images in a viewer. This transforms Hydra::Works objects into that format usable by players such as http://universalviewer.io/

Usage

Your application must have an object that implements #file_set_presenters and #work_presenters. The former method should return as set of leaf nodes and the later any interstitial nodes. If none are found an empty array should be returned.

Additionally, it must have a #description method that returns a string.

Additionally it should implement #manifest_url that shows where the manifest can be found.

Additionally it should implement #manifest_metadata to provide an array containing hashes of metadata Label/Value pairs.

Additionally it may implement #search_service to contain the url for an IIIF search api compliant search endpoint and #autocomplete_service to contain the url for an IIIF search api compliant autocomplete endpoint. Please note, the autocomplete service is embedded within the search service description so if an autocomplete_service is supplied without a search_service it will be ignored. The IIIF profile added to the service descriptions is version 0 as this is the version supported by the current version of Universal Viewer. Only include a search_service within the manifest if your application has impelmented an IIIF search service at the endpoint specified in the manifest.

Additionally it may implement #sequence_rendering to contain an array of hashes for file downloads to be offered at sequences level. Each hash must contain "@id", "format" (mime type) and "label" (eg. { "@id" => "download url", "format" => "application/pdf", "label" => "user friendly label" }).

Finally, It may implement ranges, which returns an array of objects which represent a table of contents or similar structure, each of which responds to label, ranges, and file_set_presenters.

For example:

 class Book
   def initialize(id, pages = [])
     @id = id
     @pages = pages
   end

   def file_set_presenters
     @pages
   end

   def work_presenters
     []
   end

   def manifest_url
     "http://test.host/books/#{@id}/manifest"
   end

   def description
     'a brief description'
   end

   def manifest_metadata
         [
           { "label" => "Title", "value" => "Title of the Item" },
           { "label" => "Creator", "value" => "Morrissey, Stephen Patrick" }
         ]
   end

   def search_service
     "http://test.host/books/#{@id}/search"
   end

   def autocomplete_service
     "http://test.host/books/#{@id}/autocomplete"
   end

   def sequence_rendering
     [{"@id" => "http://test.host/file_set/id/download", "format" => "application/pdf", "label" => "Download"}]
   end

   def ranges
     [
       ManifestRange.new(
         label: "Table of Contents",
         ranges: [
           ManifestRange.new(
             label: "Chapter 1",
             file_set_presenters: @pages
           )
         ]
       )
     ]
   end
 end

 class ManifestRange
   attr_reader :label, :ranges, :file_set_presenters
   def initialize(label:, ranges: [], file_set_presenters: [])
     @label = label
     @ranges = ranges
     @file_set_presenters = file_set_presenters
   end
 end

The class that represents the leaf nodes, must implement #id. It must also implement #display_image which returns an instance of IIIFManifest::DisplayImage

  class Page
    def initialize(id)
      @id = id
    end

    def id
      @id
    end

    def display_image
      IIIFManifest::DisplayImage.new(id,
                                     width: 100,
                                     height: 100,
                                     format: "image/jpeg",
                                     iiif_endpoint: endpoint
                                     )
    end

    private

      def endpoint
        IIIFManifest::IIIFEndpoint.new("http://test.host/images/#{id}",
                                       profile: "http://iiif.io/api/image/2/level2.json")
      end
  end

Then you can produce the manifest on the book object like this:

  book = Book.new('book-77',[Page.new('page-99')])
  IIIFManifest::ManifestFactory.new(book).to_h.to_json

Presentation 3.0 (Alpha)

Provisional support for the 3.0 alpha version of the IIIF presentation api spec has been added with a focus on audiovisual content. The change log lists the changes to the specification.

The presentation 3.0 support has been contained to the V3 namespace. Version 2.0 manifests are still be built using IIIFManifest::ManifestFactory while version 3.0 manifets can now be built using IIIFManifest::V3::ManifestFactory.

  book = Book.new('book-77',[Page.new('page-99')])
  IIIFManifest::V3::ManifestFactory.new(book).to_h.to_json

Notable changes for Presentation 3.0

• Presenters must still define #description but it is now serialized as summary. (https://iiif.io/api/presentation/3.0/change-log/#126-rename-description-to-summary)
• All textual strings, including metadata labels and values, are now serialized as language maps and may be provided as a hash with language code keys with string values. Values not provided in this format are automatically converted so no change to #description, #manifest_metadata, range labels, or other fields are required. (https://iiif.io/api/presentation/3.0/change-log/#133-use-language-map-pattern-for-label-value-summary)
• File set presenters may target a fragment of its content by providing #media_fragment which will be appended to its id.
• Range objects may now implement #items instead of #ranges and #file_set_presenters to allow for interleaving these objects. #items is not required and existing range objects should continue to work.
• File set presenters may provide #display_content which should return an instance of IIIFManifest::V3::DisplayContent (or an array of instances in the case of a user Choice). #display_image is no longer required but will still work if provided.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/samvera-labs/iiif_manifest. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.