Riiif

A Ruby IIIF image server as a rails engine

Installation

Add this line to your application's Gemfile:

gem 'riiif'

And then execute:

$ bundle

Or install it yourself as:

$ gem install riiif

Configure

Images on the servers file system.

By default Riiif is set to load images from the filesystem using the Riiif::FileSystemFileResolver. You can configure how this resolver finds the files by setting this property:

    Riiif::FileSystemFileResolver.base_path = '/opt/repository/images/'

When the Id passed in is "foo_image", then it will look for an image file using this glob:

/opt/repository/images/foo_image.{png,jpg,tiff,jp,jp2}

Images retrieved over HTTP

It's preferable to use files on the filesystem, because this avoids the overhead of downloading the file. If this is unavoidable, Riiif can be configured to fetch files from the network. To enable this behavior, configure Riiif to use an alternative resolver:

      Riiif::Image.file_resolver = Riiif::HTTPFileResolver

Then we configure the resolver with a mechanism for mapping the provided id to a url:

      Riiif::HTTPFileResolver.id_to_uri = lambda do |id| 
        "http://upload.wikimedia.org/wikipedia/commons/thumb/a/a4/#{id}.jpg/600px-#{id}.jpg"
      end

This file resolver caches the network files, so you will want to clear out the old files or the cache will expand until you run out of disk space. Using a script like this would be a good idea: https://github.com/pulibrary/loris/blob/607567b921404a15a2111fbd7123604f4fdec087/bin/loris-cache_clean.sh By default the cache is located in tmp/network_files. You can set the cache path like this: Riiif::HTTPFileResolver.cache_path = '/var/cache'

Usage

Mount the gem as an engine:

mount Riiif::Engine => '/image-service'

Then you can make requests like this:

OpenSeadragon

Riiif ships with OpenSeaDragon support. To use it add this in your controller:

helper Riiif::OpenseadragonHelper

Then in your view you can do this:

    <%=javascript_include_tag "openseadragon.js" %>
    <%= openseadragon_viewer(@image.id, html: {style: 'width: 800px; height: 600px;'}) %>

For more information

see the IIIF spec:

http://www-sul.stanford.edu/iiif/image-api/1.1/