ActiveAnnotations
ActiveAnnotations is a gem for modeling simple OpenAnnotation-compatible annotations to Rails. It is ActiveRecord compatible, but is backed by an RDF graph that serializes (by default) to JSON-LD.
- The
source_uri
and the serialized annotation are stored in ActiveRecord; other methods access the underlying graph. - All attributes are optional.
- Target selectors are currently limited to time-based media fragments, but will be generalized in future iterations.
- If using v1.x of the
rdf
gem, all DateTime values must be in UTC to ensure proper serialization. This restriction does not apply tordf >= 2.0
.
Installation
Add this line to your application's Gemfile:
gem 'active_annotations'
And then execute:
$ bundle install
Run the install generator which will copy over the required migrations and run them:
$ rails generate active_annotations:install
Usage
note = ActiveAnnotations::Annotation.create
note.label = 'This is the annotation label'
note.annotated_by = 'https://github.com/mbklein/'
note.annotated_at = DateTime.now
note.content = 'The five boxing wizards jump quickly.'
note.source = thing # thing is expected to respond to :rdf_uri and :rdf_type
note.start_time = 3.5
note.end_time = 10.75
note.save
puts note.pretty_annotation
Output:
{
"@context": "http://www.w3.org/ns/oa.jsonld",
"@id": "urn:uuid:cac68351-a920-47d5-8c7c-9820e2f4d3bd",
"@type": "oa:Annotation",
"dcterms:creator": {
"@id": "https://github.com/mbklein/",
"@type": "foaf:Person"
},
"hasBody": {
"@id": "urn:uuid:55cb5e7e-19bf-406c-9e4c-cc0ff9fd0689",
"@type": [
"dctypes:Text",
"cnt:ContentAsText"
],
"chars": "The five boxing wizards jump quickly."
},
"hasTarget": {
"@id": "urn:uuid:7a5adf37-7bf2-45d4-ab0d-5a6b9aa2c6ad",
"@type": "oa:SpecificResource",
"hasSelector": {
"@id": "urn:uuid:21331f24-e065-4c06-8c7f-b42a95c53721",
"@type": "oa:FragmentSelector",
"conformsTo": "http://www.w3.org/TR/media-frags/",
"value": "t=3.5,10.75"
},
"hasSource": {
"@id": "http://www.example.edu/thing/being/annotated",
"@type": "dctypes:MovingImage"
}
},
"label": "This is the annotation label",
"dcterms:modified": {
"@value": "2016-04-22T12:59:31Z",
"@type": "xsd:dateTime"
}
}
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/avalonmediasystem/active_annotations.
License
The gem is available as open source under the terms of the Apache License.