version 8.x-1.1

Middleware Services

Islandora middleware services utilize the Fedora 4 REST API and the Drupal Services module to create an API for the majority of interactions between the two systems. The Drupal uuid will be used to identify pcdm:Objects (and pcdm:Files thereof) when using these services. The breakdown of services is as follows:

  • There will be a services to provide CRUD operations for pcdm:Collections, pcdm:Objects and pcdm:Files.
  • There will be a service to provide creational operations using zip content based on content model. For example:
  • POST a zip file containing book pages Islandora Book Batch format to create an entire book object (with pages and derivatives processed asynchronously, of course).
  • There will be services per derivative type to perform operations based on the node UUID of the parent.
  • PATCH to generate a new thumbnail for a pcdm:Object.

For more information on PCDM, please see this page.

Collection Service

Used for manipulating pcdm:Collections. Essentially wraps the Fedora 4 API requests for manipulating a Container identified by Drupal uuid. Node content in application/json format is massaged into application/sparql-update format in order to interact with Fedora.

Endpoint: http://localhost:8080/islandora-services/collection/

Actions:

  • GET http://localhost:8080/islandora-services/collection/{uuid}

    • Returns application/ld+json RDF metadata for the pcdm:Collection identified by the supplied Drupal uuid.

  • POST http://localhost:8080/islandora-services/collection/

    • Accepts application/json serialized node data.
    • Creates a pcdm:Collection in Fedora using the Drupal node data, associating the newly minted path with the node's uuid. If fedora:hasParent is supplied supplied in POST data, that location will be used to create the new object as a child.

  • PUT http://localhost:8080/islandora-services/collection/{uuid}

    • Accepts application/json serialized node data.
    • Updates metadata in Fedora for the pcdm:Collection associated with the provided Drupal uuid.

  • DELETE http://localhost:8080/islandora-services/collection/{uuid}

    • Deletes the pcdm:Collection in Fedora associated with provided Drupal uuid.

Object Service

Used for manipulating pcdm:Objects. Essentially wraps the Fedora 4 API requests for manipulating a Container identified by Drupal uuid. Node content in application/json format is massaged into application/sparql-update format in order to interact with Fedora. Certain field values, as well as other files sent along in the message will be converted into pcdm:Files and attached to the newly created pcdm:Object.

Endpoint: http://localhost:8080/islandora-services/object/

Actions:

  • GET http://localhost:8080/islandora-services/object/{uuid}

    • Returns application/ld+json RDF metadata for the pcdm:Object identified by the supplied Drupal uuid.

  • POST http://localhost:8080/islandora-services/object/

    • Accepts multipart/form-data messages. One "part" of the message will be the JSON serialized Drupal node content. Other "parts" will be files used to create pcdm:Files for the pcdm:Object.
    • Creates a pcdm:Object in Fedora using the Drupal node data, associating the newly minted path with the node's uuid. If fedora:hasParent is supplied supplied in POST data, that location will be used to create the new object as a child. Certain field values as well as any other files contained in the message will be used to create pcdm:Files associated with this pcdm:Object.

  • PUT http://localhost:8080/islandora-services/object/{uuid}

    • Accepts multipart/form-data messages. One "part" of the message will be the JSON serialized Drupal node content. Other "parts" will be files used to create pcdm:Files for the pcdm:Object.
    • Updates metadata in Fedora for the pcdm:Object associated with the provided Drupal uuid. Certain field values as well as any other files contained in the message will be used to update pcdm:Files associated with this pcdm:Object.

  • DELETE http://localhost:8080/islandora-services/object/{uuid}

    • Deletes the pcdm:Object in Fedora associated with provided Drupal uuid. Also deletes any pcdm:Files directly contained by the pcdm:Object.

File Services

Used for manipulating pcdm:Files associated with a pcdm:Object. They will essentially wrap the Fedora 4 API requests for manipulating a NonRDFSourceDescription identified by dcterms:title (obj, mods, dc, etc...) and its parent's Drupal uuid. There will be seperate implementations for each applicable dcterms:title, though each service will abide by a common conventions and behavior. This allows implementations to vary independently based on file type (technical metadata, descriptive metadata, archival binary), while allowing for new services to be easily added over time.

General Convention

Endpoint: http://localhost:8080/islandora-services/file/{uuid}/{dcterms:title} Actions:

  • GET http://localhost:8080/islandora-services/file/{uuid}/{dcterms:title}

    • Retrieves the pcdm:File content belonging to the pcdm:Object. The pcdm:File is identified by dcterms:title and its parents Drupal uuid.

  • POST http://localhost:8080/islandora-services/file/{uuid}/{dcterms:title}

    • Adds a pcdm:File to the pcdm:Object identified by the provided Drupal uuid. The file's content will be set using the POST content, and the provided dcterms:title will be given to the newly created pcdm:File.

  • PUT http://localhost:8080/islandora-services/file/{uuid}/{dcterms:title}

    • Updates the pcdm:File with dcterms:title owned by the pcdm:Object identified by the provided Drupal uuid. The file's content will be set using the PUT content.

  • DELETE http://localhost:8080/islandora-services/file/{uuid}/{dcterms:title}

    • Deletes the pcdm:File with dcterms:title owned by the pcdm:Object identified by the provided Drupal uuid.

Example Services

Some example services would include:

  • http://localhost:8080/islandora/services/file/{uuid}/obj
  • http://localhost:8080/islandora/services/file/{uuid}/dc
  • http://localhost:8080/islandora/services/file/{uuid}/mods
  • http://localhost:8080/islandora/services/file/{uuid}/fits

Implementations would differ in the sense that accept headers would be different, and data may have to be transformed differently before being inserted as the pcdm:File.

Derivative Services

Derivatives (while generally dealt with through Islandora Sync) may need to be dealt with manually, so services will be provided to handle all the common derivatives types an Islandora installation may require. Much like the file services, a general convention on naming and behavior will be enforced, but seperate implementations will be provided. This will allow for maximum flexibility and encourage new services to be easily added and contributed.

General Convention

Endpoint: http://localhost:8080/islandora-services/derivative/{uuid}/{type} Actions:

  • GET http://localhost:8080/islandora-services/derivative/{uuid}/{type}

    • Retrieves the derivative belonging to the pcdm:Object or pcdm:Collection. The derivative is identified by its type and its parents Drupal uuid.

  • POST http://localhost:8080/islandora-services/derivative/{uuid}/{type}

    • Adds a derivative to the pcdm:Object or pcdm:Collection identified by the provided Drupal uuid. The derivative's content will be set using the POST content. The result will reside in either Fedora or Drupal, depending on the derivative.

  • PUT http://localhost:8080/islandora-services/derivative/{uuid}/{type}

    • Updates the derviative for a pcdm:Object or pcdm:Collection identified by the provided Drupal uuid. The derivative's content will be set using the PUT content. The result will reside in either Fedora or Drupal, depending on the derivative.

  • PATCH http://localhost:8080/islandora-services/derivative/{uuid}/{type}

    • Asynchronously regenerates the derivative for a pcdm:Object or pcdm:Collection identified by the provided Drupal uuid. The result will reside in either Fedora or Drupal, depending on the derivative.

  • DELETE http://localhost:8080/islandora-services/derivative/{uuid}/{type}

    • Deletes the derivative for the pcdm:Object or pcdm:Collection identified by the provided Drupal uuid. The derivative will be removed from either Fedora or Drupal, depending on the derivative.

Example Services

Some example services would include:

  • http://localhost:8080/islandora/services/derivative/{uuid}/tn
  • http://localhost:8080/islandora/services/derivative/{uuid}/medium_size
  • http://localhost:8080/islandora/services/derivative/{uuid}/jp2
  • http://localhost:8080/islandora/services/derivative/{uuid}/techmd
  • http://localhost:8080/islandora/services/derivative/{uuid}/mp3
  • http://localhost:8080/islandora/services/derivative/{uuid}/mp4
  • http://localhost:8080/islandora/services/derivative/{uuid}/mkv

Implementations would differ in the sense that different derivatives will be created from varying sources using varying programs. Also, display derivatives should reside in Drupal (TN, JP2, etc...) while technical metadata should reside in Fedora. Within Drupal, different derivatives will reside as different field types.

Zip Ingest Services

Instead of multipart/form-data reqeusts, application/zip requests can be accepted to construct a pcdm:Object based on content model. While this is convienent for basic object types, it's required for more complicated content models such as Book, Newspaper, and Compound. Message bodies are assumed to be in Islandora Zip Importer format.

General Convention

Endpoint: http://localhost:8080/islandora/services/zip/ingest/{content_model}/ Actions:

  • POST http://localhost:8080/islandora/services/zip/ingest/{content_model}/
    • Accepts application/zip messages
    • Takes the supplied zip file, extracts its contents, and uses it to completely construct an object of the specified content-model.

Example services

  • http://localhost:8080/islandora/services/zip/large_image
  • http://localhost:8080/islandora/services/zip/audio
  • http://localhost:8080/islandora/services/zip/video
  • http://localhost:8080/islandora/services/zip/book
  • http://localhost:8080/islandora/services/zip/newspaper
  • http://localhost:8080/islandora/services/zip/compound