1. The Hydra Framework as a Series of Diagrams Naomi Dushay Stanford University Libraries April, 2012 1

2. High Level (Rough Conceptual) Solr Create, Update, Delete (any) Solr Index Fedora Object Storage Solr Index of Stored Objects UI Layer: Ruby on Rails Back End Blacklight for Stored Objects Read Blacklight Hydra 2

3. Ruby on Rails Views: UI presentation Controllers: UI flow of control Models: interface to stored data SQL database Views Models Controllers Data storage Rails is a Ruby gem that provides an MVC framework for writing web applications 3

4. Blacklight Gem Views: UI presentation Controllers: UI flow of control Models: interface to stored data SQL database Views Models Controllers Data storage Solr Blacklight Solr is external to Blacklight, but required (much as a SQL database is required for a Ruby-on-Rails application) Blacklight is a Ruby-on-Rails gem that provides a web discovery interface for a Solr index 4

5. Your Data Your Blacklight Application Your SQL database Views Models Controllers Your Solr Blacklight Your Rails Application 5

6. High Level (Rough Conceptual, again) Solr Create, Update, Delete (any) Solr Index Fedora Object Storage Solr Index of Stored Objects UI Layer: Ruby on Rails Back End Blacklight Leveraged for Stored Objects Read Blacklight Hydra 6

7. HydraHead Gem – part 1 Views Controllers Solr Fedora HydraHead is a Ruby-on-Rails gem that provides a web interface for creating, updating, and deleting Fedora objects. Models HydraHead Your Data in Fedora 7

8. SQL database HydraHead Gem – part 2 Views Controllers Solr Fedora HydraHead utilizes the Blacklight gem for the UI pieces related to discovery (i.e. read only) Models Blacklight HydraHead 8

9. Your SQL database Your Hydra Head/Application – part 1 Your Data Views Models Controllers Your Solr Blacklight Your Rails Application Your Fedora HydraHead 9

10. Models ActiveFedora Gem - part 1 Views: UI presentation Controllers: UI flow of control Model Logic Implementation SQL database Views Controllers Fedora Data storage ActiveFedora is akin to the ActiveRecord gem in a Rails application – it provides the implementation of the logic between the models and the data storage. ActiveFedora Models: which data, which behaviors ActiveRecord 10

11. Models HydraHead Gem – part 3 Views Controllers Fedora ActiveFedora HydraHead HydraHead utilizes the ActiveFedora gem to interact with Fedora 11

12. Solrizer and Rubydora Gems Solr Fedora Ruby access to Rest API External Application Solrizer Rubydora The Solrizer and Rubydora gems allow Ruby access to the Rest APIs for Solr and Fedora Rest API 12

13. Solrizer-Fedora Gem Solr Fedora Ruby access to Rest API External Application Solrizer Rubydora Solrizer-Fedora extends the Solrizer gem to work with Fedora objects. Rest API Solrizer- Fedora 13

14. Models ActiveFedora Gem – part 2 Views Controllers ActiveFedora Solr Fedora Solrizer- Fedora Rubydora Solrizer ActiveFedora utilizes Rubydora to interact with Fedora and Solrizer-Fedora to keep Solr in sync with Fedora. The Solrizer-Fedora gem extends Solrizer gem. 14

15. Models HydraHead Gem – part 4 Views Controllers ActiveFedora Solr Fedora Solrizer- Fedora Rubydora Solrizer HydraHead requires ActiveFedora which in turn requires additional Hydra framework gems HydraHead 15

16. OM Gem Solr XML data XML Ruby access to Rest API OM Solrizer OM (Opinionated Metadata) eases translation between raw XML and ruby objects. OM also provides a way to map the resulting ruby object data into Solr. 16

17. Models OM and ActiveFedora (Simplified) Solr Views Controllers Fedora datastreams can have XML content OM can be used to parse XML datastream content and map the content to Solr. The OM mappings become part of the ActiveFedora data models. OM ActiveFedora XML datastream content XML datastream content 17

18. Models ActiveFedora Gem – part 2 (again) Views Controllers ActiveFedora Solr Fedora Solrizer- Fedora Rubydora Solrizer No XML content, so no use of OM gem 18

19. Hydra Backend Gems Solr Fedora Views Controllers XML datastream content XML datastream content OM Solrizer Solrizer- Fedora ActiveFedora Rubydora Updates to Fedora content must be reflected in both Solr and Fedora Models 19

20. SQL database Models HydraHead Gem – part 5 Solr Fedora Views Controllers Solrizer Solrizer- Fedora ActiveFedora Rubydora Blacklight HydraHead HydraHead is a Ruby- on-Rails gem that utilizes the Blacklight gem to read and display Solr documents, the ActiveFedora gem to express Fedora objects in Ruby, the Solrizer- Fedora gem for ease of syncing Fedora and Solr, and other gems and their dependencies as needed. 20

21. Rubydora Your SQL database Models Your Solr Views Controllers Solrizer Solrizer- Fedora ActiveFedora Your Hydra Head/Application – part 2 Your Data Your Fedora Blacklight HydraHead Your Rails Application 21

22. (Rubydora) Solrizer Solrizer-Fedora OM ActiveFedora HydraHead (Used, by not maintained by Hydra Community: Blacklight, Solr, Fedora, …) Core Hydra-Framework Code maintained by the Hydra Community 22

23. Hydra-Jetty JettyWrapper Additional Hydra-Framework Code maintained by the Hydra Community 23

24. Jetty – Java Web Server and Servlet Container Hydra-Jetty Jetty with Solr and Fedora pre-installed Ruby – start/stop jetty, etc. (convenient for automated testing) Jetty: Java Web Server and Servlet Container (note that Solr and Fedora are both written in java and utilize java servlets) JettyWrapper 24

25. One Possible Backend Configuration Hydra-Jetty Solr Fedora Rest API Solr and Fedora can be in the same web application or separate web applications. Solr is also implemented in Ruby and other languages, so it doesnt need to be in a 25

26. Solrizer Solrizer- Fedora Rubydora Your SQL database Hydra-Jetty Your Solr ActiveFedora Your Hydra Head/Application using Hydra-Jetty Your Data Your Fedora Models Views Controllers Blacklight HydraHead Your Rails Application 26