This app can be installed to serve as a Questioning Authority (QA) Server for accessing external authorities. It is part of a larger architecture supporting linked data authority access. See ld4l:linked_data_authorities for more information on the full architecture. From this app, you can send a search query and get back multiple results OR you can fetch a single term.

• Ruby 2.4 or the latest 2.3 version is recommended. Later versions may also work.
• Rails 5 is required. We recommend the latest Rails 5.0 release.

• clone this app from github
• run bundle install
• run rake db:migrate

• run rails s

To stop, use <ctrl><c> in the terminal window where rails s started.

There are a few authorities that are part of the QA gem. All directly access the external authority.

• direct access to OCLC FAST
  • TEST QUERY: http://localhost:3000/qa/search/linked_data/oclc_fast?q=Cornell&maximumRecords=3
  • TEST FETCH: http://localhost:3000/qa/show/linked_data/oclc_fast/2
• direct access to AGROVOC
  • TEST QUERY: http://localhost:3000/qa/search/linked_data/agrovoc?q=milk&lang=en&maxRecords=3
  • TEST FETCH: http://localhost:3000/qa/show/linked_data/agrovoc/c_9513
• direct access to Library of Congress for term fetch only
  • TEST QUERY: not supported
  • TEST FETCH: http://localhost:3000/qa/show/linked_data/loc/no2002053226

All authorities defined in ld4l-labs/linked_data_authorities are included in this repository. In your copy/fork of this app, you can remove the configuration and validation files for any authorities you do not want to support.

Configurations exist for a number of other common authorities that can be used by your QA Server. When possible, each configuration comes in two varieties...

• _AUTHORITY_NAME__direct - configuration can be used as is to access the external authority directly
• _AUTHORITY_NAME__local - configuration may require an update to the search:url:template and term:url:template to point to your local server. More information on this in ld4l-labs/linked_data_authorities

Configurations define how to access an authority and how to decode the ontology predicates to extract and convert the data to normalized data. The predefined configurations live in qa_server/config/authorities/linked_data.

If you want to access an authority for which there isn't a configuration, you can write your own. There are only two requirements to be able to access an authority.

1. For search access, the authority must have a URL API defined that accepts a string search query.
2. For term access, the authority must either support accessing the URI for the term OR provide a URL API which takes an id or URI as a parameter.
3. For both search and term, the returned results must be in a linked data format.

Instructions for writing your own configuration can be found in the (QA gem README). You are encouraged to use consistent names for common prameters, including the following...

• q - search query value that the user types
• maxRecords - to identify the max number of records for the authority to return if the authority supports limiting the number of returned records
• lang - limit string values to the identified language if the authority supports language specific requests

Add your new configuration to this_app/config/authorities/linked_data

TEST QUERY: http://localhost:3000/qa/search/linked_data/_AUTHORITY_NAME__direct?q=your_query&maxRecords=3 TEST FETCH: http://localhost:3000/qa/show/linked_data/_AUTHORITY_NAME__direct/_ID_OR_URI_

Substitute the name of the configuration file for _AUTHORITY_NAME__direct in the URL. Substitute a valid ID or URI for ID_OR_URI in the URL, as appropriate. NOTE: Some authorities expect an ID and others expect a URI.

This search query... http://localhost:3000/qa/search/linked_data/oclc_fast/personal_name?q=Cornell&maximumRecords=3

will return results like...

[{"uri":"http://id.worldcat.org/fast/5140","id":"5140","label":"Cornell, Joseph"},
 {"uri":"http://id.worldcat.org/fast/72456","id":"72456","label":"Cornell, Sarah Maria, 1802-1832"},
 {"uri":"http://id.worldcat.org/fast/409667","id":"409667","label":"Cornell, Ezra, 1807-1874"}]

This term fetch... http://localhost:3000/qa/show/linked_data/oclc_fast/530369

will return results like...

{"uri":"http://id.worldcat.org/fast/530369",
 "id":"530369","label":"Cornell University",
 "altlabel":["Ithaca (N.Y.). Cornell University","Kornelʹskii universitet","Kʻang-nai-erh ta hsüeh"],
 "sameas":["http://id.loc.gov/authorities/names/n79021621","https://viaf.org/viaf/126293486"],
 "predicates":{
   "http://purl.org/dc/terms/identifier":"530369",
   "http://www.w3.org/2004/02/skos/core#inScheme":["http://id.worldcat.org/fast/ontology/1.0/#fast","http://id.worldcat.org/fast/ontology/1.0/#facet-Corporate"],
   "http://www.w3.org/1999/02/22-rdf-syntax-ns#type":"http://schema.org/Organization",
   "http://www.w3.org/2004/02/skos/core#prefLabel":"Cornell University",
   "http://schema.org/name":["Cornell University","Ithaca (N.Y.). Cornell University","Kornelʹskii universitet","Kʻang-nai-erh ta hsüeh"],
   "http://www.w3.org/2004/02/skos/core#altLabel":["Ithaca (N.Y.). Cornell University","Kornelʹskii universitet","Kʻang-nai-erh ta hsüeh"],
   "http://schema.org/sameAs":["http://id.loc.gov/authorities/names/n79021621","https://viaf.org/viaf/126293486"]}}

Validations come in two flavors...

• connection validation - PASS if a request gets back a specified minimum size result set from an authority; otherwise, FAIL.
• accuracy test - PASS if a specific result is returned by a specified position (e.g. uri is in the top 10 results); otherwise, FAIL.

The validations can be defined in a file with a matching file name in the scenarios directory. For example, direct access to the AgroVoc authority, access is configured in config/authorities/linked_data/agrovoc_direct.json and the validations are defined in config/authorities/linked_data/scenarios/agrovoc_direct_validation.yml

The UI for qa_server provides access to running connection validation and accuracy tests in the Check Status navigation menu item.

QA Server is based on the Questioning Authority gem. As such, it can be used to serve up controlled vocabularies defined in one of three ways.

1. locally defined controlled vocabularies
2. specifically supported external authorities (non-linked data)
3. configurable access to linked data authorities

This document addresses the use of QA Server app for access to linked data authorities. You can reference Questioning Authorities documentation for more information on the other uses.