How to access specific data

How to find things in Fedora

The map between Drupal URIs and their corresponding Fedora URIs is stored in a service called Gemini. An Islandora “pseudo-field” can be enabled that will display the corresponding Fedora URI on the page of a node, taxonomy term, or media object. You can also query Gemini directly. Instructions for doing that are provided below.

For more information about the Gemini service, see the Gemini README.

How to look up a Fedora URI through Gemini

(nodes and taxonomy terms)

In Gemini, each entry is keyed on the UUID assigned by Drupal (the long one, not the node id). To get the UUID of a node, or taxonomy term in Drupal, you can look in the Devel tab or in the JSON representation, e.g.: http://localhost:8000/node/2?_format=json.

How to look up a Fedora URI through Gemini (files)

Files in Fedora have the file URI in Gemini, and can be queried based on the UUID (accessible from the Media’s json) or their URI.

select fedora_uri from Gemini where drupal_uri = 'http://localhost:8000/_flysystem/fedora/2019-05/639647.jpg';

How do I search for a object in the Solr

• Go to http://localhost:8983/solr/#/islandora/query
• Issue a Solr query.

Sample Triplestore queries

Go to http://localhost:8080/bigdata/#query Under namespaces (http://localhost:8080/bigdata/#namespaces), make sure islandora is selected.

Find all triples with given object as the subject

Formatting is important. Which letters are not important. They represent a variable you want back. You can also consider them to behave like willdcards *

  select ?a ?b where {               <--- First Line (no leading spaces)
      <drupal_url> ?a ?b                <--- 2nd Line
    }                                                  <--- Closing Line

Example:

Example want any triples where a and b can be anything but the first value must match <http://localhost:8000/media/8?_format=jsonld>

  select ?a ?b where {
      <http://localhost:8000/media/8?_format=jsonld> ?a ?b
    }

To get everything for an object (very useful). This query starts with a subject (<http://islandora-isle-dc-3-93-28-63.traefik.me?_format=jsonld>) with place holders for the predicates(a) and objects(b) and returning a list with the predicates(a) and objects(b) that start with specified subject.

select ?a ?b where { 
  <http://islandora-isle-dc-3-93-28-63.traefik.me/node/839> ?a ?b
}

Output for all triples that start with <http://islandora-isle-dc-3-93-28-63.traefik.me?_format=jsonld>

|  a  |  b  |
| ?a  | ?b |
...

Results

Get everything

This is a quick example that will get everything. This is the catch all.

select ?s ?o ?x {
  ?s ?o ?x
}

For more examples see Testing Notes