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Comment: removed the Custom Namepsace registry information as it on the RDF best practises page now

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This optional feature allows an administrator to provide a list of custom namespace prefixes that will override the default prefix registry. The custom namespaces are loaded on start-up via a YAML file.  The namespaces can be modified while Fedora is running.  Changes may take a few minutes to take effect.

Below is a sample YAML namespace configuration file, custom_namespaces.yml.  Notice the "awesome" prefix definition at the bottom of the list. We will use this in the following example. NB: the custom file will override all default namespace prefixes.  In other words, the custom file becomes the definitive registry.  Any namespaces that are not prefixed will be returned as full URIs in the response. 

Code Block
premis:  http://www.loc.gov/premis/rdf/v1#
test:  info:fedora/test/
memento:  http://mementoweb.org/ns#
rdfs:  http://www.w3.org/2000/01/rdf-schema#
webac:  http://fedora.info/definitions/v4/webac#
acl:  http://www.w3.org/ns/auth/acl#
vcard:  http://www.w3.org/2006/vcard/ns#
xsi:  http://www.w3.org/2001/XMLSchema-instance
xmlns:  http://www.w3.org/2000/xmlns/
rdf:  http://www.w3.org/1999/02/22-rdf-syntax-ns#
fedora:  http://fedora.info/definitions/v4/repository#
xml:  http://www.w3.org/XML/1998/namespace
ebucore:  http://www.ebu.ch/metadata/ontologies/ebucore/ebucore#
ldp:  http://www.w3.org/ns/ldp#
dcterms:  http://purl.org/dc/terms/
iana:  http://www.iana.org/assignments/relation/
xs:  http://www.w3.org/2001/XMLSchema
fedoraconfig:  http://fedora.info/definitions/v4/config#
foaf:  http://xmlns.com/foaf/0.1/
dc:  http://purl.org/dc/elements/1.1/
awesome: http://example.com/awesome/

Fedora can activate the file by using the -Dfcrepo.namespace.registry system parameter, either on the command line or by adding it to the list of other params that provide paths to other configuration files:

Code Block
mvn jetty:run -Dfcrepo.namespace.registry=/my/fedora/path/custom_namespaces.yml

In order to demonstrate how this feature works,  try starting Fedora without  defining a custom namespace registry: 

Code Block
mvn jetty:run

Once Fedora is running,  run the following curl command

Code Block
echo "@prefix awesome: <http://example.com/awesome/> . <> awesome:stuff 'waffle' ." | curl -u fedoraAdmin:fedoraAdmin http://localhost:8080/rest/test  -X PUT -H "Content-Type: text/turtle" --data-binary "@-"

When you retrieve this resource,

Code Block
curl -i -u fedoraAdmin:fedoraAdmin http://localhost:8080/rest/test

notice the new predicate is expressed as the full URI.

Code Block
titleoutput
@prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix fedora:  <http://fedora.info/definitions/v4/repository#> .
@prefix ldp:  <http://www.w3.org/ns/ldp#> .

<http://localhost:8080/rest/test>
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        <http://example.com/awesome/test>  "waffle" ;
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Also notice there are built in prefixes for common namespaces.  Now restart Fedora with the custom namespaces yml enabled: 

Code Block
mvn jetty:run -Dfcrepo.namespace.registry=/my/fedora/path/custom_namespaces.yml

Retrieve the item and see how your custom namespace prefix is being used.

Code Block
curl -ufedoraAdmin:fedoraAdmin  http://localhost:8080/rest/test
@prefix awesome:  <http://example.com/awesome/> .
@prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix fedora:  <http://fedora.info/definitions/v4/repository#> .
@prefix ldp:  <http://www.w3.org/ns/ldp#> .

<http://localhost:8080/rest/test>
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        awesome:test           "waffle" ;
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More information on this feature can be found at the Best Practices - RDF Namespaces page.