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The OpenURL Registry
The Registry names the formats, namespaces, identifiers, transports, and profiles used by the framework. Hosted at openurl.info by OCLC until 2022.
Z39.88-2004 is designed to be extensible through a Registry of named items rather than by amending the standard itself. The Registry holds the controlled vocabularies — the URIs by which an OpenURL refers to a metadata format, a namespace, an identifier scheme, a transport, a character encoding, or a Community Profile.
What the Registry contains
The Registry comprises six categories of registered item:
- Formats. URIs such as
info:ofi/fmt:kev:mtx:journalidentifying the metadata format used to describe an entity. - Namespaces. Identifier-namespace URIs, allowing identifiers from a namespace to be expressed as
info:<namespace>/<value>. - Identifiers. Specific registered URI prefixes for common identifier schemes.
- Transports. The three transport mechanisms: By-Value, By-Reference, Inline.
- Character encodings. Such as
info:ofi/enc:UTF-8. - Community Profiles. SAP1 and SAP2.
The four registered metadata formats
Four metadata formats were registered when the standard was published. Each is available in both KEV and XML serializations:
| Format | KEV identifier | XML identifier |
|---|---|---|
| Journal | info:ofi/fmt:kev:mtx:journal | info:ofi/fmt:xml:xsd:journal |
| Book | info:ofi/fmt:kev:mtx:book | info:ofi/fmt:xml:xsd:book |
| Dissertation | info:ofi/fmt:kev:mtx:dissertation | info:ofi/fmt:xml:xsd:dissertation |
| Patent | info:ofi/fmt:kev:mtx:patent | info:ofi/fmt:xml:xsd:patent |
No additional metadata formats were registered before the Registry was retired.
Hosting and status
The Registry was hosted at openurl.info by OCLC, who served as the Maintenance Agency for the standard. In 2022, OCLC announced that the Registry would be deprecated as a research prototype. openurl.info currently redirects to a static, read-only archived copy.
The deprecation does not invalidate any registered identifier. URIs such as info:ofi/fmt:kev:mtx:journal remain meaningful and are still used by every conformant implementation. What has ended is the registration of new items.
See Registry Deprecation for the full account.
The info: URI scheme
The Registry makes use of the info: URI scheme defined by RFC 4452. The OpenURL Framework reserves info:ofi/ as the namespace for its own registered items (ofi for "OpenURL Framework Initiative"). The same scheme is used for identifying entities — info:doi/, info:pmid/, info:arxiv/ — through additional registered namespaces. See Identifiers.