A web link relation type. Either a URI or a registered name.

Create a link relation type from a URI.

Try to parse a string into a URI, returning a link relation if successful.

Try to match a given link relation name against the registered names. Return the matching link relation if successful.

Try to parse the given string as a link relation, either as a registered name or as a URI. If both fail, return Nothing.

Check whether a link relation is represented by a URI, i.e. is not a link relation registered name.

Check whether a link relation is represented by a registered name, i.e. is not a URI.

Get the official registered name of a link relation (if it's a name) or its URI string (if it's a URI).

Refers to a resource that is the subject of the link's context.

Reference: RFC 6903, section 2

Refers to a substitute for this context

Reference: http://www.w3.org/TR/html5/links.html#link-type-alternate

Refers to an appendix.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

Refers to a collection of records, documents, or other materials of historical interest.

Reference: http://www.w3.org/TR/2011/WD-html5-20110113/links.html#rel-archives

Refers to the context's author.

Reference: http://www.w3.org/TR/html5/links.html#link-type-author

Gives a permanent link to use for bookmarking purposes.

Reference: http://www.w3.org/TR/html5/links.html#link-type-bookmark

Designates the preferred version of a resource (the IRI and its contents).

Reference: RFC 6596

Refers to a chapter in a collection of resources.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

The target IRI points to a resource which represents the collection resource for the context IRI.

Reference: RFC 6573

Refers to a table of contents.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

Refers to a copyright statement that applies to the link's context.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

The target IRI points to a resource where a submission form can be obtained.

Reference: RFC 6861

Refers to a resource containing the most recent item(s) in a collection of resources.

Reference: RFC 5005

The target IRI points to a resource from which this material was derived.

Reference: draft-hoffman-xml2rfc

Refers to a resource providing information about the link's context.

Reference: http://www.w3.org/TR/powder-dr/#assoc-linking

The relationship A 'describes' B asserts that resource A provides a description of resource B. There are no constraints on the format or representation of either A or B, neither are there any further constraints on either resource.

Reference: RFC 6892

Note: This link relation type is the inverse of the 'describedby' relation type. While 'describedby' establishes a relation from the described resource back to the resource that describes it, 'describes' established a relation from the describing resource to the resource it describes. If B is 'describedby' A, then A 'describes' B.

Refers to a list of patent disclosures made with respect to material for which 'disclosure' relation is specified.

Reference: RFC 6579

Refers to a resource whose available representations are byte-for-byte identical with the corresponding representations of the context IRI.

Reference: RFC 6249

Note: This relation is for static resources. That is, an HTTP GET request on any duplicate will return the same representation. It does not make sense for dynamic or POSTable resources and should not be used for them.

Refers to a resource that can be used to edit the link's context.

Reference: RFC 5023

The target IRI points to a resource where a submission form for editing associated resource can be obtained.

Reference: RFC 6861

Refers to a resource that can be used to edit media associated with the link's context.

Reference: RFC 5023

Identifies a related resource that is potentially large and might require special handling.

Reference: RFC 4287

An IRI that refers to the furthest preceding resource in a series of resources.

Reference: RFC 5988

Note: This relation type registration did not indicate a reference. Originally requested by Mark Nottingham in December 2004.

Refers to a glossary of terms.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

Refers to context-sensitive help.

Reference: http://www.w3.org/TR/html5/links.html#link-type-help

Refers to a resource hosted by the server indicated by the link context.

Reference: RFC 6690

Note: This relation is used in CoRE where links are retrieved as a "/.well-known/core" resource representation, and is the default relation type in the CoRE Link Format.

Refers to a hub that enables registration for notification of updates to the context.

Reference: http://pubsubhubbub.googlecode.com

Note: This relation type was requested by Brett Slatkin.

Refers to an icon representing the link's context.

Reference: http://www.w3.org/TR/html5/links.html#link-type-icon

Refers to an index.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

The target IRI points to a resource that is a member of the collection represented by the context IRI.

Reference: RFC 6573

An IRI that refers to the furthest following resource in a series of resources.

Reference: RFC 5988

Note: This relation type registration did not indicate a reference. Originally requested by Mark Nottingham in December 2004.

Points to a resource containing the latest (e.g., current) version of the context.

Reference: RFC 5829

Refers to a license associated with this context.

Reference: RFC 4946

Note: For implications of use in HTML, see: http://www.w3.org/TR/html5/links.html#link-type-license

Refers to further information about the link's context, expressed as a LRDD ("Link-based Resource Descriptor Document") resource. See RFC 6415 for information about processing this relation type in host-meta documents. When used elsewhere, it refers to additional links and other metadata. Multiple instances indicate additional LRDD resources. LRDD resources MUST have an "application/xrd+xml" representation, and MAY have others.

Reference: RFC 6415

The Target IRI points to a Memento, a fixed resource that will not change state anymore.

Reference: RFC 7089

Note: A Memento for an Original Resource is a resource that encapsulates a prior state of the Original Resource.

Refers to a resource that can be used to monitor changes in an HTTP resource.

Reference: RFC 5989

Refers to a resource that can be used to monitor changes in a specified group of HTTP resources.

Reference: RFC 5989

Indicates that the link's context is a part of a series, and that the next in the series is the link target.

Reference: http://www.w3.org/TR/html5/links.html#link-type-next

Refers to the immediately following archive resource.

Reference: RFC 5005

Indicates that the context’s original author or publisher does not endorse the link target.

Reference: http://www.w3.org/TR/html5/links.html#link-type-nofollow

Indicates that no referrer information is to be leaked when following the link.

Reference: http://www.w3.org/TR/html5/links.html#link-type-noreferrer

The Target IRI points to an Original Resource.

Reference: RFC 7089

Note: An Original Resource is a resource that exists or used to exist, and for which access to one of its prior states may be required.

Indicates a resource where payment is accepted.

Reference: RFC 5988

Note: This relation type registration did not indicate a reference. Requested by Joshua Kinberg and Robert Sayre. It is meant as a general way to facilitate acts of payment, and thus this specification makes no assumptions on the type of payment or transaction protocol. Examples may include a web page where donations are accepted or where goods and services are available for purchase. rel="payment" is not intended to initiate an automated transaction. In Atom documents, a link element with a rel="payment" attribute may exist at the feed/channel level and/or the entry/item level. For example, a rel="payment" link at the feed/channel level may point to a "tip jar" URI, whereas an entry/ item containing a book review may include a rel="payment" link that points to the location where the book may be purchased through an online retailer.

Points to a resource containing the predecessor version in the version history.

Reference: RFC 5829

Indicates that the link target should be preemptively cached.

Reference: http://www.w3.org/TR/html5/links.html#link-type-prefetch

Indicates that the link's context is a part of a series, and that the previous in the series is the link target.

Reference: http://www.w3.org/TR/html5/links.html#link-type-prev

Refers to a resource that provides a preview of the link's context.

Reference: RFC 6903, section 3

Refers to the previous resource in an ordered series of resources. Synonym for "prev".

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

Refers to the immediately preceding archive resource.

Reference: RFC 5005

Refers to a privacy policy associated with the link's context.

Reference: RFC 6903, section 4

Identifying that a resource representation conforms to a certain profile, without affecting the non-profile semantics of the resource representation.

Reference: RFC 6906

Note: Profile URIs are primarily intended to be used as identifiers, and thus clients SHOULD NOT indiscriminately access profile URIs.

Identifies a related resource.

Reference: RFC 4287

Identifies a resource that is a reply to the context of the link.

Reference: RFC 4685

Refers to a resource that can be used to search through the link's context and related resources.

Reference: http://www.opensearch.org/Specifications/OpenSearch/1.1

Refers to a section in a collection of resources.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

Conveys an identifier for the link's context.

Reference: RFC 4287

Indicates a URI that can be used to retrieve a service document.

Reference: RFC 5023

Note: When used in an Atom document, this relation type specifies Atom Publishing Protocol service documents by default. Requested by James Snell.

Refers to the first resource in a collection of resources.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

Refers to a stylesheet.

Reference: http://www.w3.org/TR/html5/links.html#link-type-stylesheet

Refers to a resource serving as a subsection in a collection of resources.

Reference: http://www.w3.org/TR/1999/REC-html401-19991224

Points to a resource containing the successor version in the version history.

Reference: RFC 5829

Gives a tag (identified by the given address) that applies to the current document.

Reference: http://www.w3.org/TR/html5/links.html#link-type-tag

Refers to the terms of service associated with the link's context.

Reference: RFC 6903, section 5

The Target IRI points to a TimeGate for an Original Resource.

Reference: RFC 7089

Note: A TimeGate for an Original Resource is a resource that is capable of datetime negotiation to support access to prior states of the Original Resource.

The Target IRI points to a TimeMap for an Original Resource.

Reference: RFC 7089

Note: A TimeMap for an Original Resource is a resource from which a list of URIs of Mementos of the Original Resource is available.

Refers to a resource identifying the abstract semantic type of which the link's context is considered to be an instance.

Reference: RFC 6903, section 6

Refers to a parent document in a hierarchy of documents.

Reference: RFC 5988

Note: This relation type registration did not indicate a reference. Requested by Noah Slater.

Points to a resource containing the version history for the context.

Reference: RFC 5829

Identifies a resource that is the source of the information in the link's context.

Reference: RFC 4287

Points to a working copy for this resource.

Reference: RFC 5829

Points to the versioned resource from which this working copy was obtained.

Reference: RFC 5829