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| − | == Introduction == | + | [[Image:Higgins_logo_76Wx100H.jpg|right]] |
| − | This page describes and defines a Higgins [[ContextId]]. | + | == Version == |
| − | See also: [[Context Discovery]] and [[Context Discovery Components]].
| + | This page describes the concept of a [[ContextId]] as used in [[Context Data Model 2.0]]. |
| | | | |
| | == Definition == | | == Definition == |
| − | * A [[ContextId]] is a kind of [[Context Correlation]] that identifies an instance of a [[Context]]. | + | * An identifier of a [[Context]] |
| − | * A [[ContextId]] MUST have a single value | + | * A ''Context UDI'' as defined in [http://www.azigo.com/udi/udi-syntax.html UDI Syntax] |
| − | * The single value of a [[ContextId]] MUST be a [[ContextIdDatatype]]
| + | |
| | | | |
| − | == Details ==
| + | [[Category:Context Data Model 2.0]] |
| − | * The value of a [[ContextId]] must directly or indirectly (e.g. by resolution) provide sufficient information to identify a [[Context]]. See the ''Context Discovery with a ContextId'' heading below.
| + | |
| − | * Two different [[ContextId]]s may refer to the same [[Context]].
| + | |
| − | | + | |
| − | == ContextId and IdAS ==
| + | |
| − | * If two [[ContextId]]'s values are equal, they refer to the same underlying [[Context]], although not necessarily the same [[Context]] "container" instance returned by IdAS. This means that, as a requester of information, different [[Digital Identity|Digital Identities]] may see different subsets of the [[Context]] based on the authorization passed in during authentication.
| + | |
| − | * A given [[ContextId]] may be used against multiple [[Context Provider]]s to produce the same [[Context]] (although, as mentioned, different [[Context]] instances).
| + | |
| − | | + | |
| − | == Details ==
| + | |
| − | * The [[Identity Attribute Service (IdAS)]] can be used as a service to access a [[Context]] given a [[ContextId]]
| + | |
| − | | + | |
| − | Some [[ContextId]]s are not resolvable to a [[Context]] instance. Most [[Context]]s are not abstract. Using a network (or local) data access service their [[ContextId]]s are resolvable to data objects that are instantiated and managed by [[Context Provider]] plug-ins.
| + | |
| − | | + | |
| − | | + | |
| − | | + | |
| − | == Examples ==
| + | |
| − | | + | |
| − | === contextURI ===
| + | |
| − | | + | |
| − | ==== contextfileURI ====
| + | |
| − | | + | |
| − | file://system/config/openid.xrds
| + | |
| − | file://system/config/openid.xdi
| + | |
| − | file://system/config/ldap.xrds
| + | |
| − | file://system/config/ldap.xdi
| + | |
| − | | + | |
| − | ==== contexthttpURI ====
| + | |
| − | | + | |
| − | http://example.com
| + | |
| − | https://example.com
| + | |
| − | http://example.com
| + | |
| − | https://example.com
| + | |
| − | http://example.com/higgins/openid.xrds
| + | |
| − | https://example.com/higgins/openid.xdi
| + | |
| − | http://example.com/higgins/ldap.xrds
| + | |
| − | https://example.com/higgins/ldap.xdi
| + | |
| − | | + | |
| − | === ContextQXRI ===
| + | |
| − | | + | |
| − | ==== contextQXRI – XRI 2.0 Form ====
| + | |
| − | | + | |
| − | =drummond
| + | |
| − | =drummond/($context)
| + | |
| − | =drummond/($context)*($openid)
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| − | =drummond/($context)*($ldap)
| + | |
| − | =!F83.62B1.44F.2813
| + | |
| − | =!F83.62B1.44F.2813/($context)*($openid)
| + | |
| − | =!F83.62B1.44F.2813/($context)*($ldap)
| + | |
| − | =drummond*mom
| + | |
| − | =drummond*mom/($context)*($openid)
| + | |
| − | =drummond*mom/($context)*($ldap)
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| − | @example
| + | |
| − | @example/($context)
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| − | @example/($context)*($openid)
| + | |
| − | @example/($context)*($ldap)
| + | |
| − | @free*example
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| − | @free*example/($context)*($openid)
| + | |
| − | @free*example/($context)*($ldap)
| + | |
| − | | + | |
| − | ==== contextQXRI – Proposed XRI 3.0 Form ====
| + | |
| − | | + | |
| − | =drummond
| + | |
| − | =drummond/$context
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| − | =drummond/$context$openid
| + | |
| − | =drummond/$context$ldap
| + | |
| − | =!F83.62B1.44F.2813
| + | |
| − | =!F83.62B1.44F.2813/$context$openid
| + | |
| − | =!F83.62B1.44F.2813/$context$$ldap
| + | |
| − | =drummond*mom
| + | |
| − | =drummond*mom/$context$openid
| + | |
| − | =drummond*mom/$context$ldap
| + | |
| − | @example
| + | |
| − | @example/$context
| + | |
| − | @example/$context$openid
| + | |
| − | @example/$context$ldap
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| − | @free*example
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| − | @free*example/$context$openid
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| − | @free*example/$context$ldap
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| − | | + | |
| − | === contextHXRI ===
| + | |
| − | A contextHXRI is a ContextQXRI that uses an HXRI proxy resolver prefix. "xri.net" is a public HXRI proxy resolver operated by XDI.org. All others are examples.
| + | |
| − | | + | |
| − | ==== contextHXRI – XRI 2.0 Form ====
| + | |
| − | | + | |
| − | http://xri.net/=drummond
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| − | http://xri.net/=drummond/($context)
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| − | https://xri.net/=drummond/($context)*($openid)
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| − | https://xri.net/=drummond*mom/($context)*($openid)
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| − | http://xri.example.com/@example/($context)*($openid)
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| − | http://xri.example.com/@free*example/($context)*($openid)
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| − | https://xri.example.org/@1000.a1b2.c3d4.9999!1234/($context)*($ldap)
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| − | | + | |
| − | ==== contextHXRI – Proposed XRI 3.0 Form ====
| + | |
| − | | + | |
| − | http://xri.net/=drummond
| + | |
| − | http://xri.net/=drummond/$context
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| − | https://xri.net/=drummond/$context$openid
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| − | https://xri.net/=drummond*mom/$context$openid
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| − | http://xri.example.com/@example/$context$openid
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| − | http://xri.example.com/@example*free/$context$openid
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| − | https://xri.example.org/@1000.a1b2.c3d4.9999!1234/$context$ldap
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| − | | + | |
| − | == Context Discovery Rules ==
| + | |
| − | A key property of a [[ContextId]] is that it can be resolved into the metadata necessary open a [[Context]]. The complete process for doing this is described in [[Context Discovery]]. Following are the discovery rules that apply to each form of ContextId.
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| − | | + | |
| − | === contextURI Discovery ===
| + | |
| − | Since URIs do not offer the structured identifier features of XRIs, they must resolve directly to an XRDS or XDI document containing the Higgins context configuration metadata for a specific context type.
| + | |
| − | | + | |
| − | ==== contextfileURI ====
| + | |
| − | # Open the identified file.
| + | |
| − | # For an XRDS file, select the highest priority service endpoint that conforms to the [[Higgins XRDS Service Endpoint]] requirements.
| + | |
| − | # For an XDI X3 file, parse the Higgins context configuration metadata from the X3 document as described in [[Higgins XDI Context Reference]].
| + | |
| − | | + | |
| − | ==== contexthttpURI ====
| + | |
| − | # Resolve the URI to a discovery document as specified in Section 6 of [http://docs.oasis-open.org/xri/2.0/specs/cd02/xri-resolution-V2.0-cd-02.pdf XRI Resolution 2.0].
| + | |
| − | ## If the contexthttpURI ends in the context descriptor extension '''.xrds''' for an XRDS document, use the MIME type '''application/xrds+xml'''.
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| − | ## If the contexthttpURI ends in the context descriptor extension '''.xdi''' for an XDI document, use the MIME type '''text/x3'''.
| + | |
| − | ## If the contexthttpURI does not end in a context descriptor extension, use either or both of these MIME types as preferred in content negotiation with the server.
| + | |
| − | # If the MIME type of the discovery document is '''application/xrds+xml''', select the highest priority service endpoint that conforms to the [[Higgins XRDS Service Endpoint]] requirements.
| + | |
| − | # If the MIME type is '''text/x3''', parse the Higgins context configuration metadata from the X3 document as described in [[Higgins XDI Context Reference]].
| + | |
| − | | + | |
| − | === contextXRI Discovery ===
| + | |
| − | Since XRIs are abstract structured identifiers intended designed explicitly for resource discovery and description, they offer more flexiblity in the discovery process.
| + | |
| − | | + | |
| − | ==== Using XRDS ====
| + | |
| − | # Resolve the authority component of the XRI as specified in [http://docs.oasis-open.org/xri/2.0/specs/cd02/xri-resolution-V2.0-cd-02.pdf XRI Resolution 2.0]. Trusted resolution is RECOMMENDED.
| + | |
| − | # From this XRDS document, select the Higgins service endpoint as defined in Section 13 of [http://docs.oasis-open.org/xri/2.0/specs/cd02/xri-resolution-V2.0-cd-02.pdf XRI Resolution 2.0]. Note that this provides a number of ways for ContextXRI authors to control service endpoint selection. Using the path component of the XRI to match a [[Higgins XRDS Service Endpoint]] is RECOMMENDED.
| + | |
| − | # Parse the Higgins context metadata as defined in [[Higgins XRDS Service Endpoint]].
| + | |
| − | | + | |
| − | ==== Using XDI ====
| + | |
| − | # Resolution of the authority component of the XRI may use either XRDS resolution or XDI context discovery.
| + | |
| − | ## For XRDS resolution, follow the same steps as described above, except that in the final XRDS document, the highest priority SEP of type '''xri://$xdi''' MUST be selected, and an XDI X3 document MUST be requested from that service endpoint URI.
| + | |
| − | ## For XDI context discovery, resolve the authority component of the XRI as specified in the XDI Contexts section of [http://wiki.oasis-open.org/xdi/XdiRdfModel XDI RDF Model]] document.
| + | |
| − | # In both cases, from the final XDI document, parse the XDI context description as defined in [[Higgins XDI Context Reference]].
| + | |
| − | | + | |
| − | == Relationship to OpenID ==
| + | |
| − | Any OpenID 2.0 identifier as defined by [http://openid.net/specs/openid-authentication-2_0.html OpenID Authentication 2.0] may function as a Higgins [[ContextId]]. OpenID 2.0 supports both URLs and XRIs. All of the examples of contexthttpURI and contextXRI above are valid OpenID 2.0 identifiers.
| + | |
| − | | + | |
| − | The only caveat to keep in mind is that if an OpenID 2.0 URL is used as a Higgins [[ContextId]], the XRDS or XDI document to which it resolves must EITHER contain:
| + | |
| − | * Only one XRDS service endpoint or XDI context reference describing the target [[Context]], OR
| + | |
| − | * The consuming application must know how to select the XRDS service endpoint or XDI context reference it requires (i.e., it must know which Higgins [[Context Type]] it is seeking).
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| − | | + | |
| − | == Open Issues ==
| + | |
| − | # Should the contextId ABNF support IRI (Internationalized Resource Identifiers) and not just URIs? Note that the ABNF above uses IRI rules; this needs to be changed if only URIs will be supported.
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| − | | + | |
| − | == See Also ==
| + | |
| − | * [[EntityId]]
| + | |
| − | * [[LocalId]]
| + | |
| − | * [[Context Discovery]]
| + | |
| − | * [[Context Discovery Components]]
| + | |
| − | * [[Higgins XRDS Service Endpoint]]
| + | |
| − | * [[Higgins XDI Context Reference]]
| + | |
| − | * [[Concepts]]
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| − | | + | |
| − | == Links ==
| + | |
| − | * [http://eclipse.org/higgins Higgins Home]
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