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ContextId
Revision as of 00:22, 9 December 2006 by Unnamed Poltroon (Talk)
- A ContextRef is a URI that identifies a Context.
- ContextRefs either directly or indirectly (e.g. by conventions, lookups, etc.) provide sufficient information to identify a Context
- Two different ContextRefs may refer to the same Context
- If two ContextRefs are equal, they refer to the same Context dataset, although not necessarily the same Context "container" instance
- ContextRefs are used by the Identity Attribute Service (IdAS) and by Context Providers
- A given ContextRef may be used against multiple Context Providers to produce the same Context (although, as mentioned, different IContext instances).
- ContextRefs MAY be XRIs
- ContextRefs MUST be subdivideable by "/" (e.g. to allow constructing through the following possible kind of concatenation: <contextRef-root>/<schemaType>/<object-identifier>
Examples
- http://www.fabrikam123.example/4f544/ldap347/HR/employees --an LDAP employee directory
- proprietary-scheme-a://contactlist -- user's contact list stored as tab-delimited file
- xri://foo*bar/baz
Open issues
- Context providers are in some cases (i.e. cases where the provider is creating a new Context and associated ContextRef) the generators/assigners of new ContextRefs. Should we allow them to assign their own schemes if they use proprietary technology (as in "proprietary-scheme-a" in #2 above)?
- Do we assume all URIs that use the HTTP scheme are resolvable? (URLs)
- Beyond resolvable, should we require as Tony has suggested that all HTTP-scheme URIs are also WS-Addressing endpoint references? (This would solve the problem of how a provider could get the policy and other metadata to help it try to open and access the context data)
- Do we need a method in IdAS to test that two given ContextRefs actually resolve to the same Context?