Difference between revisions of "ContextId"

Revision as of 00:13, 9 December 2006

A ContextRef is a URI that identifies a Context.

• ContextRefs are used by the Identity Attribute Service (IdAS) and by Context Providers
• ContextRefs either directly or indirectly (e.g. by conventions, lookups, etc.) provide sufficient information to identify a Context
• A given ContextRef may be used against multiple Context Providers to produce the same Context (although 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

1. http://www.fabrikam123.example/4f544/ldap347/HR/employees --an LDAP employee directory
2. proprietary-scheme-a://contactlist -- user's contact list stored as tab-delimited file
3. xri://foo*bar/baz

Open issues

• Since providers are ultimately 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?