HDATA — Enable the use of version-aware resource URLs

Most of the changes requested in this section apply to 6.5 of the
hData specification.
FHIR will need to be able to access different versions of a resource.
To enable this most
effectively, the spec should support the following URL extensions on
SectionDocuments
for GET, PUT, and POST operations:

(resourceURL) = (baseURL)/(sectionPath)/(sectionDocument)
(versionAwareResourceURL) = (resource)/history/(version-id)

where (version-id) is any unique string. Also, a GET on the (resourceURL) should
return the representation of the resource in the HTTP body, a status
code of 200, and
a Content-Location header containing the (versionAwareResourceURL) of
the current
version of that resource.

If the resource was deleted with a DELETE, the service SHOULD return a
HTTP status
code 410, with no body. However it MAY return a 404 as alternative.

To enable safe updates, the following process MUST be used:

• The client reads obtains the representation of the current version
by performing a GET
on the (resourceURL). This contains the reference to (versionAwareResourceURL).
• The client makes the necessary changes to the state.
• The client MUST then PUT the updates representation to the
(resourceURL) and quote the versionAwareResourceURL in the Content-Location
header of the PUT operation.
• If the (versionAwareResourceURL) provided by the client is the
current version, the
server accepts the representation and persists the change, and returns a HTTP
response with
• a status code of 202 ok,
• a Content-Location header with the (versionAwareResourceURL) of the new

version, and
• the representation of the new version of the resource in the
• If the (versionAwareResourceURL) represents no longer the current version, the
server MUST return a HTTP response with status code 412, a Content-Location
header with the new (versionAwareResourceURL), and a representation of
the latest
version of the resource.

Added version-aware scheme to 6.5, edited 6.5.1 and 6.5.3 (formerly 6.5.2) to address concern