The ReST API allows you to poll for the status of certain operations by
performing a GET on various elements. Rather than re-downloading and re-parsing
the full status at each polling interval, your ReST client may use the
changes-since parameter to check for changes since a
previous request. The changes-since time is specified as
Unix time (the
number of seconds since January 1, 1970, 00:00:00 UTC, not counting leap seconds).
If nothing has changed since the changes-since time, a
304 (Not Modified) response will be returned. If data
has changed, only the items changed since the specified time will be returned in the
response. For example, performing a GET against
https://api.servers.rackspacecloud.com/v1.0/224532/servers?changes-since=1244012982
would list all servers that have changed since Wed, 03 Jun 2009 07:09:42 UTC.
