Is there a way to retroactively create time/node based UUID in PHP?

Question

Most time-based (type 1) UUIDs are created using the current time. I'm migrating a MySQL database to cassandra and would like to create timebased UUIDs for archived items. Can someone provide an example of how type-1 UUIDs are created using past time periods?

Answer 1

All uuids version 1 are a combination of node identifier (MAC address), timestamp and a random seed.

Yes its possible. The process is reversible.

From RFC4122 about the timestamp part of UUID version 1 (section 4.1.4):

"For UUID version 1, this is represented by Coordinated Universal Time (UTC) as a count of 100-nanosecond intervals since 00:00:00.00, 15 October 1582 (the date of Gregorian reform to the Christian calendar)."

Basic algorithm (section 4.2.1) for creating time base UUID (uuid version 1)