Follow policy information without blind migration
04A sunset link can explain policy, timing or migration options. It does not redirect the client or authorize automatic identity changes.
The chosen policy covers /api/*, so a proposed move of /other/photos is not applied. This is an example safety decision, not an invented unconditional MUST.
Source for this drawing: RFC 8594 · Read RFC section 6 ↗
New to this? Start hereA quick picture + helpful background
A message needs an address.
Think of a packet as a small addressed envelope. Devices pass it onward; transport protocols decide what delivery promises an application gets.
Helpful first, if these ideas are unfamiliar
These pictures are analogies to help you learn. The linked RFC explains the actual rules.
Terms in this drawing
- Link relation sunset
- The relationship means retirement-policy information, not a replacement address.
- Authentic and accurate
- The policy comes from an appropriate source and correctly describes the intended resources and actions.
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
Check policy authenticity, accuracy and scope before acting on it.
- The sunset link relation identifies information about the context’s retirement policy. It can describe general policy, an upcoming sunset or possible migration; the linked format can target humans, machines or both.
- The link can be advertised before a Sunset timestamp appears. The RFC does not prescribe a policy document format, a migration algorithm or when a client should switch resources.
- Clients SHOULD be careful about acting on linked policy, SHOULD verify authenticity and accuracy, and SHOULD test that it applies only within the policy’s scope. Otherwise migration information could hijack unrelated resources.
- An expiration-like Sunset date can disclose timing or enable inference of another date, such as creation time under a known retention rule. Treat that disclosure like making the information available in the representation; this guide uses only fictional examples.
Fictional example Link: <https://docs.example/sunset>; rel="sunset"; type="text/html". HTML is this example’s chosen format, not a requirement. The depicted policy applies to /api/*; a proposal to move /other/photos is outside that scope and is refused in this example. Reading the link is not a redirect and does not prove the policy is authentic or accurate. No linked document is fetched by this demonstration.
Read the RFC section ↗