servedIs

servedIs is a term used in theoretical discussions of distributed web architectures to describe a pattern for delivering information states from servers to clients in a stateless interaction. The name merges "served" with IS, standing for Information State, a versioned snapshot of a resource that includes its identity, version, and essential metadata.

Core idea and components: a server exposes information state objects for resources, and clients carry tokens that identify the current state they possess. Caches, proxies, and downstream services use these tokens to determine whether they hold the latest state, potentially avoiding full payload transfers while maintaining consistency. A state manifest or delta updates may accompany the token to indicate what has changed.

Mechanisms and semantics: state tokens function similarly to opaque identifiers or ETags but are designed to encode a broader notion of state, including versions and validity constraints. Implementations may pair tokens with versioned payloads, cryptographic hashes, or short change logs. The approach emphasizes deterministic cache invalidation and predictable refresh behavior across distributed components.

Applications and use cases: servedIs concepts can inform API design, content delivery strategies, and edge computing where precise control over when data is refreshed matters. It supports scenarios requiring low bandwidth for change notification, while still enabling clients to fetch full or partial updates on demand.

Limitations and considerations: the approach adds complexity in token management and state synchronization. Security risks exist if tokens reveal internal state or versioning details. It is a speculative concept and not part of formal standards, so interoperability would require explicit conventions.

See also: ETag, Cache-Control, REST, Content Delivery Network.