RFC 9110 / RESPONSES AND BOUNDARIES

Caches & revalidation

A cache can reuse a prior response when allowed. Stale entries can sometimes be validated without retransmitting content.

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DIAGRAM§ 3.8 ↗

RFC 9110 · § 3.8EXAMPLE

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Serve the validated response.

The cache applies RFC 9111 rules to update and reuse its stored response.

Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references

KEY POINT

Distinguish reuse policy from validation.

HTTP caching stores responses for future equivalent requests.
Method semantics and response status affect whether a response is cacheable.
RFC 9111 supplies the detailed freshness, storage, and reuse rules; RFC 9110 defines the associated semantics and conditional requests.

DETAILS

This chapter illustrates the interface with caching. It does not imply every GET is cacheable, or that a cache may reuse any stored response without checking policy.

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Diagrams simplify the RFC. Read the linked sections for complete requirements.

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