Revalidate with 304
03A conditional request asks the origin whether a stored representation can still be used.
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAM§ 4.3 ↗
RFC 9111 · § 4.3EXAMPLE
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03
Update the stored metadata.
The cache selects the matching entry, updates it under §4.3.4, and serves its saved content.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
Read the updated RFC section ↗
An unchanged representation can reuse its stored content.
- Validation can send If-None-Match with stored entity tags, or an appropriate Last-Modified condition.
- A 304 response has no representation content; it identifies stored responses that can be freshened under the matching rules.
- Apply the 304 metadata to the identified stored responses before reusing their content. A changed representation can instead produce a new full response.
A 304 is not an empty replacement for the saved body. If a cache has no suitable stored response, it cannot invent the missing representation.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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