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Q&A
Q&AIdempotence describes the intended effect, not identical response bytes or status codes. POST needs an explicit deduplication contract before ambiguous retries are safe.
Idempotence describes the intended effect, not identical response bytes or status codes. POST needs an explicit deduplication contract before ambiguous retries are safe.
http
5 minDesign a predictable request and response contract by distinguishing resources, representations, safe methods, and retryable operations.
http
8 minUse validators, Content-Range, and 416 handling to make partial downloads coherent.
http
6 minUse strong validators and atomic preconditions to prevent lost updates without confusing them with retry identity.
http
5 minKeep list traversal stable, validate cached representations, and bound retry work when networks fail at ambiguous points.
Q&A
Q&ANo; it identifies an expected version, not a logical operation.
A committed first attempt advances the validator, so a repeat with the old validator may fail with 412. Use a separate scoped idempotency contract when retries must recover the original result.
Q&A
Q&AThe representation may have changed since the saved prefix was downloaded.
Use a validator such as a strong ETag with If-Range, validate the 206 Content-Range before append, and verify final integrity separately. An ETag is not necessarily a cryptographic digest.
Q&A
Q&AA 304 validates a previously cached representation and does not provide a replacement body. Cache policy and authorization still control whether reuse is appropriate.
A 304 validates a previously cached representation and does not provide a replacement body. Cache policy and authorization still control whether reuse is appropriate.