Cache validation codes

text

304 Not Modified
412 Precondition Failed

Explanation

Conditional requests with ETag or date validators often center around `304` and `412`.

Learn the surrounding workflow

Compare similar commands or jump into common fixes when this command is part of a bigger troubleshooting path.

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Authentication versus authorization.

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Missing resource versus intentionally removed resource.

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Choose the right redirect semantics.

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Gateway and availability failures.

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Useful for scripts and health checks.

Show the redirect location without fully following it.