Available-Dictionary header

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The HTTP Available-Dictionary request header allows the browser to specify the best matching dictionary it has to allow the server to use {{glossary("Compression Dictionary Transport")}} for a resource request.

Clients can send an Available-Dictionary header when they support dcb or dcz encodings. The header is a colon-surrounded base-64 encoded SHA-256 {{glossary("Hash_function", "hash")}} of the dictionary contents.

See the Compression Dictionary Transport guide for more information.

Syntax

Available-Dictionary: :<base64-hash>:

Directives

• <base64-hash>
  • : A base-64 encoded SHA-256 {{glossary("Hash_function", "hash")}} of the dictionary contents.

Examples

Accept-Encoding: gzip, br, zstd, dcb, dcz
Available-Dictionary: :pZGm1Av0IEBKARczz7exkNYsZb8LzaMrV7J32a2fFG4=:

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Compression Dictionary Transport guide
• {{HTTPHeader("Use-As-Dictionary")}}
• {{HTTPHeader("Dictionary-ID")}}