Available inall subroutines.

Selects the best match from a string in the format of an Accept-Language header's value in the listed languages using the algorithm described in RFC 4647, Section 3.4.

This function takes the following parameters:

  1. a colon-separated list of languages available for the resource,
  2. a fallback return value,
  3. a string representing an Accept-Language header's value.

This function conforms to RFC 4647.


set bereq.http.Accept-Language =
accept.language_lookup("en:de:fr:nl", "en",

Try it out

accept.language_lookup is used in the following code examples. Examples apply VCL to real-world use cases and can be deployed as they are, or adapted for your own service. See the full list of code examples for more inspiration.

Click RUN on a sample below to provision a Fastly service, execute the code on Fastly, and see how the function behaves.

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