Available in all subroutines.

Selects the best match from a string in the format of an Accept-Charset header's value in the listed character sets using the algorithm described in Section 5.3.3 of RFC 7231.

This function takes the following parameters:

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


set bereq.http.Accept-Charset =
accept.charset_lookup("iso-8859-5:iso-8859-2", "utf-8",

Try it out

accept.charset_lookup is used in the following solution recipes, which show real world use cases. Click RUN to provision a Fastly service, execute the code on Fastly, and see how the function behaves.

Normalize requests

Improve cache performance by normalizing requests. Filter and reorder query params, convert to lowercase, filter headers, and more.

User contributed notes

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