accept.language_lookup

STRINGaccept.language_lookupSTRINGrequested_languagesSTRINGdefaultSTRINGaccept_header

Available in all 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.

Example

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

Try it out

accept.language_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

We welcome comments that add use cases, ideas, tips, and caveats. All comments will be moderated before publication. To post support questions, visit our support center and we'll find you the help you need.