class SecondaryKeyCalculator extends AnyRef

This class produces secondary keys for a response from an origin server that contains a Vary header.

The cache must store the response with the requested header from the original request, so that subsequent requests match. This is a little confusing, so an example follows:

A request comes in with:

GET /some/path HTTP/1.1
Host: example.com
Accept-Encoding: gzip

The response comes back with a Vary header on the Accept-Encoding:

HTTP/1.1 200 OK
Vary: Accept-Encoding
Content-Encoding: gzip
Content-Type: application/json
Content-Length: 230
Cache-Control: max-age=10000000

The cache has to look at the Vary header, see that "Accept-Encoding" is a header on the request, and then store "Accept-Encoding: gzip" as a secondary key on the cache entry.

The implication is that the primary key entry of "GET http://example.com/some/path" is insufficient, and in order to get that specific response from cache, any subsequent requests should have a "Accept-Encoding: gzip" header in the same way.

Source
SecondaryKeyCalculator.scala
See also

https://tools.ietf.org/html/rfc7234#section-4.1

https://tools.ietf.org/html/rfc7231#section-7.1.4

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Instance Constructors

  1. new SecondaryKeyCalculator()

Value Members

  1. def calculate(request: CacheRequest, responseHeaders: Map[HeaderName, Seq[String]]): Option[Map[HeaderName, Seq[String]]]

    Finds the selecting header fields, based off the response's Vary header and the original request.

    Finds the selecting header fields, based off the response's Vary header and the original request.

    request

    the original request

    responseHeaders

    the origin response

    returns

    the selecting header fields, or None if there are no keys.