Header-Endpoint that only matches specific values, akin to path

It would be convenient to have a header-endpoint that matches iff a header is present with a particular value. This is useful in situations where one wants to provide different business logic depending on that value. An example of this is API-Versioning: Let’s assume that such an endpoint-factory would exist and header(x, y) matched iff header x was present with value y. Then one could solve this problem as follows:

val v1Endpoint: Endpoint[ResponseV1] =
  get("myEndpoint" :: header("X-API-VERSION", "1")) { /* ... */ }
val v2Endpoint: Endpoint[ResponseV2] =
  get("myEndpoint" :: header("X-API-VERSION", "2")) { /* ... */ }
val allVersions = v1Endpoint :+: v2Endpoint

[vkostyukov]

Perhaps headerExact("foo", "bar") could be a reasonable API to expose (that’s what warp uses)?

[d-s-d]

@sergeykolbasov That is the point, I think. Similar to the path, this endpoint can be used to dispatch a request. Maybe a different name would do: headerMatch, or headerDispatch. Or did I misunderstand your remark?