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Host and Scheme Directives

Host directives provide filtering and extraction based on the request's Host header. Scheme directives operate on the URI scheme (e.g., http or https).

Host Directives​

extractHost​

Extracts the hostname from the request's Host header as a String.

val route: Route = extractHost { hostname =>
  complete(s"Host: $hostname")
}

host (name matching)​

Rejects the request if the hostname does not match any of the given names.

val route: Route = host("example.com", "www.example.com") {
  complete("Matched host")
}

host (predicate)​

Rejects the request if the predicate returns false for the hostname.

val route: Route = host(_.endsWith(".example.com")) {
  complete("Subdomain of example.com")
}

host (regex)​

Matches the hostname against a regular expression. If the regex contains no capturing group, the matched prefix is extracted. If it contains exactly one capturing group, the captured string is extracted. More than one capturing group throws an IllegalArgumentException.

import scala.util.matching.Regex

val route: Route = host("""(\w+)\.example\.com""".r) { subdomain =>
  complete(s"Subdomain: $subdomain")
}

Scheme Directives​

extractScheme​

Extracts the URI scheme from the request as a String.

val route: Route = extractScheme { scheme =>
  complete(s"Scheme: $scheme")
}

scheme​

Rejects the request if the URI scheme does not match the given name. Rejected requests receive a SchemeRejection.

val route: Route = scheme("https") {
  complete("Secure connection")
}