headerValue
Traverses the list of request headers with the specified function and extracts the first value the function returns as
Some(value)
.
Signature
def headerValue[T](f: HttpHeader ⇒ Option[T]): Directive1[T]
Description
The headerValue
directive is a mixture of map
and find
on the list of request headers. The specified function
is called once for each header until the function returns Some(value)
. This value is extracted and presented to the
inner route. If the function throws an exception the request is rejected with a MalformedHeaderRejection
. If the
function returns None
for every header the request is rejected as “NotFound”.
This directive is the basis for building other request header related directives. See headerValuePF
for a nicer
syntactic alternative.
Example
def extractHostPort: HttpHeader => Option[Int] = {
case h: `Host`=> Some(h.port)
case x => None
}
val route =
headerValue(extractHostPort) { port =>
complete(s"The port was $port")
}
Get("/") ~> Host("example.com", 5043) ~> route ~> check {
responseAs[String] === "The port was 5043"
}
Get("/") ~> sealRoute(route) ~> check {
status === NotFound
responseAs[String] === "The requested resource could not be found."
}