alwaysCache

Signature

def alwaysCache[K](cache: Cache[K, RouteResult], keyer: PartialFunction[RequestContext, K]): Directive0

Description

Like cache but disregards a Cache-Control request header.

Example

Scala
import akka.http.scaladsl.server.directives.CachingDirectives._
import akka.http.scaladsl.server.RequestContext
import akka.http.scaladsl.model.Uri
import akka.http.scaladsl.model.headers.{ Authorization, `Cache-Control` }
import akka.http.scaladsl.model.headers.CacheDirectives.`no-cache`

//Example keyer for non-authenticated GET requests
val simpleKeyer: PartialFunction[RequestContext, Uri] = {
  val isGet: RequestContext => Boolean = _.request.method == GET
  val isAuthorized: RequestContext => Boolean =
    _.request.headers.exists(_.is(Authorization.lowercaseName))
  val result: PartialFunction[RequestContext, Uri] = {
    case r: RequestContext if isGet(r) && !isAuthorized(r) => r.request.uri
  }
  result
}

// Created outside the route to allow using
// the same cache across multiple calls
val myCache = routeCache[Uri]

var i = 0
val route =
  path("cached") {
    alwaysCache(myCache, simpleKeyer) {
      complete {
        i += 1
        i.toString
      }
    }
  }

Get("/cached") ~> route ~> check {
  responseAs[String] shouldEqual "1"
}
// now cached
Get("/cached") ~> route ~> check {
  responseAs[String] shouldEqual "1"
}
Get("/cached") ~> `Cache-Control`(`no-cache`) ~> route ~> check {
  responseAs[String] shouldEqual "1"
}
Java
final CachingSettings cachingSettings = CachingSettings.create(system());
// Example keyer for non-authenticated GET requests
final JavaPartialFunction<RequestContext, Uri> simpleKeyer = new JavaPartialFunction<RequestContext, Uri>() {
  public Uri apply(RequestContext in, boolean isCheck) {
    final HttpRequest request = in.getRequest();
    final boolean isGet = request.method() == HttpMethods.GET;
    final boolean isAuthorized = request.getHeader(Authorization.class).isPresent();

    if (isGet && !isAuthorized)
      return request.getUri();
    else
      throw noMatch();
  }
};

// Created outside the route to allow using
// the same cache across multiple calls
final Cache<Uri, RouteResult> myCache = routeCache(cachingSettings);

final AtomicInteger count = new AtomicInteger(0);
final Route route = path("cached", () ->
    alwaysCache(myCache, simpleKeyer, () ->
    extractUri(uri ->
      complete(String.format("Request for %s @ count %d", uri, count.incrementAndGet()))
    )
  )
);

// tests:
testRoute(route)
  .run(HttpRequest.GET("/cached"))
  .assertEntity("Request for http://example.com/cached @ count 1");

// now cached
testRoute(route)
  .run(HttpRequest.GET("/cached"))
  .assertEntity("Request for http://example.com/cached @ count 1");

final CacheControl noCache = CacheControl.create(CacheDirectives.NO_CACHE);
testRoute(route)
  .run(HttpRequest.GET("/cached").addHeader(noCache))
  .assertEntity("Request for http://example.com/cached @ count 1");
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