tools/src/main/scala/org/apache/predictionio/tools/dashboard/CorsSupport.scala

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.predictionio.tools.dashboard

// Reference from: https://gist.github.com/jeroenr/5261fa041d592f37cd80

import akka.http.scaladsl.model.HttpMethods._
import akka.http.scaladsl.model.{StatusCodes, HttpResponse}
import akka.http.scaladsl.model.headers._
import akka.http.scaladsl.server.Directives._
import akka.http.scaladsl.server.{Directive0, Route}
import com.typesafe.config.ConfigFactory

trait CorsSupport {

  // this directive adds access control headers to normal responses
  private def addAccessControlHeaders: Directive0 = {
    respondWithHeaders(
      `Access-Control-Allow-Origin`.forRange(HttpOriginRange.`*`),
      `Access-Control-Allow-Credentials`(true),
      `Access-Control-Allow-Headers`("Authorization", "Content-Type", "X-Requested-With")
    )
  }

  // this handles preflight OPTIONS requests.
  private def preflightRequestHandler: Route = options {
    complete(HttpResponse(StatusCodes.OK)
      .withHeaders(`Access-Control-Allow-Methods`(OPTIONS, POST, PUT, GET, DELETE)))
  }

  def corsHandler(r: Route): Route = addAccessControlHeaders {
    preflightRequestHandler ~ r
  }
}