membership-attribute-service/app/filters/CheckCacheHeadersFilter.scala

package filters

import org.apache.pekko.stream.Materializer
import controllers.Cached.suitableForCaching
import play.api.mvc._

import scala.concurrent.{ExecutionContext, Future}

class CheckCacheHeadersFilter(implicit val mat: Materializer, ex: ExecutionContext) extends Filter {

  def apply(nextFilter: RequestHeader => Future[Result])(requestHeader: RequestHeader): Future[Result] = {
    nextFilter(requestHeader).map { result =>
      if (requestHeader.method.toUpperCase != "OPTIONS" && suitableForCaching(result)) {
        val hasCacheControl = result.header.headers.contains("Cache-Control")
        assert(
          hasCacheControl,
          s"Cache-Control not set. Ensure controller response has Cache-Control header set for ${requestHeader.path}. Throwing exception... ",
        )
      }
      result
    }
  }
}