From 4d1197099ce4e721c18bf4cacbb2e1980e4210b5 Mon Sep 17 00:00:00 2001
From: Jakob Odersky <jakob@driver.xyz>
Date: Wed, 12 Sep 2018 16:40:57 -0700
Subject: Move REST functionality to separate project

---
 .../scala/xyz/driver/core/rest/DriverRoute.scala   | 122 +++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 core-rest/src/main/scala/xyz/driver/core/rest/DriverRoute.scala

(limited to 'core-rest/src/main/scala/xyz/driver/core/rest/DriverRoute.scala')

diff --git a/core-rest/src/main/scala/xyz/driver/core/rest/DriverRoute.scala b/core-rest/src/main/scala/xyz/driver/core/rest/DriverRoute.scala
new file mode 100644
index 0000000..911e306
--- /dev/null
+++ b/core-rest/src/main/scala/xyz/driver/core/rest/DriverRoute.scala
@@ -0,0 +1,122 @@
+package xyz.driver.core.rest
+
+import java.sql.SQLException
+
+import akka.http.scaladsl.model.headers.CacheDirectives.`no-cache`
+import akka.http.scaladsl.model.headers._
+import akka.http.scaladsl.model.{StatusCodes, _}
+import akka.http.scaladsl.server.Directives._
+import akka.http.scaladsl.server._
+import com.typesafe.scalalogging.Logger
+import org.slf4j.MDC
+import xyz.driver.core.rest
+import xyz.driver.core.rest.errors._
+
+import scala.compat.Platform.ConcurrentModificationException
+
+trait DriverRoute {
+  def log: Logger
+
+  def route: Route
+
+  def routeWithDefaults: Route = {
+    (defaultResponseHeaders & handleExceptions(ExceptionHandler(exceptionHandler))) {
+      route
+    }
+  }
+
+  protected def defaultResponseHeaders: Directive0 = {
+    extractRequest flatMap { request =>
+      // Needs to happen before any request processing, so all the log messages
+      // associated with processing of this request are having this `trackingId`
+      val trackingId    = rest.extractTrackingId(request)
+      val tracingHeader = RawHeader(ContextHeaders.TrackingIdHeader, trackingId)
+      MDC.put("trackingId", trackingId)
+
+      respondWithHeaders(tracingHeader +: DriverRoute.DefaultHeaders: _*)
+    }
+  }
+
+  /**
+    * Override me for custom exception handling
+    *
+    * @return Exception handling route for exception type
+    */
+  protected def exceptionHandler: PartialFunction[Throwable, Route] = {
+    case serviceException: ServiceException =>
+      serviceExceptionHandler(serviceException)
+
+    case is: IllegalStateException =>
+      ctx =>
+        log.warn(s"Request is not allowed to ${ctx.request.method} ${ctx.request.uri}", is)
+        errorResponse(StatusCodes.BadRequest, message = is.getMessage, is)(ctx)
+
+    case cm: ConcurrentModificationException =>
+      ctx =>
+        log.warn(s"Concurrent modification of the resource ${ctx.request.method} ${ctx.request.uri}", cm)
+        errorResponse(StatusCodes.Conflict, "Resource was changed concurrently, try requesting a newer version", cm)(
+          ctx)
+
+    case se: SQLException =>
+      ctx =>
+        log.warn(s"Database exception for the resource ${ctx.request.method} ${ctx.request.uri}", se)
+        errorResponse(StatusCodes.InternalServerError, "Data access error", se)(ctx)
+
+    case t: Exception =>
+      ctx =>
+        log.warn(s"Request to ${ctx.request.method} ${ctx.request.uri} could not be handled normally", t)
+        errorResponse(StatusCodes.InternalServerError, t.getMessage, t)(ctx)
+  }
+
+  protected def serviceExceptionHandler(serviceException: ServiceException): Route = {
+    val statusCode = serviceException match {
+      case e: InvalidInputException =>
+        log.info("Invalid client input error", e)
+        StatusCodes.BadRequest
+      case e: InvalidActionException =>
+        log.info("Invalid client action error", e)
+        StatusCodes.Forbidden
+      case e: UnauthorizedException =>
+        log.info("Unauthorized user error", e)
+        StatusCodes.Unauthorized
+      case e: ResourceNotFoundException =>
+        log.info("Resource not found error", e)
+        StatusCodes.NotFound
+      case e: ExternalServiceException =>
+        log.error("Error while calling another service", e)
+        StatusCodes.InternalServerError
+      case e: ExternalServiceTimeoutException =>
+        log.error("Service timeout error", e)
+        StatusCodes.GatewayTimeout
+      case e: DatabaseException =>
+        log.error("Database error", e)
+        StatusCodes.InternalServerError
+    }
+
+    { (ctx: RequestContext) =>
+      import xyz.driver.core.json.serviceExceptionFormat
+      val entity =
+        HttpEntity(ContentTypes.`application/json`, serviceExceptionFormat.write(serviceException).toString())
+      errorResponse(statusCode, entity, serviceException)(ctx)
+    }
+  }
+
+  protected def errorResponse[T <: Exception](statusCode: StatusCode, message: String, exception: T): Route =
+    errorResponse(statusCode, HttpEntity(message), exception)
+
+  protected def errorResponse[T <: Exception](statusCode: StatusCode, entity: ResponseEntity, exception: T): Route = {
+    complete(HttpResponse(statusCode, entity = entity))
+  }
+
+}
+
+object DriverRoute {
+  val DefaultHeaders: List[HttpHeader] = List(
+    // This header will eliminate the risk of envoy trying to reuse a connection
+    // that already timed out on the server side by completely rejecting keep-alive
+    Connection("close"),
+    // These 2 headers are the simplest way to prevent IE from caching GET requests
+    RawHeader("Pragma", "no-cache"),
+    `Cache-Control`(List(`no-cache`(Nil)))
+  )
+}
-- 
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