fix: return 400 for Elasticsearch query parse errors instead of 500

src/main/scala/dpla/api/v2/registry/SearchRegistryBehavior.scala

@@ -40,6 +40,8 @@ final case class RegisterRandom(
 
 trait SearchRegistryBehavior {
 
+  private val QueryParseErrorMessage = "The q parameter contains invalid search syntax."
+
   def spawnSearchActor(context: ActorContext[SearchRegistryCommand]):
     ActorRef[SearchCommand]
 
@@ -183,6 +185,10 @@ trait SearchRegistryBehavior {
           searchResponse = Some(NotFoundFailure)
           possibleSessionResolution
 
+        case SearchQueryParseFailure =>
+          searchResponse = Some(ValidationFailure(QueryParseErrorMessage))
+          possibleSessionResolution
+
         case SearchFailure =>
           searchResponse = Some(InternalFailure)
           possibleSessionResolution
@@ -298,6 +304,10 @@ trait SearchRegistryBehavior {
           fetchResponse = Some(NotFoundFailure)
           possibleSessionResolution
 
+        case SearchQueryParseFailure =>
+          fetchResponse = Some(InternalFailure)
+          possibleSessionResolution
+
         case SearchFailure =>
           fetchResponse = Some(InternalFailure)
           possibleSessionResolution
@@ -383,6 +393,10 @@ trait SearchRegistryBehavior {
           randomResponse = Some(ValidationFailure(message))
           possibleSessionResolution
 
+        case SearchQueryParseFailure =>
+          randomResponse = Some(ValidationFailure(QueryParseErrorMessage))
+          possibleSessionResolution
+
         case SearchFailure =>
           randomResponse = Some(InternalFailure)
           possibleSessionResolution

src/main/scala/dpla/api/v2/search/ElasticSearchClient.scala

@@ -228,8 +228,11 @@ object ElasticSearchClient {
           nextPhase ! SearchQueryResponse(params, body, replyTo)
           Behaviors.stopped
 
-        case ElasticSearchHttpError(_) =>
-          replyTo ! SearchFailure
+        case ElasticSearchHttpError(statusCode) =>
+          if (statusCode.intValue == 400)
+            replyTo ! SearchQueryParseFailure
+          else
+            replyTo ! SearchFailure
           Behaviors.stopped
 
         case ElasticSearchResponseFailure =>
@@ -385,8 +388,11 @@ object ElasticSearchClient {
           nextPhase ! RandomQueryResponse(params, body, replyTo)
           Behaviors.stopped
 
-        case ElasticSearchHttpError(_) =>
-          replyTo ! SearchFailure
+        case ElasticSearchHttpError(statusCode) =>
+          if (statusCode.intValue == 400)
+            replyTo ! SearchQueryParseFailure
+          else
+            replyTo ! SearchFailure
           Behaviors.stopped
 
         case ElasticSearchResponseFailure =>

src/main/scala/dpla/api/v2/search/SearchProtocol.scala

@@ -52,6 +52,7 @@ object SearchProtocol {
   final case object FetchNotFound extends SearchResponse
   final case object SearchNotFound extends SearchResponse
   final case object SearchFailure extends SearchResponse
+  final case object SearchQueryParseFailure extends SearchResponse
 
   /**
    * Internal command protocol.

src/test/scala/dpla/api/v2/endToEnd/InvalidParamsTest.scala

@@ -8,7 +8,8 @@ import akka.http.scaladsl.testkit.ScalatestRouteTest
 import dpla.api.Routes
 import dpla.api.helpers.ActorHelper
 import dpla.api.helpers.Utils.fakeApiKey
-import dpla.api.v2.registry.{MockSmrRegistry, SmrRegistryCommand}
+import dpla.api.v2.registry.{MockItemRegistry, MockSmrRegistry, SmrRegistryCommand}
+import dpla.api.v2.search.{MockEsClientQueryParseError, MockItemSearch}
 import dpla.api.v2.smr.MockSmrRequestHandler
 import dpla.api.v2.smr.SmrProtocol.SmrCommand
 import org.scalatest.matchers.should.Matchers
@@ -35,6 +36,17 @@ class InvalidParamsTest extends AnyWordSpec with Matchers
     new Routes(itemRegistry, pssRegistry, apiKeyRegistry,
       smrRegistryS3Success).applicationRoutes
 
+  val esQueryParseErrorClient =
+    testKit.spawn(MockEsClientQueryParseError())
+  val itemSearchWithParseError =
+    MockItemSearch(testKit, Some(esQueryParseErrorClient))
+  val itemRegistryWithParseError =
+    MockItemRegistry(testKit, authenticator, itemAnalyticsClient,
+      Some(itemSearchWithParseError))
+  val routesWithParseError: Route =
+    new Routes(itemRegistryWithParseError, pssRegistry, apiKeyRegistry,
+      smrRegistryS3Success).applicationRoutes
+
   "malformed api_key" should {
     "return Forbidden for a key that is too short" in {
       val request = Get("/v2/items?api_key=tooshort")
@@ -93,4 +105,14 @@ class InvalidParamsTest extends AnyWordSpec with Matchers
       }
     }
   }
+
+  "Elasticsearch query parse error" should {
+    "return BadRequest for /v2/items" in {
+      val request = Get(s"/v2/items?api_key=$fakeApiKey&q=invalid%29-")
+      request ~> Route.seal(routesWithParseError) ~> check {
+        status shouldEqual StatusCodes.BadRequest
+        contentType should === (ContentTypes.`application/json`)
+      }
+    }
+  }
 }

src/test/scala/dpla/api/v2/search/MockEsClientQueryParseError.scala

@@ -0,0 +1,29 @@
+package dpla.api.v2.search
+
+import akka.actor.typed.Behavior
+import akka.actor.typed.scaladsl.Behaviors
+import dpla.api.v2.search.SearchProtocol.{
+  IntermediateSearchResult,
+  RandomQuery,
+  SearchQuery,
+  SearchQueryParseFailure
+}
+
+object MockEsClientQueryParseError {
+
+  def apply(): Behavior[IntermediateSearchResult] = {
+    Behaviors.receiveMessage[IntermediateSearchResult] {
+
+      case SearchQuery(_, _, replyTo) =>
+        replyTo ! SearchQueryParseFailure
+        Behaviors.same
+
+      case RandomQuery(_, _, replyTo) =>
+        replyTo ! SearchQueryParseFailure
+        Behaviors.same
+
+      case _ =>
+        Behaviors.unhandled
+    }
+  }
+}