Add update cache methods to Fetcher

src/main/scala/sangria/execution/deferred/Fetcher.scala

@@ -33,6 +33,12 @@ class Fetcher[Ctx, Res, RelRes, Id](
   def clearCachedRelId[RelId](deferredResolverState: Any, rel: Relation[Res, _, RelId], relId: RelId) =
     findCache(deferredResolverState)(_.clearRelId(rel, relId))
 
+  def updateCache(deferredResolverState: Any, id: Id, value: Res) =
+    findCache(deferredResolverState)(_.update(id, value))
+
+  def updateCacheRel[RelId](deferredResolverState: Any, rel: Relation[Res, _, RelId], relId: RelId, values: Seq[Res]) =
+    findCache(deferredResolverState)(_.updateRel(rel, relId, idFn, values))
+
   private def findCache(deferredResolverState: Any)(op: FetcherCache ⇒ Unit): Unit =
     deferredResolverState match {
       case map: Map[AnyRef, FetcherCache] @unchecked ⇒ map.get(this) match {
@@ -243,4 +249,4 @@ case class FetcherContext[Ctx](
 
 class RelationNotSupportedError extends Exception(s"Relations are not supported by Fetcher.")
 
-class RelationOnlySupportedError extends Exception(s"Only relations are supported by Fetcher.")
+class RelationOnlySupportedError extends Exception(s"Only relations are supported by Fetcher.")

src/test/scala/sangria/execution/deferred/FetcherSpec.scala

@@ -131,6 +131,14 @@ class FetcherSpec extends WordSpec with Matchers with FutureResultSupport {
         Field("categoryEager", OptionType(CategoryType),
           arguments = Argument("id", StringType) :: Nil,
           resolve = c ⇒ c.ctx.getCategory(c.arg[String]("id"))),
+        Field("categoryAndCacheEmptyProducts", CategoryType,
+          arguments = Argument("id", StringType) :: Nil,
+          resolve = c ⇒ DeferredValue(fetcherCat.defer(c.arg[String]("id"))) map {
+            cat => {
+              fetcherProd.updateCacheRel(c.deferredResolverState, prodCat, cat.id, Seq())
+              cat
+            }
+          }),
         Field("categoryNonOpt", CategoryType,
           arguments = Argument("id", StringType) :: Nil,
           resolve = c ⇒ fetcherCat.defer(c.arg[String]("id"))),
@@ -414,7 +422,7 @@ class FetcherSpec extends WordSpec with Matchers with FutureResultSupport {
       resRelsOnly should be (resRelsOnlyCached)
     }
 
-    "hansle complex relations" in {
+    "handle complex relations" in {
       val query =
         graphql"""
           {
@@ -939,6 +947,26 @@ class FetcherSpec extends WordSpec with Matchers with FutureResultSupport {
 
       fetchedProdIds.map(_.sorted) should be (Vector(Vector(2)))
     }
+
+    "support manual cache updates at field resolver" in {
+      check(schema(), (), """
+          {
+            categoryAndCacheEmptyProducts(id: "4") {
+              name
+              productRelSeq {
+                name
+              }
+            }
+          }
+        """, Map(
+        "data" → Map(
+          "categoryAndCacheEmptyProducts" → Map(
+            "name" → "Cat 4",
+            "productRelSeq" → Vector(),
+          ))),
+        resolver = defaultResolver,
+        userContext = new Repo)
+    }
   }
 
   "Fetcher" when {
@@ -950,4 +978,4 @@ class FetcherSpec extends WordSpec with Matchers with FutureResultSupport {
       behave like properFetcher (sync.executionContext)
     }
   }
-}
+}