GraphQL ID example (#55)

* Support GraphQLID for input types

* Add example of query and mutation using Scalar ID type

Author: gscheibel

example/src/main/kotlin/com.expedia.graphql.sample/query/CustomScalarQuery.kt

@@ -0,0 +1,31 @@
+package com.expedia.graphql.sample.query
+
+import com.expedia.graphql.annotations.GraphQLDescription
+import com.expedia.graphql.annotations.GraphQLID
+import com.expedia.graphql.sample.mutation.Mutation
+import org.springframework.stereotype.Component
+import java.util.UUID
+
+/**
+ * Simple query that exposes custom scalar.
+ */
+@Component
+class ScalarQuery: Query {
+
+    @GraphQLDescription("generates random UUID")
+    fun generateRandomUUID() = UUID.randomUUID()
+
+    fun findPersonById(id: Int) = Person(id, "Nelson")
+}
+
+@Component
+class ScalarMutation : Mutation {
+    fun addPerson(person: Person): Person = person
+}
+
+data class Person(
+    @property:GraphQLID
+    val id: Int,
+
+    val name: String
+)

example/src/main/kotlin/com.expedia.graphql.sample/query/ScalarQuery.kt

@@ -265,7 +265,7 @@ internal class SchemaGenerator(
 
         builder.description(prop.graphQLDescription())
         builder.name(prop.name)
-        builder.type(graphQLTypeOf(prop.returnType, true) as GraphQLInputType)
+        builder.type(graphQLTypeOf(prop.returnType, true, prop.isGraphQLID()) as GraphQLInputType)
 
         return builder.build()
     }

src/main/kotlin/com/expedia/graphql/schema/generator/SchemaGenerator.kt

@@ -10,6 +10,7 @@ import com.expedia.graphql.schema.extensions.deepName
 import com.expedia.graphql.schema.testSchemaConfig
 import com.expedia.graphql.toSchema
 import graphql.GraphQL
+import graphql.Scalars
 import graphql.schema.GraphQLNonNull
 import graphql.schema.GraphQLObjectType
 import org.junit.jupiter.api.Assertions.assertNull
@@ -248,10 +249,10 @@ class SchemaGeneratorTest {
         val schema = toSchema(queries = listOf(TopLevelObjectDef(QueryWithId())), config = testSchemaConfig)
 
         val placeType = schema.getObjectType("PlaceOfIds")
-        assertEquals(graphql.Scalars.GraphQLID, (placeType.getFieldDefinition("intId").type as? GraphQLNonNull)?.wrappedType)
-        assertEquals(graphql.Scalars.GraphQLID, (placeType.getFieldDefinition("longId").type as? GraphQLNonNull)?.wrappedType)
-        assertEquals(graphql.Scalars.GraphQLID, (placeType.getFieldDefinition("stringId").type as? GraphQLNonNull)?.wrappedType)
-        assertEquals(graphql.Scalars.GraphQLID, (placeType.getFieldDefinition("uuid").type as? GraphQLNonNull)?.wrappedType)
+        assertEquals(Scalars.GraphQLID, (placeType.getFieldDefinition("intId").type as? GraphQLNonNull)?.wrappedType)
+        assertEquals(Scalars.GraphQLID, (placeType.getFieldDefinition("longId").type as? GraphQLNonNull)?.wrappedType)
+        assertEquals(Scalars.GraphQLID, (placeType.getFieldDefinition("stringId").type as? GraphQLNonNull)?.wrappedType)
+        assertEquals(Scalars.GraphQLID, (placeType.getFieldDefinition("uuid").type as? GraphQLNonNull)?.wrappedType)
     }
 
     @Test
@@ -263,6 +264,15 @@ class SchemaGeneratorTest {
         assertEquals("Person is not a valid ID type, only [kotlin.Int, kotlin.String, kotlin.Long, java.util.UUID] are accepted", exception.message)
     }
 
+    @Test
+    fun `SchemaGenerator supports Scalar GraphQLID for input types`() {
+        val schema = toSchema(mutations = listOf(TopLevelObjectDef(MutationWithId())), config = testSchemaConfig)
+
+        val furnitureType = schema.getObjectType("Furniture")
+        val serialField = furnitureType.getFieldDefinition("serial").type as? GraphQLNonNull
+        assertEquals(Scalars.GraphQLID, serialField?.wrappedType)
+    }
+
     class QueryObject {
         @GraphQLDescription("A GraphQL query method")
         fun query(@GraphQLDescription("A GraphQL value") value: Int): Geography = Geography(value, GeoType.CITY, listOf())
@@ -407,4 +417,13 @@ class SchemaGeneratorTest {
     class QueryWithInvalidId {
         fun query(): InvalidIds = InvalidIds(Person("person id not a valid type id"))
     }
+
+    class MutationWithId {
+        fun mutate(furniture: Furniture): Furniture = furniture
+    }
+
+    data class Furniture(
+        @property:GraphQLID val serial: UUID,
+        val type: String
+    )
 }