feat: DataFetchingEnvironment extensions to access to entries in GraphQLContext (ExpediaGroup#1552) (ExpediaGroup#1553)

* feat: DataFetchingEnvironment extensions to access to data in GraphQLContext

* feat: add copyright

Author: samuelAndalon

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/exceptions/KeyNotFoundInGraphQLContextException.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2022 Expedia, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.expediagroup.graphql.generator.exceptions
+
+import graphql.GraphQLContext
+import kotlin.reflect.KClass
+
+/**
+ * Thrown when [klazz] key was not found in a [GraphQLContext]
+ */
+class KeyNotFoundInGraphQLContextException(klazz: KClass<*>) : GraphQLKotlinException("GraphQLContext does not contain key ${klazz.simpleName}")

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/extensions/GraphQLContextExtensions.kt

@@ -16,24 +16,35 @@
 
 package com.expediagroup.graphql.generator.extensions
 
+import com.expediagroup.graphql.generator.exceptions.KeyNotFoundInGraphQLContextException
 import graphql.GraphQLContext
 
 /**
  * Returns a value in the context by KClass key
  * @return a value or null
  */
-inline fun <reified T> GraphQLContext.get(): T? = get(T::class)
+inline fun <reified T> GraphQLContext.get(): T? =
+    get(T::class)
 
 /**
  * Returns a value in the context by KClass key
  * @param defaultValue the default value to use if there is no KClass key entry
  * @return a value or default value
  */
-inline fun <reified T> GraphQLContext.getOrDefault(defaultValue: T): T = getOrDefault(T::class, defaultValue)
+inline fun <reified T> GraphQLContext.getOrDefault(defaultValue: T): T =
+    getOrDefault(T::class, defaultValue)
 
 /**
  * Returns a value in the context by KClass key
  * @param defaultValue function to invoke if there is no KClass key entry
  * @return a value or result of [defaultValue] function
  */
-inline fun <reified T> GraphQLContext.getOrElse(defaultValue: () -> T): T = get(T::class) ?: defaultValue.invoke()
+inline fun <reified T> GraphQLContext.getOrElse(defaultValue: () -> T): T =
+    get(T::class) ?: defaultValue.invoke()
+
+/**
+ * Returns a value in the context by KClass key or [KeyNotFoundInGraphQLContextException] if key was not found
+ * @return a value or [KeyNotFoundInGraphQLContextException]
+ */
+inline fun <reified T> GraphQLContext.getOrThrow(): T =
+    get(T::class) ?: throw KeyNotFoundInGraphQLContextException(T::class)

servers/graphql-kotlin-server/src/main/kotlin/com/expediagroup/graphql/server/extensions/dataFetchingEnvironmentExtensions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,11 @@
 
 package com.expediagroup.graphql.server.extensions
 
+import com.expediagroup.graphql.generator.exceptions.KeyNotFoundInGraphQLContextException
+import com.expediagroup.graphql.generator.extensions.get
+import com.expediagroup.graphql.generator.extensions.getOrDefault
+import com.expediagroup.graphql.generator.extensions.getOrElse
+import com.expediagroup.graphql.generator.extensions.getOrThrow
 import com.expediagroup.graphql.server.exception.MissingDataLoaderException
 import graphql.schema.DataFetchingEnvironment
 import java.util.concurrent.CompletableFuture
@@ -25,17 +30,44 @@ import java.util.concurrent.CompletableFuture
  * The provided key should be the cache key object used to save the value for that particular data loader.
  */
 fun <K, V> DataFetchingEnvironment.getValueFromDataLoader(dataLoaderName: String, key: K): CompletableFuture<V> {
-    val loader = getLoaderName<K, V>(dataLoaderName)
+    val loader = getDataLoader<K, V>(dataLoaderName) ?: throw MissingDataLoaderException(dataLoaderName)
     return loader.load(key, this.getContext())
 }
 
 /**
 * Helper method to get values from a registered DataLoader.
 */
 fun <K, V> DataFetchingEnvironment.getValuesFromDataLoader(dataLoaderName: String, keys: List<K>): CompletableFuture<List<V>> {
-    val loader = getLoaderName<K, V>(dataLoaderName)
+    val loader = getDataLoader<K, V>(dataLoaderName) ?: throw MissingDataLoaderException(dataLoaderName)
     return loader.loadMany(keys, listOf(this.getContext()))
 }
 
-private fun <K, V> DataFetchingEnvironment.getLoaderName(dataLoaderName: String) =
-    this.getDataLoader<K, V>(dataLoaderName) ?: throw MissingDataLoaderException(dataLoaderName)
+/**
+ * Returns a value from the graphQLContext by KClass key
+ * @return a value or null
+ */
+inline fun <reified T> DataFetchingEnvironment.getFromContext(): T? =
+    graphQlContext.get<T>()
+
+/**
+ * Returns a value from the graphQLContext by KClass key
+ * @param defaultValue the default value to use if there is no KClass key entry
+ * @return a value or default value
+ */
+inline fun <reified T> DataFetchingEnvironment.getFromContextOrDefault(defaultValue: T): T =
+    graphQlContext.getOrDefault(defaultValue)
+
+/**
+ * Returns a value from the graphQLContext by KClass key
+ * @param defaultValue function to invoke if there is no KClass key entry
+ * @return a value or result of [defaultValue] function
+ */
+inline fun <reified T> DataFetchingEnvironment.getFromContextOrElse(defaultValue: () -> T): T =
+    graphQlContext.getOrElse(defaultValue)
+
+/**
+ * Returns a value from the graphQLContext by KClass key or [KeyNotFoundInGraphQLContextException] if key was not found
+ * @return a value or [KeyNotFoundInGraphQLContextException]
+ */
+inline fun <reified T> DataFetchingEnvironment.getFromContextOrThrow(): T =
+    graphQlContext.getOrThrow()