include Playground IDE in graphql-kotlin-spring-server (#377)

Include [Prisma Labs Playground IDE](https://github.com/prisma-labs/graphql-playground) in `graphql-kotlin-spring-server` auto-configuration library.

By default, playground will be enabled under `/playground` route. You can disable it by specifying `graphql.playground.enabled=false` property. Similarly default endpoint can be changed by setting new value to the `graphql.playground.endpoint` property.

Author: aarestu

examples/federation/extend-app/src/main/resources/graphql-playground.html

@@ -2,3 +2,7 @@ graphql:
   subscriptions:
     # Send a ka message every 1000 ms (1 second)
     keepAliveInterval: 1000
+
+  playground:
+    enabled: true
+    endpoint: "/"

examples/spring/src/main/resources/application.yml

@@ -47,7 +47,8 @@ import java.util.Optional
     RoutesConfiguration::class,
     SchemaAutoConfiguration::class,
     FederationAutoConfiguration::class,
-    SubscriptionAutoConfiguration::class
+    SubscriptionAutoConfiguration::class,
+    PlaygroundAutoConfiguration::class
 )
 @EnableConfigurationProperties(GraphQLConfigurationProperties::class)
 class GraphQLAutoConfiguration {

examples/spring/src/main/resources/graphql-playground.html

@@ -29,6 +29,7 @@ class GraphQLConfigurationProperties {
     var packages: List<String> = emptyList()
     var federation: FederationConfigurationProperties = FederationConfigurationProperties()
     var subscriptions: SubscriptionConfigurationProperties = SubscriptionConfigurationProperties()
+    var playground: PlaygroundConfigurationProperties = PlaygroundConfigurationProperties()
 }
 
 /**
@@ -48,3 +49,13 @@ class SubscriptionConfigurationProperties {
     /** Keep the websocket alive and send a message to the client every interval in ms. Default to not sending messages */
     var keepAliveInterval: Long? = null
 }
+
+/**
+ * Playground configuration properties.
+ */
+class PlaygroundConfigurationProperties {
+    /** Boolean flag indicating whether to enabled Prisma Labs Playground GraphQL IDE */
+    var enabled: Boolean = true
+    /** Prisma Labs Playground GraphQL IDE endpoint, defaults to "/playground" */
+    var endpoint: String = "/playground"
+}

graphql-kotlin-spring-server/src/main/kotlin/com/expediagroup/graphql/spring/GraphQLAutoConfiguration.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2019 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.spring
+
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.core.io.Resource
+import org.springframework.web.reactive.function.server.RouterFunction
+import org.springframework.web.reactive.function.server.ServerResponse
+import org.springframework.web.reactive.function.server.coRouter
+import org.springframework.web.reactive.function.server.html
+import org.springframework.web.reactive.function.server.bodyAndAwait
+
+/**
+ * SpringBoot auto configuration for generating Playground Service.
+ */
+@ConditionalOnProperty(value = ["graphql.playground.enabled"], havingValue = "true", matchIfMissing = true)
+@Configuration
+class PlaygroundAutoConfiguration(
+    private val config: GraphQLConfigurationProperties,
+    @Value("classpath:/graphql-playground.html") private val playgroundHtml: Resource
+) {
+
+    @Bean
+    @ExperimentalCoroutinesApi
+    fun playgroundRoute(): RouterFunction<ServerResponse> {
+        val body = playgroundHtml.inputStream.bufferedReader().use { reader ->
+            reader.readText()
+                .replace("\${graphQLEndpoint}", config.endpoint)
+                .replace("\${subscriptionsEndpoint}", config.subscriptions.endpoint)
+        }
+        return coRouter {
+            GET(config.playground.endpoint) {
+                ok().html().bodyAndAwait(body)
+            }
+        }
+    }
+}

graphql-kotlin-spring-server/src/main/kotlin/com/expediagroup/graphql/spring/GraphQLConfigurationProperties.kt

@@ -27,6 +27,18 @@
       "type": "java.lang.Long",
       "defaultValue": "null",
       "sourceType": "com.expediagroup.graphql.spring.SubscriptionConfigurationProperties"
+    },
+    {
+      "name": "graphql.playground.enabled",
+      "type": "java.lang.Boolean",
+      "sourceType": "com.expediagroup.graphql.spring.PlaygroundConfigurationProperties",
+      "defaultValue": true
+    },
+    {
+      "name": "graphql.playground.endpoint",
+      "type": "java.lang.String",
+      "sourceType": "com.expediagroup.graphql.spring.PlaygroundConfigurationProperties",
+      "defaultValue": "/playground"
     }
   ]
 }

graphql-kotlin-spring-server/src/main/kotlin/com/expediagroup/graphql/spring/PlaygroundAutoConfiguration.kt

@@ -50,7 +50,8 @@
 </div>
 <script>window.addEventListener('load', function (event) {
     GraphQLPlayground.init(document.getElementById('root'), {
-        endpoint: '/graphql'
+        endpoint: '/${graphQLEndpoint}',
+        subscriptionEndpoint: '/${subscriptionsEndpoint}'
     })
 })</script>
 </body>