Generate context with suspend and nullable in subscriptions (#1053)

* Generate context with suspend and nullable in subscriptions

* Update tests

* Do not cache null context for subscriptions

* Rename internal methods

* WIP

* Update subsctiption javadocs

* Use expression body

* Update docs for context

Co-authored-by: Shane Myrick <[email protected]>

Author: smyrick

examples/build.gradle.kts

@@ -40,6 +40,7 @@ subprojects {
 
     val kotlinVersion: String by project
     val junitVersion: String by project
+    val kotlinCoroutinesVersion: String by project
 
     val detektVersion: String by project
     val ktlintVersion: String by project
@@ -50,6 +51,8 @@ subprojects {
 
     dependencies {
         implementation(kotlin("stdlib", kotlinVersion))
+        implementation(kotlin("reflect", kotlinVersion))
+        implementation("org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:$kotlinCoroutinesVersion")
         testImplementation(kotlin("test-junit5", kotlinVersion))
         testImplementation("org.junit.jupiter:junit-jupiter-api:$junitVersion")
         testImplementation("org.junit.jupiter:junit-jupiter-engine:$junitVersion")

examples/server/ktor-server/src/main/kotlin/com/expediagroup/graphql/examples/server/ktor/KtorGraphQLContextFactory.kt

@@ -25,7 +25,7 @@ import io.ktor.request.ApplicationRequest
  */
 class KtorGraphQLContextFactory : GraphQLContextFactory<AuthorizedContext, ApplicationRequest> {
 
-    override fun generateContext(request: ApplicationRequest): AuthorizedContext {
+    override suspend fun generateContext(request: ApplicationRequest): AuthorizedContext {
         val loggedInUser = User(
             email = "[email protected]",
             firstName = "Someone",

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/context/MyGraphQLContext.kt

@@ -24,14 +24,14 @@ import org.springframework.web.reactive.socket.WebSocketSession
  * Simple [GraphQLContext] that holds extra value and the [ServerRequest]
  */
 class MyGraphQLContext(
-    val myCustomValue: String,
-    val request: ServerRequest
+    val request: ServerRequest,
+    val myCustomValue: String
 ) : GraphQLContext
 
 /**
  * Simple [GraphQLContext] that holds extra value and the [WebSocketSession]
  */
 class MySubscriptionGraphQLContext(
     val request: WebSocketSession,
-    var subscriptionValue: String? = null
+    var auth: String? = null
 ) : GraphQLContext

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/context/MyGraphQLContextFactory.kt

@@ -29,17 +29,20 @@ import org.springframework.web.reactive.socket.WebSocketSession
 @Component
 class MyGraphQLContextFactory : SpringGraphQLContextFactory<MyGraphQLContext>() {
 
-    override fun generateContext(request: ServerRequest): MyGraphQLContext = MyGraphQLContext(
-        myCustomValue = request.headers().firstHeader("MyHeader") ?: "defaultContext",
-        request = request
+    override suspend fun generateContext(request: ServerRequest): MyGraphQLContext = MyGraphQLContext(
+        request = request,
+        myCustomValue = request.headers().firstHeader("MyHeader") ?: "defaultContext"
     )
 }
 
+/**
+ * [GraphQLContextFactory] that generates [MySubscriptionGraphQLContext] that will be available when processing subscription operations.
+ */
 @Component
 class MySubscriptionGraphQLContextFactory : SpringSubscriptionGraphQLContextFactory<MySubscriptionGraphQLContext>() {
 
-    override fun generateContext(request: WebSocketSession): MySubscriptionGraphQLContext = MySubscriptionGraphQLContext(
+    override suspend fun generateContext(request: WebSocketSession): MySubscriptionGraphQLContext = MySubscriptionGraphQLContext(
         request = request,
-        subscriptionValue = null
+        auth = null
     )
 }

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/execution/MySubscriptionHooks.kt

@@ -19,9 +19,7 @@ package com.expediagroup.graphql.examples.server.spring.execution
 import com.expediagroup.graphql.examples.server.spring.context.MySubscriptionGraphQLContext
 import com.expediagroup.graphql.generator.execution.GraphQLContext
 import com.expediagroup.graphql.server.spring.subscriptions.ApolloSubscriptionHooks
-import kotlinx.coroutines.reactor.mono
 import org.springframework.web.reactive.socket.WebSocketSession
-import reactor.core.publisher.Mono
 
 /**
  * A simple implementation of Apollo Subscription Lifecycle Events.
@@ -31,12 +29,11 @@ class MySubscriptionHooks : ApolloSubscriptionHooks {
     override fun onConnect(
         connectionParams: Map<String, String>,
         session: WebSocketSession,
-        graphQLContext: GraphQLContext
-    ): Mono<GraphQLContext> = mono {
-        if (graphQLContext is MySubscriptionGraphQLContext) {
-            val bearer = connectionParams["Authorization"] ?: "none"
-            graphQLContext.subscriptionValue = bearer
+        graphQLContext: GraphQLContext?
+    ): GraphQLContext? {
+        if (graphQLContext != null && graphQLContext is MySubscriptionGraphQLContext) {
+            graphQLContext.auth = connectionParams["Authorization"]
         }
-        graphQLContext
+        return graphQLContext
     }
 }

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/subscriptions/SimpleSubscription.kt

@@ -82,5 +82,5 @@ class SimpleSubscription : Subscription {
 
     @GraphQLDescription("Returns a value from the subscription context")
     fun subscriptionContext(myGraphQLContext: MySubscriptionGraphQLContext): Flux<String> =
-        Flux.just(myGraphQLContext.subscriptionValue ?: "", "value 2", "value3")
+        Flux.just(myGraphQLContext.auth ?: "no-auth")
 }

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/execution/FunctionDataFetcher.kt

@@ -59,7 +59,7 @@ open class FunctionDataFetcher(
      * Invoke a suspend function or blocking function, passing in the [target] if not null or default to using the source from the environment.
      */
     override fun get(environment: DataFetchingEnvironment): Any? {
-        val instance = target ?: environment.getSource<Any?>()
+        val instance: Any? = target ?: environment.getSource<Any?>()
         val instanceParameter = fn.instanceParameter
 
         return if (instance != null && instanceParameter != null) {

generator/graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/execution/GraphQLContext.kt

@@ -16,19 +16,8 @@
 
 package com.expediagroup.graphql.generator.execution
 
-import java.util.concurrent.ConcurrentHashMap
-import java.util.concurrent.ConcurrentMap
-
 /**
  * Marker interface to indicate that the implementing class should be considered
  * as the GraphQL context. This means the implementing class will not appear in the schema.
  */
 interface GraphQLContext
-
-/**
- * Default [GraphQLContext] that can be used if there is none provided. Exposes generic concurrent hash map
- * that can be populated with custom data.
- */
-class DefaultGraphQLContext : GraphQLContext {
-    val contents: ConcurrentMap<Any, Any> = ConcurrentHashMap()
-}

servers/graphql-kotlin-server/src/main/kotlin/com/expediagroup/graphql/server/execution/GraphQLContextFactory.kt

@@ -16,7 +16,6 @@
 
 package com.expediagroup.graphql.server.execution
 
-import com.expediagroup.graphql.generator.execution.DefaultGraphQLContext
 import com.expediagroup.graphql.generator.execution.GraphQLContext
 
 /**
@@ -28,12 +27,5 @@ interface GraphQLContextFactory<out Context : GraphQLContext, Request> {
      * Generate GraphQL context based on the incoming request and the corresponding response.
      * If no context should be generated and used in the request, return null.
      */
-    fun generateContext(request: Request): Context?
-}
-
-/**
- * Default context factory that generates GraphQL context with empty concurrent map that can store any elements.
- */
-class DefaultGraphQLContextFactory<T> : GraphQLContextFactory<DefaultGraphQLContext, T> {
-    override fun generateContext(request: T) = DefaultGraphQLContext()
+    suspend fun generateContext(request: Request): Context?
 }

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

@@ -16,7 +16,6 @@
 
 package com.expediagroup.graphql.server.extensions
 
-import com.expediagroup.graphql.generator.execution.DefaultGraphQLContext
 import com.expediagroup.graphql.types.GraphQLRequest
 import graphql.ExecutionInput
 import org.dataloader.DataLoaderRegistry
@@ -29,6 +28,6 @@ fun GraphQLRequest.toExecutionInput(graphQLContext: Any? = null, dataLoaderRegis
         .query(this.query)
         .operationName(this.operationName)
         .variables(this.variables ?: emptyMap())
-        .context(graphQLContext ?: DefaultGraphQLContext())
+        .context(graphQLContext)
         .dataLoaderRegistry(dataLoaderRegistry ?: DataLoaderRegistry())
         .build()