HelloWSContextListener.java

package quarkus.graphql.test;

import java.util.Set;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import javax.websocket.Endpoint;
import javax.websocket.HandshakeResponse;
import javax.websocket.server.HandshakeRequest;
import javax.websocket.server.ServerApplicationConfig;
import javax.websocket.server.ServerContainer;
import javax.websocket.server.ServerEndpointConfig;

import graphql.execution.AsyncExecutionStrategy;
import graphql.execution.SubscriptionExecutionStrategy;
import graphql.schema.GraphQLSchema;
import graphql.schema.StaticDataFetcher;
import graphql.schema.idl.RuntimeWiring;
import graphql.schema.idl.SchemaGenerator;
import graphql.schema.idl.SchemaParser;
import graphql.schema.idl.TypeDefinitionRegistry;
import graphql.servlet.GraphQLWebsocketServlet;
import graphql.servlet.config.DefaultExecutionStrategyProvider;
import graphql.servlet.config.DefaultGraphQLSchemaProvider;
import graphql.servlet.config.ExecutionStrategyProvider;
import graphql.servlet.core.GraphQLObjectMapper;
import graphql.servlet.core.GraphQLQueryInvoker;
import graphql.servlet.input.GraphQLInvocationInputFactory;


//Inspired from https://github.com/graphql-java-kickstart/graphql-spring-boot/blob/master/graphql-spring-boot-autoconfigure/src/main/java/com/oembedler/moon/graphql/boot/GraphQLWebAutoConfiguration.java
//Background https://github.com/quarkusio/quarkus/issues/3691

@WebListener
public class HelloWSContextListener implements ServletContextListener, ServerApplicationConfig {

    private static GraphQLWebsocketServlet servlet;

    /* @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        final ServerContainer serverContainer = (ServerContainer) servletContextEvent.getServletContext().getAttribute("javax.websocket.server.ServerContainer");
    
        try {
            servlet = configureServlet();
            ServerEndpointConfig endpointConfiguration = ServerEndpointConfig.Builder.create(GraphQLWebsocketServlet.class, "/graphql-ws2").configurator(new HelloEndpointConfigurator(servlet)).build();
            serverContainer.addEndpoint(endpointConfiguration);
        } catch (DeploymentException e) {
            e.printStackTrace();
        }
    }*/

    @Override
    public Set<ServerEndpointConfig> getEndpointConfigs(Set<Class<? extends Endpoint>> endpointClasses) {
        servlet = configureServlet();
        ServerEndpointConfig endpointConfiguration = ServerEndpointConfig.Builder.create(GraphQLWebsocketServlet.class, "/graphql-ws").configurator(new HelloEndpointConfigurator(servlet)).build();
        return Set.of(endpointConfiguration);
    }

    private GraphQLWebsocketServlet configureServlet() {
        String schema = "type Query{hello: String}";

        SchemaParser schemaParser = new SchemaParser();
        TypeDefinitionRegistry typeDefinitionRegistry = schemaParser.parse(schema);

        RuntimeWiring runtimeWiring = RuntimeWiring.newRuntimeWiring().type("Query", builder -> builder.dataFetcher("hello", new StaticDataFetcher("world!!"))).build();

        SchemaGenerator schemaGenerator = new SchemaGenerator();
        GraphQLSchema graphQLSchema = schemaGenerator.makeExecutableSchema(typeDefinitionRegistry, runtimeWiring);

        GraphQLInvocationInputFactory invocationInputFactory = GraphQLInvocationInputFactory.newBuilder(new DefaultGraphQLSchemaProvider(graphQLSchema)).build();

        ExecutionStrategyProvider executionStrategyProvider = new DefaultExecutionStrategyProvider(new AsyncExecutionStrategy(), new AsyncExecutionStrategy(), new SubscriptionExecutionStrategy());
        GraphQLQueryInvoker queryInvoker = GraphQLQueryInvoker.newBuilder().withExecutionStrategyProvider(executionStrategyProvider).build();

        GraphQLObjectMapper graphQLObjectMapper = GraphQLObjectMapper.newBuilder().build();

        return new GraphQLWebsocketServlet(queryInvoker, invocationInputFactory, graphQLObjectMapper);

    }

    @Override
    public Set<Class<?>> getAnnotatedEndpointClasses(Set<Class<?>> scanned) {
        return Set.of();
    }

    public void contextDestroyed(ServletContextEvent servletContextEvent) {
        if (servlet != null && !servlet.isShutDown()) {
            servlet.beginShutDown();
            servlet = null;
        }
    }

    public class HelloEndpointConfigurator extends ServerEndpointConfig.Configurator {
        private GraphQLWebsocketServlet servlet;

        public HelloEndpointConfigurator(GraphQLWebsocketServlet servlet) {
            this.servlet = servlet;
        }

        @SuppressWarnings("unchecked")
        @Override
        public <T> T getEndpointInstance(Class<T> clazz) throws InstantiationException {
            return (T) servlet;
        }

        @Override
        public void modifyHandshake(ServerEndpointConfig sec, HandshakeRequest request, HandshakeResponse response) {
            servlet.modifyHandshake(sec, request, response);
        }

    }

}