SubscriptionException for onConnect and enable keep alive by default

Author: oliemansm

src/main/java/graphql/servlet/ApolloSubscriptionConnectionListener.java

@@ -7,10 +7,10 @@ public interface ApolloSubscriptionConnectionListener extends SubscriptionConnec
     String CONNECT_RESULT_KEY = "CONNECT_RESULT";
 
     default boolean isKeepAliveEnabled() {
-        return false;
+        return true;
     }
 
-    default Optional<Object> onConnect(Object payload) {
+    default Optional<Object> onConnect(Object payload) throws SubscriptionException {
         return Optional.empty();
     }
 

src/main/java/graphql/servlet/SubscriptionException.java

@@ -0,0 +1,18 @@
+package graphql.servlet;
+
+public class SubscriptionException extends Exception {
+
+    private Object payload;
+
+    public SubscriptionException() {
+    }
+
+    public SubscriptionException(Object payload) {
+        this.payload = payload;
+    }
+
+    public Object getPayload() {
+        return payload;
+    }
+
+}

src/main/java/graphql/servlet/internal/ApolloSubscriptionProtocolHandler.java

@@ -6,6 +6,7 @@
 import graphql.ExecutionResult;
 import graphql.servlet.ApolloSubscriptionConnectionListener;
 import graphql.servlet.GraphQLSingleInvocationInput;
+import graphql.servlet.SubscriptionException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -63,8 +64,8 @@ public void onMessage(HandshakeRequest request, Session session, WsSessionSubscr
                 try {
                     Optional<Object> connectionResponse = connectionListener.onConnect(message.getPayload());
                     connectionResponse.ifPresent(it -> session.getUserProperties().put(ApolloSubscriptionConnectionListener.CONNECT_RESULT_KEY, it));
-                } catch (Throwable t) {
-                    sendMessage(session, OperationMessage.Type.GQL_CONNECTION_ERROR, message.getId(), t);
+                } catch (SubscriptionException e) {
+                    sendMessage(session, OperationMessage.Type.GQL_CONNECTION_ERROR, message.getId(), e.getPayload());
                     return;
                 }