use legacy keep alive message as needed (#297)

don't send keep alive until the connection is established

.npmignore

@@ -1,2 +1,2 @@
 dist/test
-src
+src

src/message-types.ts

@@ -46,6 +46,10 @@ export default class MessageTypes {
    * @deprecated
    */
   public static INIT_FAIL = 'init_fail';
+  /**
+   * @deprecated
+   */
+  public static KEEP_ALIVE = 'keepalive';
 
   constructor() {
     throw new Error('Static Class');

src/server.ts

@@ -146,17 +146,6 @@ export class SubscriptionServer {
       connectionContext.socket = socket;
       connectionContext.operations = {};
 
-      // Regular keep alive messages if keepAlive is set
-      if (this.keepAlive) {
-        const keepAliveTimer = setInterval(() => {
-          if (socket.readyState === WebSocket.OPEN) {
-            this.sendMessage(connectionContext, undefined, MessageTypes.GQL_CONNECTION_KEEP_ALIVE, undefined);
-          } else {
-            clearInterval(keepAliveTimer);
-          }
-        }, this.keepAlive);
-      }
-
       const connectionClosedHandler = (error: any) => {
         if (error) {
           this.sendError(
@@ -282,12 +271,15 @@ export class SubscriptionServer {
             );
 
             if (this.keepAlive) {
-              this.sendMessage(
-                connectionContext,
-                undefined,
-                MessageTypes.GQL_CONNECTION_KEEP_ALIVE,
-                undefined,
-              );
+              this.sendKeepAlive(connectionContext);
+              // Regular keep alive messages if keepAlive is set
+              const keepAliveTimer = setInterval(() => {
+                if (connectionContext.socket.readyState === WebSocket.OPEN) {
+                  this.sendKeepAlive(connectionContext);
+                } else {
+                  clearInterval(keepAliveTimer);
+                }
+              }, this.keepAlive);
             }
           }).catch((error: Error) => {
             this.sendError(
@@ -461,6 +453,14 @@ export class SubscriptionServer {
     };
   }
 
+  private sendKeepAlive(connectionContext: ConnectionContext): void {
+    if (connectionContext.isLegacy) {
+      this.sendMessage(connectionContext, undefined, MessageTypes.KEEP_ALIVE, undefined);
+    } else {
+      this.sendMessage(connectionContext, undefined, MessageTypes.GQL_CONNECTION_KEEP_ALIVE, undefined);
+    }
+  }
+
   private sendMessage(connectionContext: ConnectionContext, opId: string, type: string, payload: any): void {
     const parsedMessage = parseLegacyProtocolMessage(connectionContext, {
       type,

src/test/tests.ts

@@ -1941,12 +1941,39 @@ describe('Server', function () {
       const parsedMessage = JSON.parse(message.data);
       if (parsedMessage.type === MessageTypes.GQL_CONNECTION_KEEP_ALIVE) {
         yieldCount += 1;
-        if (yieldCount > 1) {
+        if (yieldCount > 2) {
           client.close();
           done();
         }
       }
     };
+    client.onopen = () => {
+      client.send(JSON.stringify({
+        id: 1,
+        type: MessageTypes.GQL_CONNECTION_INIT,
+      }));
+    };
+  });
+
+  it('sends legacy keep alive signal in the socket', function (done) {
+    let client = new WebSocket(`ws://localhost:${KEEP_ALIVE_TEST_PORT}/`, GRAPHQL_SUBSCRIPTIONS);
+    let yieldCount = 0;
+    client.onmessage = (message: any) => {
+      const parsedMessage = JSON.parse(message.data);
+      if (parsedMessage.type === MessageTypes.KEEP_ALIVE) {
+        yieldCount += 1;
+        if (yieldCount > 2) {
+          client.close();
+          done();
+        }
+      }
+    };
+    client.onopen = () => {
+      client.send(JSON.stringify({
+        id: 1,
+        type: MessageTypes.INIT,
+      }));
+    };
   });
 });