Send all outgoingMessages$ with the latest available open connection

Author: jbmusso

src/GremlinClient.js

@@ -17,6 +17,22 @@ const hasCode = (filterCode) => ({ status: { code } }) => code === filterCode;
 
 const isErrorMessage = ({ status: { code }}) => [200, 204, 206].indexOf(code) === -1;
 
+const serializeToBinary = (message, accept) => {
+  let serializedMessage = accept + JSON.stringify(message);
+  serializedMessage = unescape(encodeURIComponent(serializedMessage));
+
+  // Let's start packing the message into binary
+  // mimeLength(1) + mimeType Length + serializedMessage Length
+  let binaryMessage = new Uint8Array(1 + serializedMessage.length);
+  binaryMessage[0] = accept.length;
+
+  for (let i = 0; i < serializedMessage.length; i++) {
+    binaryMessage[i + 1] = serializedMessage.charCodeAt(i);
+  }
+
+  return binaryMessage;
+}
+
 class GremlinClient extends EventEmitter {
   constructor(port = 8182, host = 'localhost', options = {}) {
     super();
@@ -47,38 +63,37 @@ class GremlinClient extends EventEmitter {
 
     this.commands = {};
 
-    const connection = this.createConnection({
-      port,
-      host,
-      path: this.options.path
-    });
 
     this.commands$ = new Rx.Subject();
     this.commands$.subscribe((command) => {
       const { message: { requestId } } = command;
       this.commands[requestId] = command
     });
 
-    this.registerConnection(connection);
-  }
+    const connection = this.createConnection({
+      port,
+      host,
+      path: this.options.path
+    });
 
-  createConnection({ port, host, path }) {
-    return new WebSocketGremlinConnection({ port, host, path });
-  }
+    const connections$ = Rx.Observable.create((observer) => observer.next(connection));
 
-  registerConnection(connection) {
-    this.connection = connection;
+    const open$ = connections$
+      .flatMap((connection) => Rx.Observable.fromEvent(connection, 'open'));
 
-    const open$ = Rx.Observable.fromEvent(connection, 'open');
-    const error$ = Rx.Observable.fromEvent(connection, 'error');
-    const incomingMessages$ = Rx.Observable.fromEvent(connection, 'message')
+    const error$ = connections$
+      .flatMap((connection) => Rx.Observable.fromEvent(connection, 'error'));
+
+    const incomingMessages$ = connections$
+      .flatMap((connection) => Rx.Observable.fromEvent(connection, 'message'))
       .map(({ data }) => {
         const buffer = new Buffer(data, 'binary');
         const rawMessage = JSON.parse(buffer.toString('utf-8'));
 
         return rawMessage;
       });
-    const close$ = Rx.Observable.fromEvent(connection, 'close');
+    const close$ = connections$
+      .flatMap((connection) => Rx.Observable.fromEvent(connection, 'close'));
 
     const canSend$ = Rx.Observable.merge(
       open$.map(true),
@@ -95,11 +110,18 @@ class GremlinClient extends EventEmitter {
     close$.subscribe((event) => this.handleDisconnection(event));
 
     const outgoingMessages$ = this.commands$
-      .map(({ message }) => message)
-      .pausableBuffered(canSend$);
+      .map(({ message }) => serializeToBinary(message, this.options.accept))
+      .pausableBuffered(canSend$)
+      .combineLatest(connections$);
 
     outgoingMessages$
-      .subscribe((message) => this.sendMessage(message));
+      .subscribe(([binaryMessage, connection]) =>
+        connection.sendMessage(binaryMessage)
+      );
+  }
+
+  createConnection({ port, host, path }) {
+    return new WebSocketGremlinConnection({ port, host, path });
   }
 
   handleError(err) {
@@ -177,22 +199,6 @@ class GremlinClient extends EventEmitter {
     return message;
   };
 
-  sendMessage(message) {
-    let serializedMessage = this.options.accept + JSON.stringify(message);
-    serializedMessage = unescape(encodeURIComponent(serializedMessage));
-
-    // Let's start packing the message into binary
-    // mimeLength(1) + mimeType Length + serializedMessage Length
-    let binaryMessage = new Uint8Array(1 + serializedMessage.length);
-    binaryMessage[0] = this.options.accept.length;
-
-    for (let i = 0; i < serializedMessage.length; i++) {
-      binaryMessage[i + 1] = serializedMessage.charCodeAt(i);
-    }
-
-    this.connection.sendMessage(binaryMessage);
-  };
-
   /**
    * Asynchronously send a script to Gremlin Server for execution and fire
    * the provided callback when all results have been fetched.