[fix]#16 added DDP 'failed' connection event as specs

README.md

@@ -40,6 +40,9 @@ const ddp = new DDP(options);
 ddp.on("connected", () => {
     console.log("Connected");
 });
+ddp.on("failed"), (version) => {
+   console.log("Connection failed: protocol version supported from " + version) 
+});
 
 const subId = ddp.sub("mySubscription");
 ddp.on("ready", message => {
@@ -100,6 +103,8 @@ Available options are:
   library.  On the server you can use whichever library implements the
   websocket protocol (e.g.  faye-websocket).
 
+- `version` **string** *optional* [default: `"1"`]: the proposed protocol version
+
 - `autoConnect` **boolean** *optional* [default: `true`]: whether to establish
   the connection to the server upon instantiation. When `false`, one can
   manually establish the connection with the `connect` method.

src/ddp.js

@@ -3,7 +3,7 @@ import Queue from "./queue";
 import Socket from "./socket";
 import {contains, uniqueId} from "./utils";
 
-const DDP_VERSION = "1";
+const DDP_VERSION_DEFAULT = "1";
 const PUBLIC_EVENTS = [
     // Subscription messages
     "ready", "nosub", "added", "changed", "removed",
@@ -30,6 +30,7 @@ export default class DDP extends EventEmitter {
         this.autoConnect = (options.autoConnect !== false);
         this.autoReconnect = (options.autoReconnect !== false);
         this.reconnectInterval = options.reconnectInterval || DEFAULT_RECONNECT_INTERVAL;
+        this.version = options.version || DDP_VERSION_DEFAULT;
 
         this.messageQueue = new Queue(message => {
             if (this.status === "connected") {
@@ -47,8 +48,8 @@ export default class DDP extends EventEmitter {
             // to establish the DDP connection
             this.socket.send({
                 msg: "connect",
-                version: DDP_VERSION,
-                support: [DDP_VERSION]
+                version: this.version,
+                support: [this.version]
             });
         });
 
@@ -70,6 +71,11 @@ export default class DDP extends EventEmitter {
                 this.status = "connected";
                 this.messageQueue.process();
                 this.emit("connected");
+            } else if (message.msg === "failed") {
+                // Close the underlaying socket and emit a 'failed' message with the DDP version the server would rather speak
+                // (see https://github.com/meteor/meteor/blob/devel/packages/ddp/DDP.md#messages)
+                this.socket.close();
+                this.emit("failed", message.version);
             } else if (message.msg === "ping") {
                 // Reply with a `pong` message to prevent the server from
                 // closing the connection

test/unit/ddp.js

@@ -286,6 +286,31 @@ describe("`DDP` class", () => {
             });
         });
 
+        it("handle `failed` DDP messages", () => {
+            const ddp = new DDP(options);
+            ddp.emit = sinon.spy();
+            const message = {
+                id: "id",
+                msg: "failed",
+                version: "2"  //DDP Mock Server version
+            };
+            ddp.socket.emit("message:in", message);
+
+            expect(ddp.emit).to.have.been.calledWith("failed", message.version);
+        });
+
+        it("close socket on `failed` DDP messages", () => {
+            const ddp = new DDP(options);
+            ddp.socket.close = sinon.spy();
+            ddp.socket.emit("message:in", {
+                id: "id",
+                msg: "failed",
+                version: "2"
+            });
+
+            expect(ddp.socket.close).to.have.callCount(1);
+        });
+
         it("triggers `messageQueue` processing upon connection", () => {
             const ddp = new DDP(options);
             ddp.emit = sinon.spy();