Implemented draining and orderly close to polling.

lib/transports/polling.js

@@ -90,8 +90,14 @@ Polling.prototype.onPollRequest = function (req, res) {
     req.cleanup = cleanup;
     req.on('close', onClose);
 
-    this.buffer = false;
-    this.flush();
+    this.writable = true;
+    this.emit('drain');
+
+    // if we're still writable but had a pending close, trigger an empty send
+    if (this.writable && this.shouldClose) {
+      debug('triggering empty send to append close packet');
+      this.send([]);
+    }
   }
 };
 
@@ -162,41 +168,22 @@ Polling.prototype.onData = function (data) {
 };
 
 /**
- * Flushes buffers.
- *
- * @api private
- */
-
-Polling.prototype.flush = function () {
-  if (this.writeBuffer) {
-    this.write(parser.encodePayload(this.writeBuffer));
-    this.writeBuffer = null;
-    this.emit('drain');
-  }
-};
-
-/**
- * Writes a packet.
+ * Writes a packet payload.
  *
  * @param {Object} packet
- * @param {Function} called when the packet is dispatched
  * @api private
  */
 
-Polling.prototype.send = function (packet, fn) {
-  if (this.buffer) {
-    if (!this.writeBuffer) {
-      this.writeBuffer = [];
-    }
-
-    debug('poll buffering packet: type %s | data %s', packet.type, packet.data);
-    this.writeBuffer.push(packet);
-    if (fn) this.once('drain', fn);
-  } else {
-    debug('poll writing packet: type %s | data %s', packet.type, packet.data);
-    this.write(parser.encodePayload([packet]));
-    if (fn) fn();
+Polling.prototype.send = function (packets) {
+  debug('polling writing packets', JSON.stringify(packets));
+  if (this.shouldClose) {
+    debug('appending close packet to payload');
+    packets.push({ type: 'close' });
+    this.shouldClose();
+    this.shouldClose = null;
   }
+
+  this.write(parser.encodePayload(packets));
 };
 
 /**
@@ -209,7 +196,7 @@ Polling.prototype.send = function (packet, fn) {
 Polling.prototype.write = function (data) {
   this.doWrite(data);
   this.req.cleanup();
-  this.buffer = true;
+  this.writable = false;
 };
 
 /**
@@ -225,5 +212,11 @@ Polling.prototype.doClose = function (fn) {
     this.dataReq.abort();
   }
 
-  this.send({ type: 'close' }, fn);
+  if (this.writable) {
+    debug('polling transport is writable - closing right away');
+    this.send([{ type: 'close' }]);
+  } else {
+    debug('polling transport not writable - marking that we should close');
+    this.shouldClose = fn;
+  }
 };