Add the hasBinary flag

docs/API.md

@@ -29,6 +29,7 @@
     - [Event: 'connection'](#event-connect)
     - [Flag: 'volatile'](#flag-volatile)
     - [Flag: 'local'](#flag-local)
+    - [Flag: 'hasBinary'](#flag-hasbinary)
   - [Class: Socket](#socket)
     - [socket.id](#socketid)
     - [socket.rooms](#socketrooms)
@@ -47,6 +48,7 @@
     - [socket.disconnect(close)](#socketdisconnectclose)
     - [Flag: 'broadcast'](#flag-broadcast)
     - [Flag: 'volatile'](#flag-volatile-1)
+    - [Flag: 'hasBinary'](#flag-hasbinary-1)
     - [Event: 'disconnect'](#event-disconnect)
     - [Event: 'error'](#event-error)
     - [Event: 'disconnecting'](#event-disconnecting)
@@ -327,6 +329,14 @@ Sets a modifier for a subsequent event emission that the event data may be lost
 io.volatile.emit('an event', { some: 'data' }); // the clients may or may not receive it
 ```
 
+#### Flag: 'hasBinary'
+
+Specifies whether there is binary data in the emitted data. Increases performance when specified. Can be `true` or `false`.
+
+```js
+io.hasBinary(false).emit('an event', { some: 'data' });
+```
+
 #### Flag: 'local'
 
 Sets a modifier for a subsequent event emission that the event data will only be _broadcast_ to the current node (when the [Redis adapter](https://github.com/socketio/socket.io-redis) is used).
@@ -545,6 +555,17 @@ io.on('connection', function(socket){
 });
 ```
 
+#### Flag: 'hasBinary'
+
+Specifies whether there is binary data in the emmited data. Increases performance when specified. Can be `true` or `false`.
+
+```js
+var io = require('socket.io')();
+io.on('connection', function(socket){
+  socket.hasBinary(false).emit('an event', { some: 'data' }); // The data to send has no binary data
+});
+```
+
 #### Event: 'disconnect'
 
   - `reason` _(String)_ the reason of the disconnection (either client or server-side)

docs/emit.md

@@ -37,6 +37,9 @@ function onConnect(socket){
   // sending a message that might be dropped if the client is not ready to receive messages
   socket.volatile.emit('maybe', 'do you really need it?');
 
+  // specifying whether the data to send has binary data
+  socket.hasBinary(false).emit('what', 'I have no binaries!');
+
   // sending to all clients on this node (when using multiple nodes)
   io.local.emit('hi', 'my lovely babies');
 

lib/namespace.js

@@ -210,8 +210,7 @@ Namespace.prototype.emit = function(ev){
   } else {
     // set up packet object
     var args = Array.prototype.slice.call(arguments);
-    var parserType = parser.EVENT; // default
-    if (hasBin(args)) { parserType = parser.BINARY_EVENT; } // binary
+    var parserType = (this.flags.hasBinary !== undefined ? this.flags.hasBinary : hasBin(args)) ? parser.BINARY_EVENT : parser.EVENT;
 
     var packet = { type: parserType, data: args };
 
@@ -272,3 +271,16 @@ Namespace.prototype.compress = function(compress){
   this.flags.compress = compress;
   return this;
 };
+
+/**
+ * Sets the hasBinary flag
+ *
+ * @param {Boolean} Encode as if it has binary data if `true`, Encode as if it doesnt have binary data if `false`
+ * @return {Socket} self
+ * @api public
+ */
+
+ Namespace.prototype.hasBinary = function (bool) {
+   this.flags.hasBinary = bool;
+   return this;
+ };

lib/socket.js

@@ -142,8 +142,9 @@ Socket.prototype.emit = function(ev){
     emit.apply(this, arguments);
   } else {
     var args = Array.prototype.slice.call(arguments);
+
     var packet = {
-      type: hasBin(args) ? parser.BINARY_EVENT : parser.EVENT,
+      type: (this.flags.hasBinary !== undefined ? this.flags.hasBinary : hasBin(args)) ? parser.BINARY_EVENT : parser.EVENT,
       data: args
     };
 
@@ -481,6 +482,19 @@ Socket.prototype.compress = function(compress){
   return this;
 };
 
+/**
+ * Sets the hasBinary flag
+ *
+ * @param {Boolean} Encode as if it has binary data if `true`, Encode as if it doesnt have binary data if `false`
+ * @return {Socket} self
+ * @api public
+ */
+
+ Socket.prototype.hasBinary = function (bool) {
+   this.flags.hasBinary = bool;
+   return this;
+ };
+
 /**
  * Dispatch incoming event to socket listeners.
  *