[WIP] Begin implementing permessage-deflate.

examples/tcp_server.js

@@ -1,8 +1,10 @@
 var net       = require('net'),
-    websocket = require('../lib/websocket/driver');
+    websocket = require('../lib/websocket/driver'),
+    deflate   = require('../lib/websocket/extensions/per_message_deflate');
 
 var server = net.createServer(function(connection) {
   var driver = websocket.server();
+  driver.addExtension('permessage-deflate', deflate.create());
 
   driver.on('connect', function() {
     if (websocket.isWebSocket(driver)) driver.start();

lib/websocket/driver/base.js

@@ -6,13 +6,14 @@ var Emitter = require('events').EventEmitter,
 var Base = function(request, url, options) {
   Emitter.call(this);
 
-  this._request   = request;
-  this._options   = options || {};
-  this._maxLength = this._options.maxLength || this.MAX_LENGTH;
-  this.__headers  = new Headers();
-  this.__queue    = [];
-  this.readyState = 0;
-  this.url        = url;
+  this._request    = request;
+  this._options    = options || {};
+  this._extensions = {};
+  this._maxLength  = this._options.maxLength || this.MAX_LENGTH;
+  this.__headers   = new Headers();
+  this.__queue     = [];
+  this.readyState  = 0;
+  this.url         = url;
 
   this.io = new streams.IO(this);
   this.messages = new streams.Messages(this);
@@ -51,6 +52,10 @@ var instance = {
     });
   },
 
+  addExtension: function(name, extension) {
+    this._extensions[name] = extension;
+  },
+
   getState: function() {
     return this.STATES[this.readyState] || null;
   },
@@ -108,6 +113,9 @@ var instance = {
 for (var key in instance)
   Base.prototype[key] = instance[key];
 
+Base.parseHeader = function(header) {
+  return Headers.parseHeader(header);
+};
 
 Base.ConnectEvent = function() {};
 

lib/websocket/driver/headers.js

@@ -3,6 +3,22 @@ var Headers = function() {
   this._lines = [];
 };
 
+Headers.parseHeader = function(header) {
+  if (!header) return [];
+
+  return header.split(/\s*,\s*/).map(function(value) {
+    var parts  = value.split(/\s*;\s*/),
+        name   = parts.shift(),
+        params = {};
+
+    parts.forEach(function(part) {
+      var pair = part.split(/\s*=\s*/);
+      params[pair[0]] = pair[1] || true;
+    });
+    return {name: name, params: params};
+  });
+};
+
 Headers.prototype.ALLOWED_DUPLICATES = ['set-cookie', 'set-cookie2', 'warning', 'www-authenticate']
 
 Headers.prototype.set = function(name, value) {

lib/websocket/driver/http_parser.js

@@ -19,7 +19,7 @@ var HttpParser = function(type) {
   };
 
   this._parser.onHeaderValue = function(b, start, length) {
-    self.headers[current] = b.toString('utf8', start, start + length);
+    self.set(current, b.toString('utf8', start, start + length));
   };
 
   this._parser.onHeadersComplete = this._parser[HTTPParser.kOnHeadersComplete] = function(info) {
@@ -27,11 +27,11 @@ var HttpParser = function(type) {
     self.statusCode = info.statusCode;
     self.url        = info.url;
     
-    var headers = info.headers;
+    var headers = info.headers, name, values;
     if (!headers) return;
 
     for (var i = 0, n = headers.length; i < n; i += 2)
-      self.headers[headers[i].toLowerCase()] = headers[i+1];
+      self.set(headers[i].toLowerCase(), headers[i+1]);
   };
 
   this._parser.onMessageComplete = this._parser[HTTPParser.kOnMessageComplete] = function() {
@@ -63,6 +63,13 @@ HttpParser.METHODS = {
   24: 'PATCH'
 };
 
+HttpParser.prototype.set = function(name, value) {
+  var values = [];
+  if (this.headers.hasOwnProperty(name)) values.push(this.headers[name]);
+  values.push(value);
+  this.headers[name] = values.join(', ');
+};
+
 HttpParser.prototype.isComplete = function() {
   return this._complete;
 };

lib/websocket/driver/hybi.js

@@ -175,6 +175,7 @@ var instance = {
     if (!secKey) return '';
 
     var accept    = Hybi.generateAccept(secKey),
+        offers    = Base.parseHeader(this._request.headers['sec-websocket-extensions']),
         protos    = this._request.headers['sec-websocket-protocol'],
         supported = this._protocols,
         proto,
@@ -195,6 +196,20 @@ var instance = {
       }
     }
 
+    // TODO: implement a selection procedure for extensions
+    // see http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-17#section-5
+    var extensions = offers.map(function(offer) {
+      var ext = this._extensions[offer.name];
+      return ext && ext.createSession(offer.params);
+    }, this).filter(function(k) {
+      return k;
+    });
+
+    if (extensions.length > 0) {
+      extensions = extensions.map(function(e) { return e.responseHeader() });
+      headers.push('Sec-WebSocket-Extensions: ' + extensions.join(', '));
+    }
+
     return new Buffer(headers.concat(this.__headers.toString(), '').join('\r\n'), 'utf8');
   },
 

lib/websocket/driver/server.js

@@ -34,6 +34,7 @@ var instance = {
     this._delegate = Server.http(this, this._options);
     this._delegate.messages = this.messages;
     this._delegate.io = this.io;
+    this._delegate._extensions = this._extensions;
 
     this._delegate.on('open', function() { self._open() });
     this.EVENTS.forEach(function(event) {

lib/websocket/extensions/per_message_deflate.js

@@ -0,0 +1,22 @@
+var PerMessageDeflate = function() {
+  this.name = 'permessage-deflate';
+};
+
+PerMessageDeflate.create = function() {
+  return new this();
+};
+
+PerMessageDeflate.prototype.createSession = function(params) {
+  return new Session(this, params);
+};
+
+var Session = function(extension, params) {
+  this._ext    = extension;
+  this._params = params;
+};
+
+Session.prototype.responseHeader = function() {
+  return this._ext.name;
+};
+
+module.exports = PerMessageDeflate;