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node_modules/websocket-extensions/CHANGELOG.md

@@ -0,0 +1,28 @@
+### 0.1.4 / 2020-06-02
+
+- Remove a ReDoS vulnerability in the header parser (CVE-2020-7662, reported by
+  Robert McLaughlin)
+- Change license from MIT to Apache 2.0
+
+### 0.1.3 / 2017-11-11
+
+- Accept extension names and parameters including uppercase letters
+- Handle extension names that clash with `Object.prototype` properties
+
+### 0.1.2 / 2017-09-10
+
+- Catch synchronous exceptions thrown when calling an extension
+- Fix race condition caused when a message is pushed after a cell has stopped
+  due to an error
+- Fix failure of `close()` to return if a message that's queued after one that
+  produces an error never finishes being processed
+
+### 0.1.1 / 2015-02-19
+
+- Prevent sessions being closed before they have finished processing messages
+- Add a callback to `Extensions.close()` so the caller can tell when it's safe
+  to close the socket
+
+### 0.1.0 / 2014-12-12
+
+- Initial release

node_modules/websocket-extensions/LICENSE.md

@@ -0,0 +1,12 @@
+Copyright 2014-2020 James Coglan
+
+Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+this file except in compliance with the License. You may obtain a copy of the
+License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software distributed
+under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+CONDITIONS OF ANY KIND, either express or implied. See the License for the
+specific language governing permissions and limitations under the License.

node_modules/websocket-extensions/README.md

@@ -0,0 +1,331 @@
+# websocket-extensions [![Build status](https://secure.travis-ci.org/faye/websocket-extensions-node.svg)](http://travis-ci.org/faye/websocket-extensions-node)
+
+A minimal framework that supports the implementation of WebSocket extensions in
+a way that's decoupled from the main protocol. This library aims to allow a
+WebSocket extension to be written and used with any protocol library, by
+defining abstract representations of frames and messages that allow modules to
+co-operate.
+
+`websocket-extensions` provides a container for registering extension plugins,
+and provides all the functions required to negotiate which extensions to use
+during a session via the `Sec-WebSocket-Extensions` header. By implementing the
+APIs defined in this document, an extension may be used by any WebSocket library
+based on this framework.
+
+## Installation
+
+```
+$ npm install websocket-extensions
+```
+
+## Usage
+
+There are two main audiences for this library: authors implementing the
+WebSocket protocol, and authors implementing extensions. End users of a
+WebSocket library or an extension should be able to use any extension by passing
+it as an argument to their chosen protocol library, without needing to know how
+either of them work, or how the `websocket-extensions` framework operates.
+
+The library is designed with the aim that any protocol implementation and any
+extension can be used together, so long as they support the same abstract
+representation of frames and messages.
+
+### Data types
+
+The APIs provided by the framework rely on two data types; extensions will
+expect to be given data and to be able to return data in these formats:
+
+#### *Frame*
+
+*Frame* is a structure representing a single WebSocket frame of any type. Frames
+are simple objects that must have at least the following properties, which
+represent the data encoded in the frame:
+
+| property     | description                                                        |
+| ------------ | ------------------------------------------------------------------ |
+| `final`      | `true` if the `FIN` bit is set, `false` otherwise                  |
+| `rsv1`       | `true` if the `RSV1` bit is set, `false` otherwise                 |
+| `rsv2`       | `true` if the `RSV2` bit is set, `false` otherwise                 |
+| `rsv3`       | `true` if the `RSV3` bit is set, `false` otherwise                 |
+| `opcode`     | the numeric opcode (`0`, `1`, `2`, `8`, `9`, or `10`) of the frame |
+| `masked`     | `true` if the `MASK` bit is set, `false` otherwise                 |
+| `maskingKey` | a 4-byte `Buffer` if `masked` is `true`, otherwise `null`          |
+| `payload`    | a `Buffer` containing the (unmasked) application data              |
+
+#### *Message*
+
+A *Message* represents a complete application message, which can be formed from
+text, binary and continuation frames. It has the following properties:
+
+| property | description                                                       |
+| -------- | ----------------------------------------------------------------- |
+| `rsv1`   | `true` if the first frame of the message has the `RSV1` bit set   |
+| `rsv2`   | `true` if the first frame of the message has the `RSV2` bit set   |
+| `rsv3`   | `true` if the first frame of the message has the `RSV3` bit set   |
+| `opcode` | the numeric opcode (`1` or `2`) of the first frame of the message |
+| `data`   | the concatenation of all the frame payloads in the message        |
+
+### For driver authors
+
+A driver author is someone implementing the WebSocket protocol proper, and who
+wishes end users to be able to use WebSocket extensions with their library.
+
+At the start of a WebSocket session, on both the client and the server side,
+they should begin by creating an extension container and adding whichever
+extensions they want to use.
+
+```js
+var Extensions = require('websocket-extensions'),
+    deflate    = require('permessage-deflate');
+
+var exts = new Extensions();
+exts.add(deflate);
+```
+
+In the following examples, `exts` refers to this `Extensions` instance.
+
+#### Client sessions
+
+Clients will use the methods `generateOffer()` and `activate(header)`.
+
+As part of the handshake process, the client must send a
+`Sec-WebSocket-Extensions` header to advertise that it supports the registered
+extensions. This header should be generated using:
+
+```js
+request.headers['sec-websocket-extensions'] = exts.generateOffer();
+```
+
+This returns a string, for example `"permessage-deflate;
+client_max_window_bits"`, that represents all the extensions the client is
+offering to use, and their parameters. This string may contain multiple offers
+for the same extension.
+
+When the client receives the handshake response from the server, it should pass
+the incoming `Sec-WebSocket-Extensions` header in to `exts` to activate the
+extensions the server has accepted:
+
+```js
+exts.activate(response.headers['sec-websocket-extensions']);
+```
+
+If the server has sent any extension responses that the client does not
+recognize, or are in conflict with one another for use of RSV bits, or that use
+invalid parameters for the named extensions, then `exts.activate()` will
+`throw`. In this event, the client driver should fail the connection with
+closing code `1010`.
+
+#### Server sessions
+
+Servers will use the method `generateResponse(header)`.
+
+A server session needs to generate a `Sec-WebSocket-Extensions` header to send
+in its handshake response:
+
+```js
+var clientOffer = request.headers['sec-websocket-extensions'],
+    extResponse = exts.generateResponse(clientOffer);
+
+response.headers['sec-websocket-extensions'] = extResponse;
+```
+
+Calling `exts.generateResponse(header)` activates those extensions the client
+has asked to use, if they are registered, asks each extension for a set of
+response parameters, and returns a string containing the response parameters for
+all accepted extensions.
+
+#### In both directions
+
+Both clients and servers will use the methods `validFrameRsv(frame)`,
+`processIncomingMessage(message)` and `processOutgoingMessage(message)`.
+
+The WebSocket protocol requires that frames do not have any of the `RSV` bits
+set unless there is an extension in use that allows otherwise. When processing
+an incoming frame, sessions should pass a *Frame* object to:
+
+```js
+exts.validFrameRsv(frame)
+```
+
+If this method returns `false`, the session should fail the WebSocket connection
+with closing code `1002`.
+
+To pass incoming messages through the extension stack, a session should
+construct a *Message* object according to the above datatype definitions, and
+call:
+
+```js
+exts.processIncomingMessage(message, function(error, msg) {
+  // hand the message off to the application
+});
+```
+
+If any extensions fail to process the message, then the callback will yield an
+error and the session should fail the WebSocket connection with closing code
+`1010`. If `error` is `null`, then `msg` should be passed on to the application.
+
+To pass outgoing messages through the extension stack, a session should
+construct a *Message* as before, and call:
+
+```js
+exts.processOutgoingMessage(message, function(error, msg) {
+  // write message to the transport
+});
+```
+
+If any extensions fail to process the message, then the callback will yield an
+error and the session should fail the WebSocket connection with closing code
+`1010`. If `error` is `null`, then `message` should be converted into frames
+(with the message's `rsv1`, `rsv2`, `rsv3` and `opcode` set on the first frame)
+and written to the transport.
+
+At the end of the WebSocket session (either when the protocol is explicitly
+ended or the transport connection disconnects), the driver should call:
+
+```js
+exts.close(function() {})
+```
+
+The callback is invoked when all extensions have finished processing any
+messages in the pipeline and it's safe to close the socket.
+
+### For extension authors
+
+An extension author is someone implementing an extension that transforms
+WebSocket messages passing between the client and server. They would like to
+implement their extension once and have it work with any protocol library.
+
+Extension authors will not install `websocket-extensions` or call it directly.
+Instead, they should implement the following API to allow their extension to
+plug into the `websocket-extensions` framework.
+
+An `Extension` is any object that has the following properties:
+
+| property | description                                                                  |
+| -------- | ---------------------------------------------------------------------------- |
+| `name`   | a string containing the name of the extension as used in negotiation headers |
+| `type`   | a string, must be `"permessage"`                                             |
+| `rsv1`   | either `true` if the extension uses the RSV1 bit, `false` otherwise          |
+| `rsv2`   | either `true` if the extension uses the RSV2 bit, `false` otherwise          |
+| `rsv3`   | either `true` if the extension uses the RSV3 bit, `false` otherwise          |
+
+It must also implement the following methods:
+
+```js
+ext.createClientSession()
+```
+
+This returns a *ClientSession*, whose interface is defined below.
+
+```js
+ext.createServerSession(offers)
+```
+
+This takes an array of offer params and returns a *ServerSession*, whose
+interface is defined below. For example, if the client handshake contains the
+offer header:
+
+```
+Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover; server_max_window_bits=8, \
+                          permessage-deflate; server_max_window_bits=15
+```
+
+then the `permessage-deflate` extension will receive the call:
+
+```js
+ext.createServerSession([
+  { server_no_context_takeover: true, server_max_window_bits: 8 },
+  { server_max_window_bits: 15 }
+]);
+```
+
+The extension must decide which set of parameters it wants to accept, if any,
+and return a *ServerSession* if it wants to accept the parameters and `null`
+otherwise.
+
+#### *ClientSession*
+
+A *ClientSession* is the type returned by `ext.createClientSession()`. It must
+implement the following methods, as well as the *Session* API listed below.
+
+```js
+clientSession.generateOffer()
+// e.g.  -> [
+//            { server_no_context_takeover: true, server_max_window_bits: 8 },
+//            { server_max_window_bits: 15 }
+//          ]
+```
+
+This must return a set of parameters to include in the client's
+`Sec-WebSocket-Extensions` offer header. If the session wants to offer multiple
+configurations, it can return an array of sets of parameters as shown above.
+
+```js
+clientSession.activate(params) // -> true
+```
+
+This must take a single set of parameters from the server's handshake response
+and use them to configure the client session. If the client accepts the given
+parameters, then this method must return `true`. If it returns any other value,
+the framework will interpret this as the client rejecting the response, and will
+`throw`.
+
+#### *ServerSession*
+
+A *ServerSession* is the type returned by `ext.createServerSession(offers)`. It
+must implement the following methods, as well as the *Session* API listed below.
+
+```js
+serverSession.generateResponse()
+// e.g.  -> { server_max_window_bits: 8 }
+```
+
+This returns the set of parameters the server session wants to send in its
+`Sec-WebSocket-Extensions` response header. Only one set of parameters is
+returned to the client per extension. Server sessions that would confict on
+their use of RSV bits are not activated.
+
+#### *Session*
+
+The *Session* API must be implemented by both client and server sessions. It
+contains two methods, `processIncomingMessage(message)` and
+`processOutgoingMessage(message)`.
+
+```js
+session.processIncomingMessage(message, function(error, msg) { ... })
+```
+
+The session must implement this method to take an incoming *Message* as defined
+above, transform it in any way it needs, then return it via the callback. If
+there is an error processing the message, this method should yield an error as
+the first argument.
+
+```js
+session.processOutgoingMessage(message, function(error, msg) { ... })
+```
+
+The session must implement this method to take an outgoing *Message* as defined
+above, transform it in any way it needs, then return it via the callback. If
+there is an error processing the message, this method should yield an error as
+the first argument.
+
+Note that both `processIncomingMessage()` and `processOutgoingMessage()` can
+perform their logic asynchronously, are allowed to process multiple messages
+concurrently, and are not required to complete working on messages in the same
+order the messages arrive. `websocket-extensions` will reorder messages as your
+extension emits them and will make sure every extension is given messages in the
+order they arrive from the driver. This allows extensions to maintain state that
+depends on the messages' wire order, for example keeping a DEFLATE compression
+context between messages.
+
+```js
+session.close()
+```
+
+The framework will call this method when the WebSocket session ends, allowing
+the session to release any resources it's using.
+
+## Examples
+
+- Consumer: [websocket-driver](https://github.com/faye/websocket-driver-node)
+- Provider: [permessage-deflate](https://github.com/faye/permessage-deflate-node)

node_modules/websocket-extensions/lib/parser.js

@@ -0,0 +1,103 @@
+'use strict';
+
+var TOKEN    = /([!#\$%&'\*\+\-\.\^_`\|~0-9A-Za-z]+)/,
+    NOTOKEN  = /([^!#\$%&'\*\+\-\.\^_`\|~0-9A-Za-z])/g,
+    QUOTED   = /"((?:\\[\x00-\x7f]|[^\x00-\x08\x0a-\x1f\x7f"\\])*)"/,
+    PARAM    = new RegExp(TOKEN.source + '(?:=(?:' + TOKEN.source + '|' + QUOTED.source + '))?'),
+    EXT      = new RegExp(TOKEN.source + '(?: *; *' + PARAM.source + ')*', 'g'),
+    EXT_LIST = new RegExp('^' + EXT.source + '(?: *, *' + EXT.source + ')*$'),
+    NUMBER   = /^-?(0|[1-9][0-9]*)(\.[0-9]+)?$/;
+
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+
+var Parser = {
+  parseHeader: function(header) {
+    var offers = new Offers();
+    if (header === '' || header === undefined) return offers;
+
+    if (!EXT_LIST.test(header))
+      throw new SyntaxError('Invalid Sec-WebSocket-Extensions header: ' + header);
+
+    var values = header.match(EXT);
+
+    values.forEach(function(value) {
+      var params = value.match(new RegExp(PARAM.source, 'g')),
+          name   = params.shift(),
+          offer  = {};
+
+      params.forEach(function(param) {
+        var args = param.match(PARAM), key = args[1], data;
+
+        if (args[2] !== undefined) {
+          data = args[2];
+        } else if (args[3] !== undefined) {
+          data = args[3].replace(/\\/g, '');
+        } else {
+          data = true;
+        }
+        if (NUMBER.test(data)) data = parseFloat(data);
+
+        if (hasOwnProperty.call(offer, key)) {
+          offer[key] = [].concat(offer[key]);
+          offer[key].push(data);
+        } else {
+          offer[key] = data;
+        }
+      }, this);
+      offers.push(name, offer);
+    }, this);
+
+    return offers;
+  },
+
+  serializeParams: function(name, params) {
+    var values = [];
+
+    var print = function(key, value) {
+      if (value instanceof Array) {
+        value.forEach(function(v) { print(key, v) });
+      } else if (value === true) {
+        values.push(key);
+      } else if (typeof value === 'number') {
+        values.push(key + '=' + value);
+      } else if (NOTOKEN.test(value)) {
+        values.push(key + '="' + value.replace(/"/g, '\\"') + '"');
+      } else {
+        values.push(key + '=' + value);
+      }
+    };
+
+    for (var key in params) print(key, params[key]);
+
+    return [name].concat(values).join('; ');
+  }
+};
+
+var Offers = function() {
+  this._byName  = {};
+  this._inOrder = [];
+};
+
+Offers.prototype.push = function(name, params) {
+  if (!hasOwnProperty.call(this._byName, name))
+    this._byName[name] = [];
+
+  this._byName[name].push(params);
+  this._inOrder.push({ name: name, params: params });
+};
+
+Offers.prototype.eachOffer = function(callback, context) {
+  var list = this._inOrder;
+  for (var i = 0, n = list.length; i < n; i++)
+    callback.call(context, list[i].name, list[i].params);
+};
+
+Offers.prototype.byName = function(name) {
+  return this._byName[name] || [];
+};
+
+Offers.prototype.toArray = function() {
+  return this._inOrder.slice();
+};
+
+module.exports = Parser;

node_modules/websocket-extensions/lib/pipeline/cell.js

@@ -0,0 +1,53 @@
+'use strict';
+
+var Functor = require('./functor'),
+    Pledge  = require('./pledge');
+
+var Cell = function(tuple) {
+  this._ext     = tuple[0];
+  this._session = tuple[1];
+
+  this._functors = {
+    incoming: new Functor(this._session, 'processIncomingMessage'),
+    outgoing: new Functor(this._session, 'processOutgoingMessage')
+  };
+};
+
+Cell.prototype.pending = function(direction) {
+  var functor = this._functors[direction];
+  if (!functor._stopped) functor.pending += 1;
+};
+
+Cell.prototype.incoming = function(error, message, callback, context) {
+  this._exec('incoming', error, message, callback, context);
+};
+
+Cell.prototype.outgoing = function(error, message, callback, context) {
+  this._exec('outgoing', error, message, callback, context);
+};
+
+Cell.prototype.close = function() {
+  this._closed = this._closed || new Pledge();
+  this._doClose();
+  return this._closed;
+};
+
+Cell.prototype._exec = function(direction, error, message, callback, context) {
+  this._functors[direction].call(error, message, function(err, msg) {
+    if (err) err.message = this._ext.name + ': ' + err.message;
+    callback.call(context, err, msg);
+    this._doClose();
+  }, this);
+};
+
+Cell.prototype._doClose = function() {
+  var fin  = this._functors.incoming,
+      fout = this._functors.outgoing;
+
+  if (!this._closed || fin.pending + fout.pending !== 0) return;
+  if (this._session) this._session.close();
+  this._session = null;
+  this._closed.done();
+};
+
+module.exports = Cell;

node_modules/websocket-extensions/lib/pipeline/functor.js

@@ -0,0 +1,72 @@
+'use strict';
+
+var RingBuffer = require('./ring_buffer');
+
+var Functor = function(session, method) {
+  this._session = session;
+  this._method  = method;
+  this._queue   = new RingBuffer(Functor.QUEUE_SIZE);
+  this._stopped = false;
+  this.pending  = 0;
+};
+
+Functor.QUEUE_SIZE = 8;
+
+Functor.prototype.call = function(error, message, callback, context) {
+  if (this._stopped) return;
+
+  var record = { error: error, message: message, callback: callback, context: context, done: false },
+      called = false,
+      self   = this;
+
+  this._queue.push(record);
+
+  if (record.error) {
+    record.done = true;
+    this._stop();
+    return this._flushQueue();
+  }
+
+  var handler = function(err, msg) {
+    if (!(called ^ (called = true))) return;
+
+    if (err) {
+      self._stop();
+      record.error   = err;
+      record.message = null;
+    } else {
+      record.message = msg;
+    }
+
+    record.done = true;
+    self._flushQueue();
+  };
+
+  try {
+    this._session[this._method](message, handler);
+  } catch (err) {
+    handler(err);
+  }
+};
+
+Functor.prototype._stop = function() {
+  this.pending  = this._queue.length;
+  this._stopped = true;
+};
+
+Functor.prototype._flushQueue = function() {
+  var queue = this._queue, record;
+
+  while (queue.length > 0 && queue.peek().done) {
+    record = queue.shift();
+    if (record.error) {
+      this.pending = 0;
+      queue.clear();
+    } else {
+      this.pending -= 1;
+    }
+    record.callback.call(record.context, record.error, record.message);
+  }
+};
+
+module.exports = Functor;

node_modules/websocket-extensions/lib/pipeline/index.js

@@ -0,0 +1,47 @@
+'use strict';
+
+var Cell   = require('./cell'),
+    Pledge = require('./pledge');
+
+var Pipeline = function(sessions) {
+  this._cells   = sessions.map(function(session) { return new Cell(session) });
+  this._stopped = { incoming: false, outgoing: false };
+};
+
+Pipeline.prototype.processIncomingMessage = function(message, callback, context) {
+  if (this._stopped.incoming) return;
+  this._loop('incoming', this._cells.length - 1, -1, -1, message, callback, context);
+};
+
+Pipeline.prototype.processOutgoingMessage = function(message, callback, context) {
+  if (this._stopped.outgoing) return;
+  this._loop('outgoing', 0, this._cells.length, 1, message, callback, context);
+};
+
+Pipeline.prototype.close = function(callback, context) {
+  this._stopped = { incoming: true, outgoing: true };
+
+  var closed = this._cells.map(function(a) { return a.close() });
+  if (callback)
+    Pledge.all(closed).then(function() { callback.call(context) });
+};
+
+Pipeline.prototype._loop = function(direction, start, end, step, message, callback, context) {
+  var cells = this._cells,
+      n     = cells.length,
+      self  = this;
+
+  while (n--) cells[n].pending(direction);
+
+  var pipe = function(index, error, msg) {
+    if (index === end) return callback.call(context, error, msg);
+
+    cells[index][direction](error, msg, function(err, m) {
+      if (err) self._stopped[direction] = true;
+      pipe(index + step, err, m);
+    });
+  };
+  pipe(start, null, message);
+};
+
+module.exports = Pipeline;

node_modules/websocket-extensions/lib/pipeline/pledge.js

@@ -0,0 +1,37 @@
+'use strict';
+
+var RingBuffer = require('./ring_buffer');
+
+var Pledge = function() {
+  this._complete  = false;
+  this._callbacks = new RingBuffer(Pledge.QUEUE_SIZE);
+};
+
+Pledge.QUEUE_SIZE = 4;
+
+Pledge.all = function(list) {
+  var pledge  = new Pledge(),
+      pending = list.length,
+      n       = pending;
+
+  if (pending === 0) pledge.done();
+
+  while (n--) list[n].then(function() {
+    pending -= 1;
+    if (pending === 0) pledge.done();
+  });
+  return pledge;
+};
+
+Pledge.prototype.then = function(callback) {
+  if (this._complete) callback();
+  else this._callbacks.push(callback);
+};
+
+Pledge.prototype.done = function() {
+  this._complete = true;
+  var callbacks = this._callbacks, callback;
+  while (callback = callbacks.shift()) callback();
+};
+
+module.exports = Pledge;

node_modules/websocket-extensions/lib/pipeline/ring_buffer.js

@@ -0,0 +1,66 @@
+'use strict';
+
+var RingBuffer = function(bufferSize) {
+  this._bufferSize = bufferSize;
+  this.clear();
+};
+
+RingBuffer.prototype.clear = function() {
+  this._buffer     = new Array(this._bufferSize);
+  this._ringOffset = 0;
+  this._ringSize   = this._bufferSize;
+  this._head       = 0;
+  this._tail       = 0;
+  this.length      = 0;
+};
+
+RingBuffer.prototype.push = function(value) {
+  var expandBuffer = false,
+      expandRing   = false;
+
+  if (this._ringSize < this._bufferSize) {
+    expandBuffer = (this._tail === 0);
+  } else if (this._ringOffset === this._ringSize) {
+    expandBuffer = true;
+    expandRing   = (this._tail === 0);
+  }
+
+  if (expandBuffer) {
+    this._tail       = this._bufferSize;
+    this._buffer     = this._buffer.concat(new Array(this._bufferSize));
+    this._bufferSize = this._buffer.length;
+
+    if (expandRing)
+      this._ringSize = this._bufferSize;
+  }
+
+  this._buffer[this._tail] = value;
+  this.length += 1;
+  if (this._tail < this._ringSize) this._ringOffset += 1;
+  this._tail = (this._tail + 1) % this._bufferSize;
+};
+
+RingBuffer.prototype.peek = function() {
+  if (this.length === 0) return void 0;
+  return this._buffer[this._head];
+};
+
+RingBuffer.prototype.shift = function() {
+  if (this.length === 0) return void 0;
+
+  var value = this._buffer[this._head];
+  this._buffer[this._head] = void 0;
+  this.length -= 1;
+  this._ringOffset -= 1;
+
+  if (this._ringOffset === 0 && this.length > 0) {
+    this._head       = this._ringSize;
+    this._ringOffset = this.length;
+    this._ringSize   = this._bufferSize;
+  } else {
+    this._head = (this._head + 1) % this._ringSize;
+  }
+  return value;
+};
+
+module.exports = RingBuffer;

node_modules/websocket-extensions/lib/websocket_extensions.js

@@ -0,0 +1,162 @@
+'use strict';
+
+var Parser   = require('./parser'),
+    Pipeline = require('./pipeline');
+
+var Extensions = function() {
+  this._rsv1 = this._rsv2 = this._rsv3 = null;
+
+  this._byName   = {};
+  this._inOrder  = [];
+  this._sessions = [];
+  this._index    = {};
+};
+
+Extensions.MESSAGE_OPCODES = [1, 2];
+
+var instance = {
+  add: function(ext) {
+    if (typeof ext.name !== 'string') throw new TypeError('extension.name must be a string');
+    if (ext.type !== 'permessage') throw new TypeError('extension.type must be "permessage"');
+
+    if (typeof ext.rsv1 !== 'boolean') throw new TypeError('extension.rsv1 must be true or false');
+    if (typeof ext.rsv2 !== 'boolean') throw new TypeError('extension.rsv2 must be true or false');
+    if (typeof ext.rsv3 !== 'boolean') throw new TypeError('extension.rsv3 must be true or false');
+
+    if (this._byName.hasOwnProperty(ext.name))
+      throw new TypeError('An extension with name "' + ext.name + '" is already registered');
+
+    this._byName[ext.name] = ext;
+    this._inOrder.push(ext);
+  },
+
+  generateOffer: function() {
+    var sessions = [],
+        offer    = [],
+        index    = {};
+
+    this._inOrder.forEach(function(ext) {
+      var session = ext.createClientSession();
+      if (!session) return;
+
+      var record = [ext, session];
+      sessions.push(record);
+      index[ext.name] = record;
+
+      var offers = session.generateOffer();
+      offers = offers ? [].concat(offers) : [];
+
+      offers.forEach(function(off) {
+        offer.push(Parser.serializeParams(ext.name, off));
+      }, this);
+    }, this);
+
+    this._sessions = sessions;
+    this._index    = index;
+
+    return offer.length > 0 ? offer.join(', ') : null;
+  },
+
+  activate: function(header) {
+    var responses = Parser.parseHeader(header),
+        sessions  = [];
+
+    responses.eachOffer(function(name, params) {
+      var record = this._index[name];
+
+      if (!record)
+        throw new Error('Server sent an extension response for unknown extension "' + name + '"');
+
+      var ext      = record[0],
+          session  = record[1],
+          reserved = this._reserved(ext);
+
+      if (reserved)
+        throw new Error('Server sent two extension responses that use the RSV' +
+                        reserved[0] + ' bit: "' +
+                        reserved[1] + '" and "' + ext.name + '"');
+
+      if (session.activate(params) !== true)
+        throw new Error('Server sent unacceptable extension parameters: ' +
+                        Parser.serializeParams(name, params));
+
+      this._reserve(ext);
+      sessions.push(record);
+    }, this);
+
+    this._sessions = sessions;
+    this._pipeline = new Pipeline(sessions);
+  },
+
+  generateResponse: function(header) {
+    var sessions = [],
+        response = [],
+        offers   = Parser.parseHeader(header);
+
+    this._inOrder.forEach(function(ext) {
+      var offer = offers.byName(ext.name);
+      if (offer.length === 0 || this._reserved(ext)) return;
+
+      var session = ext.createServerSession(offer);
+      if (!session) return;
+
+      this._reserve(ext);
+      sessions.push([ext, session]);
+      response.push(Parser.serializeParams(ext.name, session.generateResponse()));
+    }, this);
+
+    this._sessions = sessions;
+    this._pipeline = new Pipeline(sessions);
+
+    return response.length > 0 ? response.join(', ') : null;
+  },
+
+  validFrameRsv: function(frame) {
+    var allowed = { rsv1: false, rsv2: false, rsv3: false },
+        ext;
+
+    if (Extensions.MESSAGE_OPCODES.indexOf(frame.opcode) >= 0) {
+      for (var i = 0, n = this._sessions.length; i < n; i++) {
+        ext = this._sessions[i][0];
+        allowed.rsv1 = allowed.rsv1 || ext.rsv1;
+        allowed.rsv2 = allowed.rsv2 || ext.rsv2;
+        allowed.rsv3 = allowed.rsv3 || ext.rsv3;
+      }
+    }
+
+    return (allowed.rsv1 || !frame.rsv1) &&
+           (allowed.rsv2 || !frame.rsv2) &&
+           (allowed.rsv3 || !frame.rsv3);
+  },
+
+  processIncomingMessage: function(message, callback, context) {
+    this._pipeline.processIncomingMessage(message, callback, context);
+  },
+
+  processOutgoingMessage: function(message, callback, context) {
+    this._pipeline.processOutgoingMessage(message, callback, context);
+  },
+
+  close: function(callback, context) {
+    if (!this._pipeline) return callback.call(context);
+    this._pipeline.close(callback, context);
+  },
+
+  _reserve: function(ext) {
+    this._rsv1 = this._rsv1 || (ext.rsv1 && ext.name);
+    this._rsv2 = this._rsv2 || (ext.rsv2 && ext.name);
+    this._rsv3 = this._rsv3 || (ext.rsv3 && ext.name);
+  },
+
+  _reserved: function(ext) {
+    if (this._rsv1 && ext.rsv1) return [1, this._rsv1];
+    if (this._rsv2 && ext.rsv2) return [2, this._rsv2];
+    if (this._rsv3 && ext.rsv3) return [3, this._rsv3];
+    return false;
+  }
+};
+
+for (var key in instance)
+  Extensions.prototype[key] = instance[key];
+
+module.exports = Extensions;

node_modules/websocket-extensions/package.json

@@ -0,0 +1,29 @@
+{
+          "name": "websocket-extensions",
+          "description": "Generic extension manager for WebSocket connections",
+          "homepage": "http://github.com/faye/websocket-extensions-node",
+          "author": "James Coglan <jcoglan@gmail.com> (http://jcoglan.com/)",
+          "keywords": [
+                    "websocket"
+          ],
+          "license": "Apache-2.0",
+          "version": "0.1.4",
+          "engines": {
+                    "node": ">=0.8.0"
+          },
+          "files": [
+                    "lib"
+          ],
+          "main": "./lib/websocket_extensions",
+          "devDependencies": {
+                    "jstest": "*"
+          },
+          "scripts": {
+                    "test": "jstest spec/runner.js"
+          },
+          "repository": {
+                    "type": "git",
+                    "url": "git://github.com/faye/websocket-extensions-node.git"
+          },
+          "bugs": "http://github.com/faye/websocket-extensions-node/issues"
+}