noname/node_modules/ws/lib/PerMessageDeflate.js

326 lines
8.8 KiB
JavaScript

var zlib = require('zlib');
var AVAILABLE_WINDOW_BITS = [8, 9, 10, 11, 12, 13, 14, 15];
var DEFAULT_WINDOW_BITS = 15;
var DEFAULT_MEM_LEVEL = 8;
PerMessageDeflate.extensionName = 'permessage-deflate';
/**
* Per-message Compression Extensions implementation
*/
function PerMessageDeflate(options, isServer) {
if (this instanceof PerMessageDeflate === false) {
throw new TypeError("Classes can't be function-called");
}
this._options = options || {};
this._isServer = !!isServer;
this._inflate = null;
this._deflate = null;
this.params = null;
}
/**
* Create extension parameters offer
*
* @api public
*/
PerMessageDeflate.prototype.offer = function() {
var params = {};
if (this._options.serverNoContextTakeover) {
params.server_no_context_takeover = true;
}
if (this._options.clientNoContextTakeover) {
params.client_no_context_takeover = true;
}
if (this._options.serverMaxWindowBits) {
params.server_max_window_bits = this._options.serverMaxWindowBits;
}
if (this._options.clientMaxWindowBits) {
params.client_max_window_bits = this._options.clientMaxWindowBits;
} else if (this._options.clientMaxWindowBits == null) {
params.client_max_window_bits = true;
}
return params;
};
/**
* Accept extension offer
*
* @api public
*/
PerMessageDeflate.prototype.accept = function(paramsList) {
paramsList = this.normalizeParams(paramsList);
var params;
if (this._isServer) {
params = this.acceptAsServer(paramsList);
} else {
params = this.acceptAsClient(paramsList);
}
this.params = params;
return params;
};
/**
* Releases all resources used by the extension
*
* @api public
*/
PerMessageDeflate.prototype.cleanup = function() {
if (this._inflate) {
if (this._inflate.writeInProgress) {
this._inflate.pendingClose = true;
} else {
if (this._inflate.close) this._inflate.close();
this._inflate = null;
}
}
if (this._deflate) {
if (this._deflate.writeInProgress) {
this._deflate.pendingClose = true;
} else {
if (this._deflate.close) this._deflate.close();
this._deflate = null;
}
}
};
/**
* Accept extension offer from client
*
* @api private
*/
PerMessageDeflate.prototype.acceptAsServer = function(paramsList) {
var accepted = {};
var result = paramsList.some(function(params) {
accepted = {};
if (this._options.serverNoContextTakeover === false && params.server_no_context_takeover) {
return;
}
if (this._options.serverMaxWindowBits === false && params.server_max_window_bits) {
return;
}
if (typeof this._options.serverMaxWindowBits === 'number' &&
typeof params.server_max_window_bits === 'number' &&
this._options.serverMaxWindowBits > params.server_max_window_bits) {
return;
}
if (typeof this._options.clientMaxWindowBits === 'number' && !params.client_max_window_bits) {
return;
}
if (this._options.serverNoContextTakeover || params.server_no_context_takeover) {
accepted.server_no_context_takeover = true;
}
if (this._options.clientNoContextTakeover) {
accepted.client_no_context_takeover = true;
}
if (this._options.clientNoContextTakeover !== false && params.client_no_context_takeover) {
accepted.client_no_context_takeover = true;
}
if (typeof this._options.serverMaxWindowBits === 'number') {
accepted.server_max_window_bits = this._options.serverMaxWindowBits;
} else if (typeof params.server_max_window_bits === 'number') {
accepted.server_max_window_bits = params.server_max_window_bits;
}
if (typeof this._options.clientMaxWindowBits === 'number') {
accepted.client_max_window_bits = this._options.clientMaxWindowBits;
} else if (this._options.clientMaxWindowBits !== false && typeof params.client_max_window_bits === 'number') {
accepted.client_max_window_bits = params.client_max_window_bits;
}
return true;
}, this);
if (!result) {
throw new Error('Doesn\'t support the offered configuration');
}
return accepted;
};
/**
* Accept extension response from server
*
* @api privaye
*/
PerMessageDeflate.prototype.acceptAsClient = function(paramsList) {
var params = paramsList[0];
if (this._options.clientNoContextTakeover != null) {
if (this._options.clientNoContextTakeover === false && params.client_no_context_takeover) {
throw new Error('Invalid value for "client_no_context_takeover"');
}
}
if (this._options.clientMaxWindowBits != null) {
if (this._options.clientMaxWindowBits === false && params.client_max_window_bits) {
throw new Error('Invalid value for "client_max_window_bits"');
}
if (typeof this._options.clientMaxWindowBits === 'number' &&
(!params.client_max_window_bits || params.client_max_window_bits > this._options.clientMaxWindowBits)) {
throw new Error('Invalid value for "client_max_window_bits"');
}
}
return params;
};
/**
* Normalize extensions parameters
*
* @api private
*/
PerMessageDeflate.prototype.normalizeParams = function(paramsList) {
return paramsList.map(function(params) {
Object.keys(params).forEach(function(key) {
var value = params[key];
if (value.length > 1) {
throw new Error('Multiple extension parameters for ' + key);
}
value = value[0];
switch (key) {
case 'server_no_context_takeover':
case 'client_no_context_takeover':
if (value !== true) {
throw new Error('invalid extension parameter value for ' + key + ' (' + value + ')');
}
params[key] = true;
break;
case 'server_max_window_bits':
case 'client_max_window_bits':
if (typeof value === 'string') {
value = parseInt(value, 10);
if (!~AVAILABLE_WINDOW_BITS.indexOf(value)) {
throw new Error('invalid extension parameter value for ' + key + ' (' + value + ')');
}
}
if (!this._isServer && value === true) {
throw new Error('Missing extension parameter value for ' + key);
}
params[key] = value;
break;
default:
throw new Error('Not defined extension parameter (' + key + ')');
}
}, this);
return params;
}, this);
};
/**
* Decompress message
*
* @api public
*/
PerMessageDeflate.prototype.decompress = function (data, fin, callback) {
var endpoint = this._isServer ? 'client' : 'server';
if (!this._inflate) {
var maxWindowBits = this.params[endpoint + '_max_window_bits'];
this._inflate = zlib.createInflateRaw({
windowBits: 'number' === typeof maxWindowBits ? maxWindowBits : DEFAULT_WINDOW_BITS
});
}
this._inflate.writeInProgress = true;
var self = this;
var buffers = [];
this._inflate.on('error', onError).on('data', onData);
this._inflate.write(data);
if (fin) {
this._inflate.write(new Buffer([0x00, 0x00, 0xff, 0xff]));
}
this._inflate.flush(function() {
cleanup();
callback(null, Buffer.concat(buffers));
});
function onError(err) {
cleanup();
callback(err);
}
function onData(data) {
buffers.push(data);
}
function cleanup() {
if (!self._inflate) return;
self._inflate.removeListener('error', onError);
self._inflate.removeListener('data', onData);
self._inflate.writeInProgress = false;
if ((fin && self.params[endpoint + '_no_context_takeover']) || self._inflate.pendingClose) {
if (self._inflate.close) self._inflate.close();
self._inflate = null;
}
}
};
/**
* Compress message
*
* @api public
*/
PerMessageDeflate.prototype.compress = function (data, fin, callback) {
var endpoint = this._isServer ? 'server' : 'client';
if (!this._deflate) {
var maxWindowBits = this.params[endpoint + '_max_window_bits'];
this._deflate = zlib.createDeflateRaw({
flush: zlib.Z_SYNC_FLUSH,
windowBits: 'number' === typeof maxWindowBits ? maxWindowBits : DEFAULT_WINDOW_BITS,
memLevel: this._options.memLevel || DEFAULT_MEM_LEVEL
});
}
this._deflate.writeInProgress = true;
var self = this;
var buffers = [];
this._deflate.on('error', onError).on('data', onData);
this._deflate.write(data);
this._deflate.flush(function() {
cleanup();
var data = Buffer.concat(buffers);
if (fin) {
data = data.slice(0, data.length - 4);
}
callback(null, data);
});
function onError(err) {
cleanup();
callback(err);
}
function onData(data) {
buffers.push(data);
}
function cleanup() {
if (!self._deflate) return;
self._deflate.removeListener('error', onError);
self._deflate.removeListener('data', onData);
self._deflate.writeInProgress = false;
if ((fin && self.params[endpoint + '_no_context_takeover']) || self._deflate.pendingClose) {
if (self._deflate.close) self._deflate.close();
self._deflate = null;
}
}
};
module.exports = PerMessageDeflate;