474 lines
11 KiB
JavaScript
474 lines
11 KiB
JavaScript
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/**
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* Module dependencies.
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*/
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var utf8 = require('./utf8');
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var hasBinary = require('has-binary2');
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var after = require('after');
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var keys = require('./keys');
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/**
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* Current protocol version.
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*/
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exports.protocol = 3;
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/**
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* Packet types.
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*/
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var packets = exports.packets = {
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open: 0 // non-ws
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, close: 1 // non-ws
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, ping: 2
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, pong: 3
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, message: 4
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, upgrade: 5
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, noop: 6
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};
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var packetslist = keys(packets);
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/**
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* Premade error packet.
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*/
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var err = { type: 'error', data: 'parser error' };
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const EMPTY_BUFFER = Buffer.concat([]);
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/**
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* Encodes a packet.
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*
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* <packet type id> [ <data> ]
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*
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* Example:
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*
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* 5hello world
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* 3
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* 4
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*
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* Binary is encoded in an identical principle
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*
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* @api private
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*/
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exports.encodePacket = function (packet, supportsBinary, utf8encode, callback) {
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if (typeof supportsBinary === 'function') {
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callback = supportsBinary;
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supportsBinary = null;
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}
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if (typeof utf8encode === 'function') {
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callback = utf8encode;
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utf8encode = null;
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}
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if (Buffer.isBuffer(packet.data)) {
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return encodeBuffer(packet, supportsBinary, callback);
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} else if (packet.data && (packet.data.buffer || packet.data) instanceof ArrayBuffer) {
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return encodeBuffer({ type: packet.type, data: arrayBufferToBuffer(packet.data) }, supportsBinary, callback);
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}
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// Sending data as a utf-8 string
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var encoded = packets[packet.type];
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// data fragment is optional
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if (undefined !== packet.data) {
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encoded += utf8encode ? utf8.encode(String(packet.data), { strict: false }) : String(packet.data);
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}
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return callback('' + encoded);
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};
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/**
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* Encode Buffer data
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*/
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function encodeBuffer(packet, supportsBinary, callback) {
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if (!supportsBinary) {
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return exports.encodeBase64Packet(packet, callback);
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}
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var data = packet.data;
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var typeBuffer = Buffer.allocUnsafe(1);
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typeBuffer[0] = packets[packet.type];
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return callback(Buffer.concat([typeBuffer, data]));
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}
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/**
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* Encodes a packet with binary data in a base64 string
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*
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* @param {Object} packet, has `type` and `data`
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* @return {String} base64 encoded message
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*/
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exports.encodeBase64Packet = function(packet, callback){
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var data = Buffer.isBuffer(packet.data) ? packet.data : arrayBufferToBuffer(packet.data);
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var message = 'b' + packets[packet.type];
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message += data.toString('base64');
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return callback(message);
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};
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/**
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* Decodes a packet. Data also available as an ArrayBuffer if requested.
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*
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* @return {Object} with `type` and `data` (if any)
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* @api private
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*/
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exports.decodePacket = function (data, binaryType, utf8decode) {
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if (data === undefined) {
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return err;
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}
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var type;
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// String data
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if (typeof data === 'string') {
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type = data.charAt(0);
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if (type === 'b') {
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return exports.decodeBase64Packet(data.substr(1), binaryType);
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}
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if (utf8decode) {
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data = tryDecode(data);
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if (data === false) {
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return err;
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}
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}
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if (Number(type) != type || !packetslist[type]) {
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return err;
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}
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if (data.length > 1) {
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return { type: packetslist[type], data: data.substring(1) };
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} else {
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return { type: packetslist[type] };
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}
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}
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// Binary data
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if (binaryType === 'arraybuffer') {
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// wrap Buffer/ArrayBuffer data into an Uint8Array
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var intArray = new Uint8Array(data);
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type = intArray[0];
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return { type: packetslist[type], data: intArray.buffer.slice(1) };
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}
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if (data instanceof ArrayBuffer) {
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data = arrayBufferToBuffer(data);
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}
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type = data[0];
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return { type: packetslist[type], data: data.slice(1) };
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};
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function tryDecode(data) {
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try {
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data = utf8.decode(data, { strict: false });
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} catch (e) {
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return false;
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}
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return data;
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}
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/**
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* Decodes a packet encoded in a base64 string.
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*
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* @param {String} base64 encoded message
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* @return {Object} with `type` and `data` (if any)
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*/
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exports.decodeBase64Packet = function(msg, binaryType) {
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var type = packetslist[msg.charAt(0)];
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var data = Buffer.from(msg.substr(1), 'base64');
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if (binaryType === 'arraybuffer') {
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var abv = new Uint8Array(data.length);
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for (var i = 0; i < abv.length; i++){
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abv[i] = data[i];
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}
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data = abv.buffer;
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}
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return { type: type, data: data };
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};
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/**
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* Encodes multiple messages (payload).
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*
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* <length>:data
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*
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* Example:
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*
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* 11:hello world2:hi
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*
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* If any contents are binary, they will be encoded as base64 strings. Base64
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* encoded strings are marked with a b before the length specifier
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*
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* @param {Array} packets
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* @api private
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*/
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exports.encodePayload = function (packets, supportsBinary, callback) {
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if (typeof supportsBinary === 'function') {
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callback = supportsBinary;
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supportsBinary = null;
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}
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if (supportsBinary && hasBinary(packets)) {
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return exports.encodePayloadAsBinary(packets, callback);
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}
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if (!packets.length) {
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return callback('0:');
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}
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function encodeOne(packet, doneCallback) {
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exports.encodePacket(packet, supportsBinary, false, function(message) {
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doneCallback(null, setLengthHeader(message));
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});
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}
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map(packets, encodeOne, function(err, results) {
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return callback(results.join(''));
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});
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};
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function setLengthHeader(message) {
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return message.length + ':' + message;
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}
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/**
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* Async array map using after
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*/
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function map(ary, each, done) {
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var result = new Array(ary.length);
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var next = after(ary.length, done);
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for (var i = 0; i < ary.length; i++) {
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each(ary[i], function(error, msg) {
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result[i] = msg;
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next(error, result);
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});
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}
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}
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/*
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* Decodes data when a payload is maybe expected. Possible binary contents are
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* decoded from their base64 representation
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*
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* @param {String} data, callback method
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* @api public
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*/
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exports.decodePayload = function (data, binaryType, callback) {
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if (typeof data !== 'string') {
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return exports.decodePayloadAsBinary(data, binaryType, callback);
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}
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if (typeof binaryType === 'function') {
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callback = binaryType;
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binaryType = null;
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}
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if (data === '') {
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// parser error - ignoring payload
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return callback(err, 0, 1);
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}
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var length = '', n, msg, packet;
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for (var i = 0, l = data.length; i < l; i++) {
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var chr = data.charAt(i);
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if (chr !== ':') {
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length += chr;
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continue;
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}
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if (length === '' || (length != (n = Number(length)))) {
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// parser error - ignoring payload
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return callback(err, 0, 1);
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}
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msg = data.substr(i + 1, n);
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if (length != msg.length) {
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// parser error - ignoring payload
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return callback(err, 0, 1);
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}
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if (msg.length) {
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packet = exports.decodePacket(msg, binaryType, false);
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if (err.type === packet.type && err.data === packet.data) {
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// parser error in individual packet - ignoring payload
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return callback(err, 0, 1);
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}
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var more = callback(packet, i + n, l);
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if (false === more) return;
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}
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// advance cursor
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i += n;
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length = '';
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}
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if (length !== '') {
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// parser error - ignoring payload
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return callback(err, 0, 1);
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}
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};
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/**
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*
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* Converts a buffer to a utf8.js encoded string
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*
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* @api private
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*/
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function bufferToString(buffer) {
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var str = '';
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for (var i = 0, l = buffer.length; i < l; i++) {
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str += String.fromCharCode(buffer[i]);
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}
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return str;
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}
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/**
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*
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* Converts a utf8.js encoded string to a buffer
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*
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* @api private
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*/
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function stringToBuffer(string) {
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var buf = Buffer.allocUnsafe(string.length);
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for (var i = 0, l = string.length; i < l; i++) {
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buf.writeUInt8(string.charCodeAt(i), i);
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}
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return buf;
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}
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/**
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*
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* Converts an ArrayBuffer to a Buffer
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*
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* @api private
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*/
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function arrayBufferToBuffer(data) {
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// data is either an ArrayBuffer or ArrayBufferView.
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var length = data.byteLength || data.length;
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var offset = data.byteOffset || 0;
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return Buffer.from(data.buffer || data, offset, length);
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}
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/**
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* Encodes multiple messages (payload) as binary.
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*
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* <1 = binary, 0 = string><number from 0-9><number from 0-9>[...]<number
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* 255><data>
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*
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* Example:
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* 1 3 255 1 2 3, if the binary contents are interpreted as 8 bit integers
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*
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* @param {Array} packets
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* @return {Buffer} encoded payload
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* @api private
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*/
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exports.encodePayloadAsBinary = function (packets, callback) {
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if (!packets.length) {
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return callback(EMPTY_BUFFER);
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}
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map(packets, encodeOneBinaryPacket, function(err, results) {
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return callback(Buffer.concat(results));
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});
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};
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function encodeOneBinaryPacket(p, doneCallback) {
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function onBinaryPacketEncode(packet) {
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var encodingLength = '' + packet.length;
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var sizeBuffer;
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if (typeof packet === 'string') {
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sizeBuffer = Buffer.allocUnsafe(encodingLength.length + 2);
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sizeBuffer[0] = 0; // is a string (not true binary = 0)
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for (var i = 0; i < encodingLength.length; i++) {
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sizeBuffer[i + 1] = parseInt(encodingLength[i], 10);
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}
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sizeBuffer[sizeBuffer.length - 1] = 255;
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return doneCallback(null, Buffer.concat([sizeBuffer, stringToBuffer(packet)]));
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}
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sizeBuffer = Buffer.allocUnsafe(encodingLength.length + 2);
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sizeBuffer[0] = 1; // is binary (true binary = 1)
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for (var i = 0; i < encodingLength.length; i++) {
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sizeBuffer[i + 1] = parseInt(encodingLength[i], 10);
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}
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sizeBuffer[sizeBuffer.length - 1] = 255;
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doneCallback(null, Buffer.concat([sizeBuffer, packet]));
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}
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||
|
|
exports.encodePacket(p, true, true, onBinaryPacketEncode);
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Decodes data when a payload is maybe expected. Strings are decoded by
|
||
|
|
* interpreting each byte as a key code for entries marked to start with 0. See
|
||
|
|
* description of encodePayloadAsBinary
|
||
|
|
|
||
|
|
* @param {Buffer} data, callback method
|
||
|
|
* @api public
|
||
|
|
*/
|
||
|
|
|
||
|
|
exports.decodePayloadAsBinary = function (data, binaryType, callback) {
|
||
|
|
if (typeof binaryType === 'function') {
|
||
|
|
callback = binaryType;
|
||
|
|
binaryType = null;
|
||
|
|
}
|
||
|
|
|
||
|
|
var bufferTail = data;
|
||
|
|
var buffers = [];
|
||
|
|
var i;
|
||
|
|
|
||
|
|
while (bufferTail.length > 0) {
|
||
|
|
var strLen = '';
|
||
|
|
var isString = bufferTail[0] === 0;
|
||
|
|
for (i = 1; ; i++) {
|
||
|
|
if (bufferTail[i] === 255) break;
|
||
|
|
// 310 = char length of Number.MAX_VALUE
|
||
|
|
if (strLen.length > 310) {
|
||
|
|
return callback(err, 0, 1);
|
||
|
|
}
|
||
|
|
strLen += '' + bufferTail[i];
|
||
|
|
}
|
||
|
|
bufferTail = bufferTail.slice(strLen.length + 1);
|
||
|
|
|
||
|
|
var msgLength = parseInt(strLen, 10);
|
||
|
|
|
||
|
|
var msg = bufferTail.slice(1, msgLength + 1);
|
||
|
|
if (isString) msg = bufferToString(msg);
|
||
|
|
buffers.push(msg);
|
||
|
|
bufferTail = bufferTail.slice(msgLength + 1);
|
||
|
|
}
|
||
|
|
|
||
|
|
var total = buffers.length;
|
||
|
|
for (i = 0; i < total; i++) {
|
||
|
|
var buffer = buffers[i];
|
||
|
|
callback(exports.decodePacket(buffer, binaryType, true), i, total);
|
||
|
|
}
|
||
|
|
};
|