142 lines
3.7 KiB
JavaScript
142 lines
3.7 KiB
JavaScript
/*global Blob,File*/
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/**
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* Module requirements
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*/
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var isArray = require('isarray');
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var isBuf = require('./is-buffer');
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/**
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* Replaces every Buffer | ArrayBuffer in packet with a numbered placeholder.
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* Anything with blobs or files should be fed through removeBlobs before coming
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* here.
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*
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* @param {Object} packet - socket.io event packet
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* @return {Object} with deconstructed packet and list of buffers
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* @api public
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*/
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exports.deconstructPacket = function(packet){
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var buffers = [];
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var packetData = packet.data;
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function _deconstructPacket(data) {
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if (!data) return data;
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if (isBuf(data)) {
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var placeholder = { _placeholder: true, num: buffers.length };
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buffers.push(data);
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return placeholder;
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} else if (isArray(data)) {
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var newData = new Array(data.length);
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for (var i = 0; i < data.length; i++) {
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newData[i] = _deconstructPacket(data[i]);
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}
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return newData;
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} else if ('object' == typeof data && !(data instanceof Date)) {
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var newData = {};
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for (var key in data) {
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newData[key] = _deconstructPacket(data[key]);
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}
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return newData;
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}
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return data;
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}
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var pack = packet;
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pack.data = _deconstructPacket(packetData);
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pack.attachments = buffers.length; // number of binary 'attachments'
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return {packet: pack, buffers: buffers};
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};
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/**
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* Reconstructs a binary packet from its placeholder packet and buffers
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*
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* @param {Object} packet - event packet with placeholders
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* @param {Array} buffers - binary buffers to put in placeholder positions
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* @return {Object} reconstructed packet
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* @api public
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*/
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exports.reconstructPacket = function(packet, buffers) {
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var curPlaceHolder = 0;
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function _reconstructPacket(data) {
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if (data && data._placeholder) {
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var buf = buffers[data.num]; // appropriate buffer (should be natural order anyway)
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return buf;
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} else if (isArray(data)) {
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for (var i = 0; i < data.length; i++) {
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data[i] = _reconstructPacket(data[i]);
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}
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return data;
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} else if (data && 'object' == typeof data) {
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for (var key in data) {
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data[key] = _reconstructPacket(data[key]);
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}
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return data;
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}
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return data;
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}
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packet.data = _reconstructPacket(packet.data);
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packet.attachments = undefined; // no longer useful
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return packet;
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};
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/**
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* Asynchronously removes Blobs or Files from data via
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* FileReader's readAsArrayBuffer method. Used before encoding
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* data as msgpack. Calls callback with the blobless data.
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*
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* @param {Object} data
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* @param {Function} callback
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* @api private
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*/
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exports.removeBlobs = function(data, callback) {
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function _removeBlobs(obj, curKey, containingObject) {
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if (!obj) return obj;
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// convert any blob
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if ((global.Blob && obj instanceof Blob) ||
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(global.File && obj instanceof File)) {
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pendingBlobs++;
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// async filereader
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var fileReader = new FileReader();
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fileReader.onload = function() { // this.result == arraybuffer
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if (containingObject) {
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containingObject[curKey] = this.result;
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}
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else {
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bloblessData = this.result;
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}
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// if nothing pending its callback time
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if(! --pendingBlobs) {
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callback(bloblessData);
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}
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};
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fileReader.readAsArrayBuffer(obj); // blob -> arraybuffer
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} else if (isArray(obj)) { // handle array
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for (var i = 0; i < obj.length; i++) {
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_removeBlobs(obj[i], i, obj);
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}
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} else if (obj && 'object' == typeof obj && !isBuf(obj)) { // and object
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for (var key in obj) {
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_removeBlobs(obj[key], key, obj);
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}
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}
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}
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var pendingBlobs = 0;
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var bloblessData = data;
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_removeBlobs(bloblessData);
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if (!pendingBlobs) {
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callback(bloblessData);
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}
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};
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