81 lines
2.1 KiB
JavaScript
81 lines
2.1 KiB
JavaScript
// Copyright IBM Corp. 2014,2016. All Rights Reserved.
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// Node module: loopback-connector
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// This file is licensed under the MIT License.
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// License text available at https://opensource.org/licenses/MIT
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'use strict';
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var createPromiseCallback = require('./utils').createPromiseCallback;
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var msgpack = require('msgpack5');
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module.exports = BinaryPacker;
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/**
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* Create a new Packer instance that can be used to convert between JavaScript
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* objects and a binary representation in a Buffer.
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*
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* Compared to JSON, this encoding preserves the following JavaScript types:
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* - Date
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*/
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function BinaryPacker() {
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this._packer = msgpack({ forceFloat64: true });
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this._packer.register(1, Date, encodeDate, decodeDate);
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}
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/**
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* Encode the provided value to a `Buffer`.
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*
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* @param {*} value Any value (string, number, object)
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* @callback {Function} cb The callback to receive the parsed result.
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* @param {Error} err
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* @param {Buffer} data The encoded value
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* @promise
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*/
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BinaryPacker.prototype.encode = function(value, cb) {
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cb = cb || createPromiseCallback();
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try {
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// msgpack5 returns https://www.npmjs.com/package/bl instead of Buffer
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// use .slice() to convert to a Buffer
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var data = this._packer.encode(value).slice();
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setImmediate(function() {
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cb(null, data);
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});
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} catch (err) {
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setImmediate(function() {
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cb(err);
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});
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}
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return cb.promise;
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};
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/**
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* Decode the binary value back to a JavaScript value.
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* @param {Buffer} binary The binary input.
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* @callback {Function} cb The callback to receive the composed value.
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* @param {Error} err
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* @param {*} value Decoded value.
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* @promise
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*/
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BinaryPacker.prototype.decode = function(binary, cb) {
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cb = cb || createPromiseCallback();
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try {
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var value = this._packer.decode(binary);
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setImmediate(function() {
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cb(null, value);
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});
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} catch (err) {
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setImmediate(function() {
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cb(err);
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});
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}
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return cb.promise;
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};
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function encodeDate(obj) {
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return new Buffer(obj.toISOString(), 'utf8');
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}
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function decodeDate(buf) {
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return new Date(buf.toString('utf8'));
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}
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