104 lines
2.3 KiB
JavaScript
104 lines
2.3 KiB
JavaScript
/*!
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* base64id v0.1.0
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*/
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/**
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* Module dependencies
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*/
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var crypto = require('crypto');
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/**
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* Constructor
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*/
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var Base64Id = function() { };
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/**
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* Get random bytes
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*
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* Uses a buffer if available, falls back to crypto.randomBytes
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*/
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Base64Id.prototype.getRandomBytes = function(bytes) {
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var BUFFER_SIZE = 4096
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var self = this;
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bytes = bytes || 12;
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if (bytes > BUFFER_SIZE) {
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return crypto.randomBytes(bytes);
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}
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var bytesInBuffer = parseInt(BUFFER_SIZE/bytes);
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var threshold = parseInt(bytesInBuffer*0.85);
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if (!threshold) {
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return crypto.randomBytes(bytes);
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}
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if (this.bytesBufferIndex == null) {
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this.bytesBufferIndex = -1;
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}
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if (this.bytesBufferIndex == bytesInBuffer) {
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this.bytesBuffer = null;
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this.bytesBufferIndex = -1;
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}
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// No buffered bytes available or index above threshold
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if (this.bytesBufferIndex == -1 || this.bytesBufferIndex > threshold) {
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if (!this.isGeneratingBytes) {
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this.isGeneratingBytes = true;
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crypto.randomBytes(BUFFER_SIZE, function(err, bytes) {
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self.bytesBuffer = bytes;
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self.bytesBufferIndex = 0;
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self.isGeneratingBytes = false;
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});
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}
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// Fall back to sync call when no buffered bytes are available
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if (this.bytesBufferIndex == -1) {
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return crypto.randomBytes(bytes);
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}
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}
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var result = this.bytesBuffer.slice(bytes*this.bytesBufferIndex, bytes*(this.bytesBufferIndex+1));
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this.bytesBufferIndex++;
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return result;
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}
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/**
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* Generates a base64 id
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*
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* (Original version from socket.io <http://socket.io>)
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*/
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Base64Id.prototype.generateId = function () {
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var rand = Buffer.alloc(15); // multiple of 3 for base64
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if (!rand.writeInt32BE) {
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return Math.abs(Math.random() * Math.random() * Date.now() | 0).toString()
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+ Math.abs(Math.random() * Math.random() * Date.now() | 0).toString();
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}
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this.sequenceNumber = (this.sequenceNumber + 1) | 0;
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rand.writeInt32BE(this.sequenceNumber, 11);
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if (crypto.randomBytes) {
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this.getRandomBytes(12).copy(rand);
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} else {
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// not secure for node 0.4
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[0, 4, 8].forEach(function(i) {
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rand.writeInt32BE(Math.random() * Math.pow(2, 32) | 0, i);
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});
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}
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return rand.toString('base64').replace(/\//g, '_').replace(/\+/g, '-');
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};
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/**
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* Export
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*/
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exports = module.exports = new Base64Id();
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