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