Raid2X

Raid2X is a software raid algorithm

• Pure JavaScript
• Support file Segmentation / Merge
• Support file Encrypt / Decrypt
• File would be divided into 2N parts (N mod 2 = 1)，and could be recovery by only N + 1 parts

Installing

npm install raid2x

Requires nodejs >= 0.10.x

Usage

Quick Test

var Raid2X = require('raid2x');
var filepath = "/Users/luphia/Documents/Workspace/Playground/logo.png";
var distination = "/Users/luphia/Desktop/";
var r2x = new Raid2X(filepath), r2x1, meta;
r2x.setSliceSize(61440);
meta = r2x.getMeta(true);
r2x1 = new Raid2X(meta);
for(var i = 0; i < meta.sliceCount; i++) {
	r2x1.importShard(r2x.getShard(i));
}
r2x1.save(distination + meta.name);

Initial Raid2X

var Raid2X = require("raid2x");
var r2x = new Raid2X([options]);

• options - {Buffer|File path|Metadata}

Metadata

You can also export the Metadata from an exist Raid2X over r2x.getMeta()

• name - [String] name of original file
• size - [INT] size of original file
• hash - [String] hash of original file (SHA1 + CRC)
• encFile - [Boolean] to switch
• encShard - [Boolean]
• sliceCount - [INT]
• sliceSize - [INT]
• duplicate - [Boolean]
• shardList - [String Array]

Load file

r2x.readFile("/path/to/your/file.txt", function(err, data) {
  if(err) { console.trace(e); }
  else {}
});

// You can also read a file by Buffer or Base64 string
var fs = require("fs");
var buffer = fs.readFileSync("/path/to/file.txt");
var base64 = buffer.toString('base64');

r2x.readBuffer(buffer);
r2x.readBase64(base64);

Copy to another place

var metadata = r2x.getMeta();
var copy = new Raid2X(metadata);
var shardCount = metadata.shardList.length;

var shard;
while(shard = r2x.nextShard()) {
  var progress = copy.importShard(shard);
  console.log(progress * 100 + "%");
  
  if(progress == 1) { break; }
}

If the file is divided into 2N shards, you can recovery a it by only N+1 shards

var recovery = new Raid2X(metadata);
for(var i = 0; i < metadata.shardList.length; i++) {
  if(i % 2 == 0 || i == r2x.attr.sliceCount) {
    recovery.importShard(r2x.getShard(i));
  }
}

var N = metadata.shardList.length / 2 + 1;
if(recovery.toBase64() == r2x.toBase64()) { console.log("recovery file with %d shards", N); }
else { console.log("recovery failed :("); }

Get a shard / Import a shard

var sample = new Raid2X(metadata);
var n = 0;

var type = "buffer";
var bufferShard = r2x.getShard(n, type);
sample.importBuffer(bufferShard);

type = "base64";
var base64Shard = r2x.getShard(n, type);
sample.importBase64(base64Shard);

• n - [INT] the order of the shard
• type - {buffer|base64} format of the shard

Export the file / Save the file

var bufferFile = r2x.toBinary();
var base64File = r2x.toBase64();

var writeStream = fs.createWriteStream('myBinaryFile');
writeStream.write(bufferFile);
writeStream.end();

Usage in the Web

• upload somefile

var r2x = new Raid2X();
r2x.readFile(file, function() {
  r2x.uploadAll(path, function(d) {
    console.log(d);
    if(d == 1) {
      console.log("upload complete");
    }
  });
});

• download somefile

var r2x = new Raid2X(meta);
r2x.downloadAll(path, function(d) {
  console.log(d);
  if(d == 1) {
    // save to local
    r2x.save();
  }
});