# node-bencode [![build status](https://secure.travis-ci.org/themasch/node-bencode.png)](http://travis-ci.org/themasch/node-bencode)

A node library for encoding and decoding bencoded data,
according to the [BitTorrent specification](http://www.bittorrent.org/beps/bep_0003.html).

## Index

- [About BEncoding](#about-bencoding)
- [Installation](#install-with-npm)
- [Performance](#performance)
- [Usage](#usage)
- [API](#api)

## About BEncoding

from [Wikipedia](https://en.wikipedia.org/wiki/Bencoding):

Bencode (pronounced like B encode) is the encoding used by the peer-to-peer
file sharing system BitTorrent for storing and transmitting loosely structured data.

It supports four different types of values:
- byte strings
- integers
- lists
- dictionaries

Bencoding is most commonly used in torrent files.
These metadata files are simply bencoded dictionaries.

## Install with [npm](http://npmjs.org)

```
npm install bencode
```

## Performance

### encode
```
bencode x 7,939 ops/sec ±2.22% (74 runs sampled)
bencoding x 5,632 ops/sec ±1.47% (86 runs sampled)
dht-bencode x 6,403 ops/sec ±3.45% (87 runs sampled)
bncode x 5,106 ops/sec ±3.63% (82 runs sampled)
dht.js x 7,972 ops/sec ±2.22% (84 runs sampled)
```

### decode
```
bencode x 29,588 ops/sec ±0.75% (99 runs sampled)
bencoding x 27,844 ops/sec ±1.97% (95 runs sampled)
dht-bencode x 22,975 ops/sec ±1.84% (90 runs sampled)
bncode x 990 ops/sec ±2.71% (88 runs sampled)
dht.js x 19,103 ops/sec ±2.14% (89 runs sampled)
```

*all benchmarks from an Intel Core2Duo@2.6GHz with node v0.10.3.*

## Usage

```javascript
var bencode = require( 'bencode' )
```

### Encoding

```javascript

var data = {
  string: 'Hello World',
  integer: 12345,
  dict: {
    key: 'This is a string within a dictionary'
  },
  list: [ 1, 2, 3, 4, 'string', 5, {} ]
}

var result = bencode.encode( data )

```

#### Output

```
d4:dictd3:key36:This is a string within a dictionarye7:integeri12345e4:listli1ei2ei3ei4e6:stringi5edee6:string11:Hello Worlde
```

### Decoding

```javascript
var data   = new Buffer( 'd6:string11:Hello World7:integeri12345e4:dictd3:key36:This is a string within a dictionarye4:litli1ei2ei3ei4e6:stringi5edeee' )
var result = bencode.decode( data )
```

#### Output

```javascript
{
  string: <Buffer 48 65 6c 6c 6f 20 57 6f 72 6c 64>,
  integer: 12345,
  dict: {
    key: <Buffer 54 68 69 73 20 69 73 20 61 20 73 74 72 69 6e 67 20 77 69 74 68 69 6e 20 61 20 64 69 63 74 69 6f 6e 61 72 79>
  },
  list: [ 1, 2, 3, 4, <Buffer 73 74 72 69 6e 67>, 5, {} ]
}
```

Automagically convert bytestrings to strings:

```javascript
var result = bencode.decode( data, 'utf8' )
```

#### Output

```javascript
{
  string: 'Hello World',
  integer: 12345,
  dict: {
    key: 'This is a string within a dictionary'
  },
  list: [ 1, 2, 3, 4, 'string', 5, {} ]
}
```

## API

### bencode.encode( *data* )

> `Buffer` | `Array` | `String` | `Object` | `Number` __data__

Returns `Buffer`

### bencode.decode( *data*, *encoding* )

> `Buffer` __data__
> `String` __encoding__

If `encoding` is set, bytestrings are
automatically converted to strings.

Returns `Object` | `Array` | `Buffer` | `String` | `Number`