Bencode encoding and decoding, with both library and CLI versions available. The CLI version can decode bencode-formatted data from files or strings and output the result in JSON format.
npm install sloaix-node-bencodeBencode encoding and decoding, with both library and CLI versions available.
The bencode cli can decode bencode-formatted data from files or strings and output the result in JSON format.
``bashuse as a cli tool
npm i -g sloaix-node-bencode
pnpm i -g sloaix-node-bencode
yarn add global sloaix-node-bencode
pnpm i -D sloaix-node-bencode
yarn add -D sloaix-node-bencode
`
option -f means argument is a file path, otherwise it will be treated as a string.
option -p means output will be pretty json, otherwise it will be a single line.
`bash
# base usage
# will out put "hello"
bencode decode '5:hello'
# will output 123
bencode decode 'i123e'
# will output [1, 2, 3]
bencode decode 'li1ei2ei3ee'
# will output { a: 1, b: 2, c: 3 }
bencode decode 'd1:ai1e1:bi2e1:ci3ee'
# decode from file and print compressed json
bencode decode -f ./ubuntu-22.04.2-live-server-amd64.iso.torrent
# decode from file and print pretty json, output to file
bencode decode -fp ./ubuntu-22.04.2-live-server-amd64.iso.torrent > ./ubuntu.json
`
`typescript
import { Bencoder } from 'sloaix-node-bencode'
const data = 'hello'
// const data = 123
// const data = [1, 2, 3]
// const data = { a: 1, b: 2, c: 3 }
// const data = { a: [1, 2, 3], b: { c: 1, d: 2, e: 3 } }
// create encoder
const encoder = new Bencoder()
// encode result is a Unit8Array
// if encode a 'hello' string, result is [53, 58, 104, 101, 108, 108, 111], whitch is '5:hello' ascii code array
const result = await encoder.encode(data)
// write to file
writeFileSync('./bencode', result)
// open with text editor, you will see '5:hello' string.
`
This is a simple way of use
`typescript
import { Bdecoder } from 'sloaix-node-bencode'
// decode bitTorrent file
const torrent = './ubuntu-22.04.2-live-server-amd64.iso.torrent'
// create decoder
const decoder = new Bdecoder()
// if string is valid utf-8 string, it will be decoded to string, like 'hello'
// or it will be decoded to Uint8Array string (it's a custom format), like 'Unit8Array[number, number, number, ...]', such as pieces in torrent file
// d(source: BufReader | Uint8Array | Buffer, writer?: Writer): source can be Uint8Array or Buffer or BufReader, writer is optional,if you want to write result to stdout or file, you can pass a Writer
const result = decoder.decode(readFileSync(torrent))
`
!!!NOTE TAHT!!!
when decoding byte string, you will encounter two situations
#### 1. Byte string as value of the dict
when decode torrent file, the pieces is a byte string, but is not a valid utf-8 string, so it will be convert to Unit8Array, like [number, number, number, ...],the number is a byte
` typescript
// when decode torrent file, result is a js object, like this:
// {
// "announce": "https://torrent.ubuntu.com/announce",
// "announce-list": [
// [
// "https://torrent.ubuntu.com/announce"
// ],
// [
// "https://ipv6.torrent.ubuntu.com/announce"
// ]
// ],
// "comment": "Ubuntu CD releases.ubuntu.com",
// "created by": "mktorrent 1.1",
// "creation date": 1677174459,
// "info": {
// "length": 1975971840,
// "name": "ubuntu-22.04.2-live-server-amd64.iso",
// "piece length": 262144,
// "pieces": [42,56,162,55,...]
`
#### 2. Byte string as key of the dict
when decode a response of a tracker scrape, such as https://torrent.ubuntu.com/scrape
part of response is below:
`txt
d5:filesd20:Fx��x0�Wsz�����O�d8:completei38e10:downloadedi0e10:incompletei0e4:name33:lubuntu-16.04.6-desktop-amd64.isoe20:��+\0��*aT�5q��L�d8:completei312e10:downloadedi7e10:incompletei12e4:name36:ubuntu-18.04.6-live-server-amd64.isoe20:���<�!�ɺ��S����d8:completei25e10:downloadedi0e10:incompletei0e4:name32:kubuntu-16.04.6-desktop-i386.isoe20:#ܷx] �����t'zf��d8:completei184e10:downloadedi5e10:incompletei9e4:name37:ubuntu-mate-22.04.3-desktop-amd64.isoe20:���D��429...
`
Obviously, each key of the files dict is infohash(20 bytes), it's a invalid utf-8 string.
So, when decode a response of a tracker scrape, the invliad utf-8 key will be converted to a "Unit8Array[number, number, number, ...]" string
like this:
`json
{
files: {
"Unit8Array[0,70,120,242,226,120,16,48,188,87,115,122,135,250,247,170,251,23,79,248]": {
complete: 38,
downloaded: 0,
incomplete: 0,
name: "lubuntu-16.04.6-desktop-amd64.iso"
},
"Unit8Array[0,178,28,249,43,92,48,207,246,42,18,97,84,194,53,113,151,154,76,171]": {
complete: 310,
downloaded: 6,
incomplete: 12,
name: "ubuntu-18.04.6-live-server-amd64.iso"
}
}
`
if you want to confirm the key is a Unit8Array string or not, you can use Bdecoder.isByteKey function
`typescript
import { Bdecoder } from 'sloaix-node-bencode'
const key = 'Unit8Array[0,70,120,242,226,120,16,48,188,87,115,122,135,250,247,170,251,23,79,248]'
const result = Bdecoder.isByteKey(key) // true
`
if you want to convert it to Unit8Array:
`typescript
import { Bdecoder } from 'sloaix-node-bencode'
const key = 'Unit8Array[0,70,120,242,226,120,16,48,188,87,115,122,135,250,247,170,251,23,79,248]'
if(Bdecoder.isByteKey(key)){
const result = Bdecoder.byteKeyToUint8Array(key)
// [0,70,120,242,226,120,16,48,188,87,115,122,135,250,247,170,251,23,79,248]
}
`
`bash
npm i && npm run build && npm run test