node-bencode npm version
Bencode 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.
# use as a cli tool npm i -g sloaix-node-bencode pnpm i -g sloaix-node-bencode yarn add global sloaix-node-bencode # use as a libary npm i -D 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.
# 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
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
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
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
// 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,...]
when decode a response of a tracker scrape, such as https://torrent.ubuntu.com/scrape
part of response is below:
d5:filesd20:Fx��x0�Wsz�����O�d8:completei38e10:downloadedi0e10:incompletei0e4:name33:lubuntu-16.04.6-desktop-amd64.isoe20:��+0円��*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:
{
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
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:
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] }
npm i && npm run build && npm run test # PASS __test__/encode.test.ts # PASS __test__/decoder.test.ts # PASS __test__/utf8.test.ts # PASS __test__/cli.test.ts # Test Suites: 4 passed, 4 total # Tests: 39 passed, 39 total # Snapshots: 0 total # Time: 4.428 s, estimated 5 s