It sorts dictionary entries incorrectly.

Bug

https://github.com/webtorrent/node-bencode/blob/2fa2c7ea7d97791a0c7f0cb3dd0bb098c014738f/lib/encode.js#L80-L81

 // fix for issue #13 - sorted dicts 
 const keys = Object.keys(data).sort() 

This is not the correct way of sorting dictionary entries.

When you say “strings” in the context of Bencoding, you mean “binary strings,” or more specifically, “8-bit byte sequences.”

BEP 52 — The BitTorrent protocol specification version 2

Note that, in the context of bencoding, strings, including dictionary keys, are arbitrary byte sequences (uint8_t[]).

And Array.prototype.sort compares 16-bit units by default.

If compareFn is not supplied, all non-undefined array elements are sorted by converting them to strings and comparing strings in UTF-16 code units order.

The simple .sort() results in a different order (sorted_in_utf16) than the correct one (sorted_in_utf8). Observe:

const A = String.fromCodePoint(0xFF61);
const B = String.fromCodePoint(0x10002);
const sorted_in_utf8 = [A, B].sort((a, b) => Buffer.compare(Buffer.from(a), Buffer.from(b))); // [A, B]
const sorted_in_utf16 = [A, B].sort(); // [B, A]

Related issues

• https://github.com/webtorrent/node-bencode/issues/13
• https://github.com/webtorrent/node-bencode/issues/88

Comienza en lib/encode.js, en el código de ordenación de claves de diccionario enlazado en la issue. Reproduce la diferencia entre la ordenación UTF-16 y la ordenación por secuencia de bytes usando los puntos de código proporcionados y, después, inspecciona las pruebas existentes del encoder. Se considera terminado cuando las claves de diccionario se ordenan según sus secuencias de bytes bencoded, incluido el caso no ASCII descrito aquí.