hyperswarm-web/dist/index.js

146 lines
4.5 KiB
JavaScript

// @ts-ignore
import DhtNode from "@hyperswarm/dht-relay";
// @ts-ignore
import Stream from "@hyperswarm/dht-relay/ws";
// @ts-ignore
import { Buffer } from "buffer";
// @ts-ignore
// @ts-ignore
import { blake2b } from "libskynet";
// @ts-ignore
import { registryRead } from "libkmodule";
import { unpack } from "msgpackr";
import randomNumber from "random-number-csprng";
const REGISTRY_DHT_KEY = "lumeweb-dht-node";
export default class DHT {
_options;
_relays = new Map();
_activeRelays = new Map();
_maxConnections = 10;
_inited = false;
constructor(opts = {}) {
// @ts-ignore
opts.custodial = false;
this._options = opts;
}
ready() {
if (this._inited) {
return Promise.resolve();
}
this._inited = true;
return this.fillConnections();
}
get relays() {
return [...this._relays.keys()];
}
async addRelay(pubkey) {
let entry = await registryRead(Uint8Array.from(Buffer.from(pubkey, "hex")), hashDataKey(REGISTRY_DHT_KEY));
if (entry[1] || !entry[0]?.exists) {
return false;
}
let host;
try {
host = unpack(entry[0].entryData);
}
catch (e) {
return false;
}
const [domain, port] = host.split(":");
if (isNaN(parseInt(port))) {
return false;
}
this._relays.set(pubkey, `wss://${domain}:${port}/`);
if (this._inited) {
await this.fillConnections();
}
return true;
}
removeRelay(pubkey) {
if (!this._relays.has(pubkey)) {
return false;
}
if (this._activeRelays.has(pubkey)) {
this._activeRelays.get(pubkey).destroy();
this._activeRelays.delete(pubkey);
}
this._relays.delete(pubkey);
return true;
}
clearRelays() {
[...this._relays.keys()].forEach(this.removeRelay);
}
async isServerAvailable(connection) {
return new Promise((resolve) => {
const ws = new WebSocket(connection);
ws.addEventListener("open", () => {
ws.close();
resolve(true);
});
ws.addEventListener("error", () => {
resolve(false);
});
});
}
async connect(pubkey, options = {}) {
if (this._activeRelays.size === 0) {
throw new Error("Failed to find an available relay");
}
let index = 0;
if (this._activeRelays.size > 1) {
index = await randomNumber(0, this._activeRelays.size - 1);
}
const node = this._activeRelays.get([...this._activeRelays.keys()][index]);
return node.connect(pubkey, options);
}
async fillConnections() {
let available = [];
const updateAvailable = () => {
available = [...this._relays.keys()].filter((x) => ![...this._activeRelays.keys()].includes(x));
};
updateAvailable();
let relayPromises = [];
while (this._activeRelays.size <=
Math.min(this._maxConnections, available.length)) {
if (0 === available.length) {
break;
}
let relayIndex = 0;
if (available.length > 1) {
relayIndex = await randomNumber(0, available.length - 1);
}
const connection = this._relays.get(available[relayIndex]);
if (!(await this.isServerAvailable(connection))) {
available.splice(relayIndex, 1);
this.removeRelay(available[relayIndex]);
continue;
}
const node = new DhtNode(new Stream(true, new WebSocket(connection)), this._options);
this._activeRelays.set(available[relayIndex], node);
updateAvailable();
relayPromises.push(node.ready());
}
return Promise.allSettled(relayPromises);
}
}
export function hashDataKey(dataKey) {
return blake2b(encodeUtf8String(dataKey));
}
function encodeUtf8String(str) {
const byteArray = stringToUint8ArrayUtf8(str);
const encoded = new Uint8Array(8 + byteArray.length);
encoded.set(encodeNumber(byteArray.length));
encoded.set(byteArray, 8);
return encoded;
}
function stringToUint8ArrayUtf8(str) {
return Uint8Array.from(Buffer.from(str, "utf-8"));
}
function encodeNumber(num) {
const encoded = new Uint8Array(8);
for (let index = 0; index < encoded.length; index++) {
encoded[index] = num & 0xff;
num = num >> 8;
}
return encoded;
}