120 lines
2.7 KiB
TypeScript
120 lines
2.7 KiB
TypeScript
import EventEmitter from "events";
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import DHTCache from "@lumeweb/dht-cache";
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import { RPCCacheItem, RPCRequest, RPCResponse } from "@lumeweb/relay-types";
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import { get as getSwarm } from "../swarm";
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import { RPCServer } from "./server";
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// @ts-ignore
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import jsonStringify from "json-stringify-deterministic";
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// @ts-ignore
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import crypto from "hypercore-crypto";
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import NodeCache from "node-cache";
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import log from "../../log.js";
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export class RPCCache extends EventEmitter {
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private server: RPCServer;
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constructor(server: RPCServer) {
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super();
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this.server = server;
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this._swarm = getSwarm();
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this._dhtCache = new DHTCache(this._swarm, {
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protocol: "lumeweb.rpccache",
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logger: log.child({ module: "dht-cache" }),
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});
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this._data.on("del", (key: string) => {
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try {
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this.deleteItem(key);
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} catch {}
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});
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}
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private _dhtCache?: DHTCache;
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get dhtCache(): DHTCache {
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return this._dhtCache as DHTCache;
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}
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private _swarm?: any;
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get swarm(): any {
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return this._swarm;
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}
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private _data: NodeCache = new NodeCache({ stdTTL: 60 * 60 * 24 });
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get data(): NodeCache {
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return this._data;
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}
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public signResponse(item: RPCCacheItem): string {
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const field = item.value.signedField || "data";
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const updated = item.value.updated;
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// @ts-ignore
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let json = item.value[field];
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if (typeof json !== "string") {
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json = jsonStringify(json);
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}
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return this.server.signData(`${updated}${json}`);
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}
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public verifyResponse(pubkey: Buffer, item: RPCCacheItem): boolean | Buffer {
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const field = item.value.signedField || "data";
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const updated = item.value.updated;
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// @ts-ignore
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let json = item.value[field];
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if (typeof json !== "string") {
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json = jsonStringify(json);
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}
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try {
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if (
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!crypto.verify(
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Buffer.from(`${updated}${json}`),
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Buffer.from(item?.signature as string, "hex"),
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pubkey
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)
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) {
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return false;
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}
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} catch {
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return false;
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}
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return true;
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}
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public addItem(query: RPCRequest, response: RPCResponse) {
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const queryHash = RPCServer.hashQuery(query);
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const clonedResponse = { ...response };
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clonedResponse.updated = Date.now();
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const item = {
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value: clonedResponse,
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signature: "",
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};
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item.signature = this.signResponse(item);
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this._dhtCache?.addItem(queryHash);
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this._data.set(queryHash, item);
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}
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public deleteItem(queryHash: string): boolean {
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const cache = this._dhtCache?.cache;
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if (!cache?.includes(queryHash)) {
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throw Error("item does not exist");
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}
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this._dhtCache?.removeItem(queryHash);
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this._data.del(queryHash);
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return true;
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}
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}
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