relay-plugin-eth/src/index.ts

import type { Plugin, PluginAPI } from "@lumeweb/interface-relay";
import fetch, { Request, RequestInit } from "node-fetch";
import NodeCache from "node-cache";
import { Client, Prover } from "./client/index.js";
import { MemoryStore } from "./client/memory-store.js";
import { computeSyncPeriodAtSlot } from "@lodestar/light-client/utils";
import { toHexString } from "@chainsafe/ssz";
import { DEFAULT_BATCH_SIZE } from "./client/constants.js";
import { handleGETRequest } from "./client/utils.js";

const EXECUTION_RPC_URL =
  "https://solemn-small-frost.discover.quiknode.pro/dbbe3dc75a8b828611df3f12722de5cc88214947/";

const CONSENSUS_RPC_URL = "https://www.lightclientdata.org";

interface ExecutionRequest {
  method: string;
  params: any[];
}

interface ConsensusCommitteeHashesRequest {
  start: number;
  count: number;
}

interface ConsensusCommitteePeriodRequest {
  period: number | "latest";
}

interface ConsensusBlockRequest {
  block: number;
}

let client: Client;

const RPC_NO_CACHE = [
  "eth_call",
  "eth_estimateGas",
  "eth_sendRawTransaction",
  "eth_getTransactionReceipt",
  "eth_getTransactionCount",
];

const plugin: Plugin = {
  name: "eth",
  async plugin(api: PluginAPI): Promise<void> {
    const prover = new Prover(CONSENSUS_RPC_URL);
    const store = new MemoryStore();
    client = new Client(prover, store, CONSENSUS_RPC_URL, EXECUTION_RPC_URL);
    await client.sync();
    client.provider.rpc.pluginApi = api;
    const provider = client.provider;

    api.registerMethod("consensus_committee_hashes", {
      cacheable: false,
      async handler(
        request: ConsensusCommitteeHashesRequest
      ): Promise<Uint8Array> {
        if (!(request?.start && typeof request.start == "number")) {
          throw new Error('start required and must be a number"');
        }
        if (!(request?.count && typeof request.count == "number")) {
          throw new Error('count required and must be a number"');
        }

        if (!client.isSynced) {
          await client.sync();
        }

        let hashes;

        try {
          hashes = store.getCommitteeHashes(request.start, request.count);
        } catch {
          await client.sync();
        }

        if (!hashes) {
          try {
            hashes = store.getCommitteeHashes(request.start, request.count);
          } catch (e) {
            return e;
          }
        }

        return hashes;
      },
    });

    api.registerMethod("consensus_committee_period", {
      cacheable: false,
      async handler(
        request: ConsensusCommitteePeriodRequest
      ): Promise<Uint8Array> {
        if (
          !(
            request?.period &&
            (typeof request.period == "number" || request.period === "latest")
          )
        ) {
          throw new Error('period required and must be a number or "latest"');
        }

        if (!client.isSynced) {
          await client.sync();
        }

        let committee;

        try {
          committee = store.getCommittee(
            request.period === "latest" ? client.latestPeriod : request.period
          );
        } catch {
          await client.sync();
        }

        if (!committee) {
          try {
            committee = store.getCommittee(
              request.period === "latest" ? client.latestPeriod : request.period
            );
          } catch (e) {
            return e;
          }
        }

        return committee;
      },
    });

    api.registerMethod("execution_request", {
      cacheable: false,
      async handler(request: ExecutionRequest): Promise<object> {
        const cache = provider.rpc.getCachedRequest(request);

        if (cache) {
          return cache;
        }

        if (provider.rpcMethodSupported(request.method)) {
          await provider.rpcMethod(request.method, request.params);
        } else {
          await provider.rpc.request(request);
        }
        let ret = provider.rpc.getCachedRequest(request);

        if (RPC_NO_CACHE.includes(request.method)) {
          provider.rpc.deleteCachedRequest(request);
        }
        // @ts-ignore
        return { ...ret, id: request.id ?? ret.id };
      },
    });

    api.registerMethod("consensus_optimistic_update", {
      cacheable: false,
      async handler(): Promise<object> {
        return await handleGETRequest(
          `${CONSENSUS_RPC_URL}/eth/v1/beacon/light_client/optimistic_update`
        );
      },
    });
    api.registerMethod("consensus_block", {
      cacheable: false,
      async handler(request: ConsensusBlockRequest): Promise<object> {
        try {
          BigInt(request?.block);
        } catch {
          throw new Error("block is required and must be a number");
        }

        const block = request?.block;

        if (
          BigInt(block) > BigInt(client.latestPeriod) ||
          !client.blockHashCache.has(request.block)
        ) {
          await client.sync();
        }

        if (
          !client.blockHashCache.has(request.block) &&
          !client.blockCache.has(request.block)
        ) {
          let state;
          try {
            const period = computeSyncPeriodAtSlot(request.block);
            state = await prover.getSyncUpdate(
              period,
              period,
              DEFAULT_BATCH_SIZE
            );
            await client.getExecutionFromBlockRoot(
              request.block as any,
              toHexString(state.attestedHeader.beacon.bodyRoot)
            );
          } catch {}
        }

        if (client.blockCache.has(request.block)) {
          client.blockCache.ttl(request.block);

          return client.blockCache.get(request.block);
        }

        const ret = await handleGETRequest(
          `${CONSENSUS_RPC_URL}/eth/v2/beacon/blocks/${request.block}`
        );
        client.blockCache.set(request.block, ret);

        return ret;
      },
    });
  },
};

export default plugin;