@toolpad/utils/modern/workerRpc.js

Shared utilities used by Toolpad packages.

import { MessageChannel } from 'worker_threads';
import { errorFrom, serializeError } from "./errors.js";

/**
 * Helpers that are intended to set up rpc between a Node.js worker thread and the main thread.
 * Create the worker and pass a port in the workerData.
 *
 * On the main thread:
 *
 *     const rpcChannel = new MessageChannel()
 *     const worker = new Worker('./myWorker.js', {
 *       workerData: { rpcPort: rpcChannel.port1 },
 *       transferList: [rpcChannel.port1]
 *     })
 *
 *     // Depending of the direction of communication, either
 *     const client = createRpcClient(rpcChannel.port2)
 *     // or
 *     serveRpc(rpcChannel.port2, {
 *       myMethod
 *     })
 *
 * On the worker thread:
 *
 *     // Depending of the direction of communication, either
 *     const client = createRpcClient(workerData.rpcPort)
 *     // or
 *     serveRpc(workerData.rpcPort, {
 *       myMethod
 *     })
 *
 * Use multiple channels for bidirectional communication.
 */

// eslint-disable-next-line @typescript-eslint/no-explicit-any

export function createRpcClient(port, {
  timeout = 30000
} = {}) {
  return new Proxy({}, {
    get: (target, prop) => {
      if (typeof prop !== 'string') {
        return Reflect.get(target, prop);
      }
      return (...args) => {
        return new Promise((resolve, reject) => {
          const {
            port1,
            port2
          } = new MessageChannel();
          const timeoutId = setTimeout(() => {
            port1.close();
          }, timeout);
          port1.on('message', msg => {
            clearTimeout(timeoutId);
            if (msg.error) {
              reject(msg.error);
            } else {
              resolve(msg.result);
            }
          });
          port1.start();
          port.postMessage({
            method: prop,
            args,
            port: port2
          }, [port2]);
        });
      };
    }
  });
}
export function serveRpc(port, methods) {
  const methodMap = new Map(Object.entries(methods));
  port.on('message', async msg => {
    const method = methodMap.get(msg.method);
    if (method) {
      try {
        const result = await method(...msg.args);
        msg.port.postMessage({
          result
        });
      } catch (rawError) {
        msg.port.postMessage({
          error: serializeError(errorFrom(rawError))
        });
      }
    } else {
      msg.port.postMessage({
        error: new Error(`Method "${msg.method}" not found`)
      });
    }
  });
  port.start();
}