Message Port

oRPC offers built-in support for common Message Port implementations, enabling easy internal communication between different processes.

Environment	Documentation
Electron Message Port	Adapter Guide
Browser (extension background to popup/content, window to window, etc.)	Adapter Guide
Node.js Worker Threads Port	Adapter Guide

Basic Usage

Message Ports work by establishing two endpoints that can communicate with each other:

bridge

const channel = new MessageChannel()
const serverPort = channel.port1
const clientPort = channel.port2

server

import { RPCHandler } from '@orpc/server/message-port'

const handler = new RPCHandler(router)

handler.upgrade(serverPort, {
  context: {}, // Provide initial context if needed
})

serverPort.start()

client

import { RPCLink } from '@orpc/client/message-port'

const link = new RPCLink({
  port: clientPort,
})

clientPort.start()

INFO

This only shows how to configure the link. For full client examples, see Client-Side Clients.

Transfer

By default, oRPC serializes request/response messages to string/binary data before sending over message port. If needed, you can define the transfer option to utilize full power of MessagePort: postMessage() method, such as transferring ownership of objects to the other side or support unserializable objects like OffscreenCanvas.

handler

const handler = new RPCHandler(router, {
  experimental_transfer: (message, port) => {
    const transfer = deepFindTransferableObjects(message) // implement your own logic
    return transfer.length ? transfer : null // only enable when needed
  }
})

link

const link = new RPCLink({
  port: clientPort,
  experimental_transfer: (message) => {
    const transfer = deepFindTransferableObjects(message) // implement your own logic
    return transfer.length ? transfer : null // only enable when needed
  }
})

WARNING

When transfer returns an array, messages using the structured clone algorithm for sending, which doesn't support all data types such as Event Iterator's Metadata. So I recommend you only enable this when needed.

TIP

The transfer option run after RPC JSON Serializer so you can combine them together to support more data types.