RocketRPC is typesafe RPC library which gets out of your way. Define methods in your server, which you can access instantly in your client - complete with auto-completions and type-checking.

Click on the image below to watch @akash-joshi talk about RocketRPC at Svelte London:

Install the package

npm i rocketrpc

Note: On the client side, all functions return a Promise with the result by default, because of the asynchronous nature of sockets. So, all passed functions are also modified to return a Promise.

import { Client } from "rocketrpc";
import { API } from "../server";

const client = Client<API>("http://localhost:8080");

const { listFiles, prisma } = client;

const main = async () => {
  // use prisma on the client
  console.log(await prisma.user.findMany());

  // passing multiple parameters to the function
  console.log(await client.sum(12, 20));

  // get server details
  console.log(await listFiles());
};

main();

import { Server } from "rocketrpc";
import { PrismaClient } from "@prisma/client";

import listFiles from "./apis/listFiles";

const api = {
  // initialize Prisma once
  prisma: new PrismaClient();

  sum: (x: number, y: number) => x + y,

  // Fetch all files on server
  listFiles,
};

export type API = typeof api;

Server(8080, api);

At the moment, any error on the server-side is sent to std:error and thrown on the client side.

Try running the examples locally!

The socket.io client being used by rocketRPC is accessible via the _rocketRpcContext key.

In short, the library depends on Websockets, Object Proxies, and Typescript generics to work. In detail:

We use socket.io for fast and reliable socket connections. Websockets can be lighter than HTTP requests when a large number of connections are needed. Also, they have a smaller code footprint than HTTP requests. Their usage is anyways abstracted away in the codebase, and they can be replaced with any other technology if needed.

The framework utilizes Object Proxies get control over the client object. Any function call made on a property of the client object (or on a deconstructed property), like

client.functionOne();

// or

const { functionOne } = client;
functionOne();

is handled by a get property which has been set on the Object Proxy here.

You can go through the code to see how it uses the property name and parameters to make a socket call to the server.

All of the auto-complete goodness that the framework provides throughout the app depends on Typescript generics. On the server side, the type is directly applied on the API object,

const api: API = { ...yourApi };

while on the client side it's passed to the Client initializer.

const client = Client<API>(endpoint);

The client function is actually a generic, which accepts the type provided by the user and applies Promise to the return type of each of them. It's a very Typescript-specific piece of code but you can read it here.

If you find RocketRPC enjoyable to work with and wish to show your support for the project, you can express your gratitude by sponsoring it through GitHub Sponsors!

Furthermore, if your company is currently utilizing RocketRPC and would like to support its long-term maintenance, please refer to the sponsorship tiers.

RocketConnect

Pull requests are welcome. You'll probably find lots of improvements to be made.

Open issues for feedback, requesting features, reporting bugs or discussing ideas.