@savant/ws-middleware

@savant/ws-middleware is a library that enables you to add remote WebSocket support to any pre-existing class or function, while still retaining the existing syntax. This is particularly useful when you want to use the same syntax in both local and remote contexts.

ws-middleware achieves this by wrapping the class or function with a WebSocket server, which then proxies the calls to the remote context. This allows you to use the same syntax in both the local and remote contexts, without having to worry about the underlying communication mechanism.

See examples below for further explanation

Installation

To install @savant/ws-middleware, run the following command:

npm install @savant/ws-middleware

Usage

Here's an example of how to use @savant/ws-middleware with a class:

class Animal {
    constructor(name) {
        console.log("(...Animal) constructed", name);
        this.name = name;
    }

    getName (name) {
        return name;
    }

    setAge (age) {
        console.log("(...Animal) age set: " + age);
        this.age = age;
    }

    async wait10Seconds () {
        return new Promise(r => setTimeout(() => {r("waited 10 seconds!")}, 10000));
    }
}


// Host / Server
(async () => {
    const { Host } = require("@savant/ws-middleware");
    const server = new Host(Animal);
    server.listen(3000);
})();


// Client
(async () => {
    const { Client } = require("@savant/ws-middleware");

    // Wrap our Animal class with a WebSocket client
    const RemoteAnimal = Client(Animal, "ws://127.0.0.1:3000");

    const remoteAnimal = new RemoteAnimal("dog");
    const result = await remoteAnimal.wait10Seconds(10);
    console.log("Result:", result); // prints "Result: waited 10 seconds!"
})();

On the "host" or "server" side, we use the Host function provided by @savant/ws-middleware to wrap the Animal class with a WebSocket server. On the "client" side, we use the Client function to create a proxy to the remote Animal class. We can then use this proxy as if it were a local instance of the Animal class, while the underlying communication is handled transparently by @savant/ws-middleware. Here's an example of how to use @savant/ws-middleware with a function:

function add(a, b) {
    return a + b;
}

// Host / Server
(async () => {
    const { Host } = require("@savant/ws-middleware");
    const server = new Host(add);
    server.listen(3000);
})();

// Client
(async () => {
    const { Client } = require("@savant/ws-middleware");
    const remoteAdd = Client(add, "ws://127.0.0.1:3000");
    const result = remoteAdd(1, 2);
    console.log("Result:", result); // prints "Result: 3"
})();

Additional Examples

async function getData(url) {
    const response = await fetch(url);
    return response.json();
}

// Host / Server
(async () => {
    const { Host } = require("@savant/ws-middleware");
    const server = new Host(getData);
    server.listen(3000);
})();

// Client
(async () =>
    const { Client } = require("@savant/ws-middleware");
    const remoteGetData = Client(getData, "ws://127.0.0.1:3000");

    const data = await remoteGetData("https://api.example.com/data");
    console.log(data); // prints the JSON data returned by the API
})();