uWebSockets.js Router

A low code approach to routing and setting up an http server with uWebSockets.js . It also provides helper functions for easily setting up middleware (e.g. authentication) and cached file serving while keeping the code added on top of the underlying uWebSockets.js app as low as possible.

Check out the starter kit for extensive documentation on its usage:

https://github.com/gudatr/uws-node-starter

Installation

Package:

npm install uws-router

Import:

    import { Router } from "uws-router";

Usage

Routing

The router setup will link to the functions defined on your controllers. Its structure could be something like this:

    let router = new Router(false, {
    //Use SSLApp and add your SSL config here if needed
    //See the μWebSockets.js docs for more info
    //cert_file_name: 'server.cert',
    //key_file_name: 'server.key'
});

This initializes a new router. If you choose to use SSL for https, you have to supply the key and cert file names. Otherwise a http app will be created.

router.endpoint('get', Controller.async);

router.group('examples', () => {

    router.endpoint('get', Controller.sync);

    router.middleware(ExampleMiddleware1, () => {

        router.endpoint('post', Controller.async, undefined, true);

        router.middleware(ExampleMiddleware2, () => {

            router.endpoint('get', Controller.middleware, 'alias');

        });

    });

    router.serveFileRelative('./images/logo.jpg', 'file');

});

Intializes the following routes pointing to the assigned controller functions:

• GET: /async
• POST: /examples/sync
• POST: /examples/async
• get: /examples/alias
• GET: /examples/file

The first route is only matched by a GET-Request to /async

The second route is only matched by a POST-Request to /group/sync

The third route passes through ExampleMiddleware1 before its handler is called. The body of the request is skipped as the skipBody parameter is set.

The fourth route passes through ExampleMiddleware1 and then ExampleMiddleware2 before its handler is called. It also has an alias that defines the endpoint's name.

The fifth route serves the file 'logo.jpg' that lies in a folder images relative to the router file. For easily copying assets and maintaining the path this way during a typescript build, checkout the package simple-copy-files.

router.listen("127.0.0.1", 8080, (isListening) => {
    console.log(isListening ? `Listening on port ${port}!` : `Error: Could not listen on port ${port}!`)
})

Finally you need call listen on your router to make it listen for incoming requests. This example will launch on port 8080 on localhost / 127.0.0.1. isListening will contain the socket if successful, which we won't be using.

Controllers

Please take note, that you do not have to use the controller scheme or something similar at all, you can also supply functions directly to the router endpoints.

    export default class Controller {

        public static async(request: RequestData) {
            request.end('Controller.async called');
        }

        public static sync(request: RequestData) {
            request.end('Controller.sync called');
        }

        public static middleware(request: RequestData) {
            request.end('Controller.middleware called');
        }
    }

For the best experience the handler methods should be static.

If you require state within your controllers or want e.g. the possibility of dependency injection, please take note that the "this" relation will be lost in the endpoint function.

To prevent this you have three options.

You can either set the object to be bound to "this" in the endpoint:

router.endpoint('get', controller.endpoint(request), 'endpoint', controller);

Or the group function:

app.group('group', () => {

    router.endpoint('get', controller.endpoint1);
    router.endpoint('get', controller.endpoint2);
    router.endpoint('get', controller.endpoint3);

}, controller);

Or define a new anonymous function like this:

router.endpoint('get', (req) => controller.endpoint(req));

The last option will add another function call on top of your handler though.

Middleware

The router allows you to define middlewares that can preprocess requests for multiple endpoints. This way you can for example add an authentication layer with 2 lines of code for all your routes even if you already have hundreds defined.

    let Middleware = async function (request: RequestData, next: NextFunction): void {
        request.writeStatus("202 Accepted");
        await next(request);
    }

This middleware writes the HTTP status code 202 to our response. The next parameter specifies which function will be called when the middleware was successfully passed. Otherwise you could for example end the request and return without calling the next function.

Files

To serve files there is the function serveFile on the router that generates a GET endpoint with the specified alias. It will respond with the file and also allows you to specify a cache duration before the file is reloaded from storage.

RequestData

The RequestData class is a wrapper around uws' request which is necessary for async functions as uws' request is stack-allocated an therefore stops existing once the base request handler finishes. Accessing the original request after this will cause an error.

It also wraps around uws' response and handles connection termination. The write-methods will return false once the connection is terminated. You can also use hasEnded() on the RequestData object to check if the connection was terminated. This can be especially useful if you have long running tasks so you can stop their execution on termination.

RequestData contains:

• The requests headers as string
• The method of the request
• The body of the request
• The query of attached to the url
• Functions to write to the response