retes

Retes

Typed, Declarative, Data-Driven Routing for Node.js.

What is Retes?

Retes is a routing library for Node.js written in TypeScript and inspired by Clojure's Ring, Compojure and Retit. It is built directly on top of the Node.js http module, so you can use it as an alternative to Express or Koa.

• Data-Driven: In Retes you define routes using the existing data structures. This way, we limit the number of abstractions and we are able to easily transform and combine routes. Our routing description is declarative.
• Typed: The type system conveniently helps us control the shape of our routing
• Battery-Included (wip): Most common middlewares will be included out of the box

Key Features

• built-in parsing of query params, body and route's dynamic segments
• built-in file uploading handling mechansim
• fast route matching (see Benchmarks)
• handlers are functions that take requests as input and return responses as output
• middlewares can be combined on per-route basis
• an HTTP response is just an object containing at least statusCode and body keys

Why Retes?

• declarative route descriptions make them easily composable
• functional handlers are more natural fit for the HTTP flow
• common request/response transformations are already built-in
• typed routes make it easier to discover and control the shape of data flowing in and out

Usage

Generate a new Node.js project

mkdir my-api
cd my-api
npm init -y

Add retes as a dependency

npm i retes

Create tsconfig.json with the following content:

{
  "compilerOptions": {
    "lib": [ "es2015", "DOM" ]
  }
}

Create app.ts with the following content:

import { Route, ServerApp, Response } from 'retes';

const { GET, POST } = Route;
const { Created } = Response;

const routes = [
  GET("/", () => "Hello, World"),
  GET("/welcome/:name", ({ params }) => {
    return { statusCode: 200, body: `Hello, ${params.name}` }
  }),
  POST("/user", ({ params: { name } }) => `Received: '${name}'`),
  POST("/widget", ({ params: { name, count } }) => {
    // validate `params`
    // save the widget to database ...
    return Created() // returns `201 Created` response
  })
]

async function main() {
  const app = new ServerApp(routes);
  await app.start(3000);

  console.log('started')
}

main()

Save it to a file, e.g. app.ts and run using ts-node

Install ts-node globally

npm i -g ts-node

Run the application

ts-node app.ts

The server application listens on the specified port, in our case :3000. Open localhost:3000 and test the routes.

Features

Params

Retes combines requests' query params, body params and segment params into params.

import { Route, ServerApp, Response } from 'retes';

const { GET, POST } = Route;
const { OK } = Response;

const routes = [
  GET("/query-params", ({ params }) => OK(params)),
  POST("/body-form", ({ params }) => OK(params)),
  POST("/body-json", () => OK(params)),
  GET("/segment/:a/:b", ({ params }) => OK(params)),
]

async function main() {
  const app = new ServerApp(routes);
  await app.start(3000);

  console.log('started')
}

main()

This GET query

http :3000/query-params?a=1&b=2

returns

HTTP/1.1 200 OK

{
    "a": "1",
    "b": "2"
}

This POST query with Content-Type set to application/x-www-form-urlencoded; charset=utf-8

http --form :3000/body-form a:=1 b:=2

returns

HTTP/1.1 200 OK

{
    "a": "1",
    "b": "2"
}

This POST query with Content-Type set to application/json

http :3000/body-json a:=1 b:=2

returns

HTTP/1.1 200 OK

{
    "a": 1,
    "b": 2
}

This GET request

http :3000/segment/1/2

returns

HTTP/1.1 200 OK
{
    "a": "1",
    "b": "2"
}

Convenience Wrappers for HTTP Responses

import { Route, ServerApp, Response } from 'retes';

const { GET } = Route;
const { Created, OK, Accepted, InternalServerError } = Response;

const routes = [
  GET("/created", () => Created("payload")), // returns HTTP 201 Created
  GET("/ok", () => OK("payload")), // returns HTTP 200 OK
  GET("/accepted", () => Accepted("payload")), // returns HTTP 202 Accepted
  GET("/internal-error", () => InternalServerError()), // returns HTTP 500 Internal Server Error
]

async function main() {
  const app = new ServerApp(routes);
  await app.start(3000);

  console.log('started')
}

main()

Middleware Composition on Per-Route Basis

import { Route, ServerApp } from 'retes';

const { GET } = Route;

const prepend = next => request => `prepend - ${next()}`;
const append = next => request => `${next()} - append`

const routes = [
  GET("/middleware", () => "Hello, Middlewares", {
    middleware: [prepend, append]
  }) // equivalent to: prepend(append(handler))
]

async function main() {
  const app = new ServerApp(routes);
  await app.start(3000);

  console.log('started')
}

main()

Declarative Validation

Retes comes with a built-in validation middleware. It's a higher-order functions that checks the request parameters against a Zod schema. Note that request parameters combine query params, body params and segment params into a single values available as params.

import { Route, ServerApp, Middleware } from 'retes';
import * as z from 'zod';

const { GET } = Route;

const schema = z.object({
  name: z.string()
});

const routes = [
  GET('/request-validation', ({ params }) => {
    return `The request for this handler is validated using the given schema`,
  }, { middleware: [ Middleware.Validation(schema) ] }))
]

async function main() {
  const app = new ServerApp(routes);
  await app.start(3000);

  console.log('started')
}

main()

Benchmarks

WIP

Roadmap

• infer types for dynamic segments from routes using the string literals feature from TypeScript 4.1 (in progress PR #1)