Decade ☄️

Dead simple HTTP/s Server Wrapper with zero dependencies written with Typescript in about 200 lines.

This library encourages users to work with built in Node modules and the built in Router only supports two Http verbs, GET and POST, because the other ones are trash.

Install

Install with yarn.

yarn add decade

Usage

Create a http and https server.

import { Server } from "decade";

const server = new Server({
  http: 3080,
  https: 3443,
  options: {
    key: "...",
    cert: "...",
  },
});

Plugin

Decade provides a simple Plugin system, a plugin should be something with a register method which will receive the Server instance and a Logger instance, from there you can listen for and emit events.

import { Server, Logger } from "decade";
export class MyPlugin implements Server.Plugin {
  ...
  async register(server: Server, logger: Logger): Promise<void> {
    this.server = server;
    this.logger = logger;
    server.on("request", this.doSomething.bind(this));
  }

  async someOtherMethod() {
    this.logger.info("something happened!");
    this.server.emit("customevent", "foo");
  }
}

To use a plugin, pass it into the Server.plugin method.

import { Server } from "decade";
import { FooPlugin } from "decade-foo-plugin";

const server = new Server({...});
server.plugin(new FooPlugin("bar"));

Router

There's a built in Router plugin available for import which can be initialized with an array of Router.Route objects.

import { Server, Router } from "decade";
import * as routes from "./routes";

const server = new Server({...})

const router = new Router(Object.values(routes));

server.plugin(router);

For simple JSON responses you can return a Router.Route.Payload object from a handler which will be parsed and sent to the client.

import { Router } from "decade";

export const simpleRoute: Router.Route = {
  path: /^\/[a-z]+$/,
  method: "GET",
  handler: [
    async () => {
      return {
        status: 200,
        headers: {
          "Foo-Bar": "Baz-Qak",
        },
        body: {
          foo: "bar",
        },
      };
    },
  ]
}

If you need more control, you can craft your own response and simply return void from the handler - handlers are called in-order so you can drop in middleware wherever suits.

import { Router } from "decade";
import { fooMiddleware } from "./middleware"

export const detailedRoute: Router.Route = {
  path: /^\/proxy$/,
  method: "GET",
  handler: [
    fooMiddleware,
    async (request, response) => {
      https.get('https://www.example.com', (proxy) => {
        response.setHeader('Content-Type', proxy.headers['content-type']);
        proxy.pipe(response);
      });
    },
  ]
}

Routes resolve sequentially so if you have multiple routes which match the request URL they will all be called in the order that they were added to the Router.

A common oversight is resolving routes too early, like the proxy route above which resolves immediately. Routes should only resolve once they are finished interacting with the request and response objects.

Middleware

By default incoming request objects aren't parsed for JSON or URL Encoded payloads but you can use built in Middleware to do this.

json

import { Server, Router } from "decade";

export const jsonRoute: Router.Route = {
  ...
  handler: [
    Server.Middleware.json,
    ...
  ]
}

urlencoded

import { Server, Router } from "decade";

export const jsonRoute: Router.Route = {
  ...
  handler: [
    Server.Middleware.urlencoded,
    ...
  ]
}

If you need support for Multipart form data or anything else you can write your own middleware or use a fully featured library like body-parser.

Examples

404 Not Found

There is no built in helper to detect that no routes match the request, however when a request is received all matching routes will be called in order of instantiation so you can craft your own 404 handler by adding a "catch all" path /.*/ as the last route.

export const notFoundRoute: Router.Route = {
  path: /.*/,
  method: "GET",
  handler: [
    async (request, response) => {
      if(response.headersSent) {
        return
      }

      return {
        status: 404,
        body: "Not Found",
      };
    },
  ],
}

Cookies

If you're adventurous you can bake your own cookies but it's recommended to use a library like cookie, afterwards you can set them as usual.

import * as cookie from "cookie";

export const cookieRoute: Router.Route = {
  ...
  handler: [
    async (request, response) => {
      return {
        status: 200,
        headers: {
          "Set-Cookie": "foo=bar",
          // or
          "Set-Cookie": cookie.serialize("foo", "bar", {...}),
        },
        body: "Cookies!",
      };
    },
  ],
}

Outgoing Transformations

It's pretty common practice to log or tag requests as they head back to the client, as an example let's create a middleware that adds a timestamp header to responses - if you're using the "simple" method of returning a Router.Route.Payload it is passed along to future middlewares as the third argument.

You can do this in two ways, the first by using the http.ServerResponse object and the setHeader() method, the second by mutating the Router.Route.Payload object's headers property.

export const timestampMiddleware: Router.Route.Handler = async (request, response, payload) => {
  response.setHeader("timestamp", new Date().getTime().toString());

  return payload;

  // or

  payload.headers = {
    ...payload.headers,
    timestamp: new Date().getTime().toString(),
  }

  return payload;
}

export const transformedRoute: Router.Route = {
  ...
  handler: [
    async () => {
      return {
        ...
      };
    },
    timestampMiddleware,
  ],
}