@techjs/create-http

TechJS | create-http

A utility for setting up @techjs/http projects.

Usage

npm init @techjs/http <dir>

Table of Contents

• Table of Contents
• Installation
  • System Dependencies
• About
• Getting Started (UNIX)
• Developing
  • Adding a new service
  • Adding a new controller
  • Registering the controller with the routes
  • Accessing our new route

Installation

Run the @techjs/http generator to get started.

npm init @techjs/http <dir>

System Dependencies

• NodeJS
• npm

About

The TechJS framework aims to provide a structured input event listener pattern by enforcing the principle of separation of concerns. The result is a clearly defined routes, controllers, and services. Through the power of object oriented programming, the @techjs/core library can be extended to provide a familiar interface between HTTP events and other application-layer input protocols, like event bus messages.

Warning

This example requires a bash environment. Using Bash on Windows or a console emulator like cmder should be fine. Alternatively, you can edit the npm scripts in the package.json file to work in your environment.

Developing

You will likely want more then just a ping server. Let's add a hashing service together to familiarize ourselves with creating new controllers, services, and routes. Once we are done, we will have a new route that will accept a url encoded string to hash given an algorithm specified in the URL path.

Adding a new service

// src/services/hash-service.ts

import * as crypto from 'crypto';

export class HashService {
  public async hash(algo: string, data: string | Buffer): Promise<string> {
    return new Promise<string>(
      (resolve, reject) => {
        const hash = crypto.createHash(algo);
        hash.on('readable', () => {
          const data: Buffer = <Buffer>hash.read();
          if (data) {
            resolve(data.toString('hex'));
          }
        });
        hash.on('error', (error) => {
          reject(error);
        });
        hash.write(data);
        hash.end();
      },
    );
  }
}

Note

We will want to export this serice from the src/services/ directory by adding an export statement in the src/services/index.ts file.

Adding a new controller

// src/controllers/hash.controller.ts

import { HttpController } from '@techjs/http';
import { Resolve } from 'tsnode-di';
import { HashService } from '../services';

export class HashController extends HttpController {
  @Resolve(HashService)
  private hash_service!: HashService;
  public async hash(): Promise<void> {
    try {
      const algo: string = this.req.params.algo;
      const data: string = this.req.query.data;
      const response: string = await this.hash_service.hash(algo, data);
      this.res.send(response);
    } catch (e) {
      this.res.sendStatus(500);
    }
  }
}

Note

We will want to export this controller from the src/controllers/ directory by adding an export statement in the src/controllers/index.ts file.

Registering the controller with the routes

// src/routes.ts

import { HttpRoute } from '@techjs/http';

// controllers

import {
  HashController,
  PingController,
} from './controllers/';

// routes

export const routes: Array<HttpRoute<any>> = [
  new HttpRoute('/ping', 'get', PingController, 'ping'),
  new HttpRoute('/hash/:algo', 'get', HashController, 'hash'),
];

Accessing our new route

We are now ready to run our server. We should have exposed a route at /hash/:algo. The HashController will hash any string passed to the data query parameter. Let's see what some requests look like

$ curl -G -X GET http://localhost:3000/hash/md5 --data-urlencod 'data=hello world'
5eb63bbbe01eeed093cb22bb8f5acdc3
$ curl -G -X GET http://localhost:3000/hash/sha256 --data-urlencod 'data=hello world'
b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9
$ curl -G -X GET http://localhost:3000/hash/foo --data-urlencod 'data=hello world'
Internal Server Error