Nokkel API Library

A library for create Node, Koa-based applications. It facilitates both HTTP server and serverless exports of your APIs.

Using this library

In order to use this library you should first create your application using the factory function. (This example uses the config library):

index.ts

import { application } from './app';
import configuration from 'config';

// Start the server
const config = configuration.util.toObject();
try {
  application.start({ port: config.app.port });
} catch (err) {
  application.end();
}

// Or you can export as a serverless handler instead with one of the below examples - simple!
// AWS - Lambda
// export const handler = application.serverless({ provider: 'aws' });

// Azure - Function
// export const nameOfFunction = application.serverless({ provider: 'azure' });

// Google Cloud - Cloud Function
// application.serverless({ provider: 'gcloud' });

app.ts

import { createApplication, generateSwaggerSpec } from '@nokkel/api';
import configuration from 'config';

import { AccountService, CoffeeService } from './lib/services';
import { accountRouteFactory, coffeeRouteFactory } from './routes';

const config = configuration.util.toObject();
export const application = createApplication({
  config: {
    name: config.app.name,
    logLevel: config.log.level,
    // This attaches services to the request context, accessible in a middleware via `ctx.services`
    services: {
      account: new AccountService(),
      coffee: new CoffeeService(),
    },
  },
  cors: { origin: config.cors.origin },
  // Specify koa options constructor
  koa: {},
  // Specify options for koa-body
  body: {},
  swagger: {
    spec: generateSwaggerSpec({
      definition: {
        info: {
          title: config.app.name,
          version: config.app.version,
        },
      },
    }),
  },
});

application.use(accountRouteFactory().attach());
application.use(coffeeRouteFactory().attach());

lib/services.ts

export class AccountService {
  public async retrieveAccounts() {
    return fetch('https://api.sampleapis.com/fakebank/accounts').then(res =>
      res.json()
    );
  }
}

export class CoffeeService {
  public async retrieveCoffee(type: 'hot' | 'iced') {
    return await fetch(
      new URL(`https://api.sampleapis.com/coffee/${type}`)
    ).then(res => res.json());
  }
}

middlewares.ts

import type { AccountService, CoffeeService } from '../lib';

interface Account {
  transactionDate: string;
  description: string;
  category: string;
  debit: number | null;
  credit: number | null;
  id: number;
}

export function accountMiddlewareFactory(): Middleware<
  Account[],
  { account: AccountService }
> {
  return async function accountMiddleware(ctx) {
    ctx.body = await ctx.services.account.retrieveAccounts();
    ctx.status = 200;
  };
}

interface Coffee {
  title: string;
  description: string;
  ingredients: string[];
  image: string;
  id: number;
}

export function coffeeMiddlewareFactory(): Middleware<
  Coffee,
  { coffee: CoffeeService }
> {
  return async function exampleMiddleware(ctx) {
    const type = ctx.params.type as 'hot' | 'iced';
    ctx.body = await ctx.services.coffee.retrieveCoffee(type);
    ctx.status = 200;
  };
}

routes.ts

import { Router, schemaMiddlewareFactory } from '@nokkel/api';

import {
  accountMiddlewareFactory,
  coffeeMiddlewareFactory,
} from '../middlewares';

/**
 * @openapi
 * /accounts:
 *  get:
 *    tags:
 *      - Account
 *    description: Retrieve bank accounts
 *    responses:
 *      200:
 *        description: Return 200 response
 *        content:
 *          application/json:
 *            schema:
 *              type: array
 */
export function accountRouteFactory() {
  const router = new Router();
  router.get('accounts', '/accounts', accountMiddlewareFactory());
  return router;
}

/**
 * @openapi
 * /coffee/{type}:
 *  post:
 *    tags:
 *      - Coffee
 *    description: Retrieve types of coffee
 *    parameters:
 *      - name: type
 *        in: path
 *        description: The type of coffee you want to retrieve
 *        required: true
 *        schema:
 *          type: string
 *          enum:
 *            - hot
 *            - iced
 *    responses:
 *      200:
 *        description: Return 200 response
 *        content:
 *          application/json:
 *            schema:
 *              type: array
 */
export function coffeeRouteFactory() {
  const router = new Router();
  router.post(
    'coffee',
    '/coffee/:type',
    schemaMiddlewareFactory({
      schema: {
        path: {
          type: 'object',
          properties: {
            type: {
              type: 'string',
              enum: ['hot', 'iced'],
            },
          },
          required: ['type'],
        },
      },
      expose: true,
    }),
    coffeeMiddlewareFactory()
  );
  return router;
}

Enjoy!