lambdasync/bin/test/handler-mock.js

Easy sync between local code and AWS lambda functions

const users = [{id: 1, name: 'Joe'}, {id: 2, name: 'Jane'}];

const defaultHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Content-Type': 'application/json'
};

function createProxyReturnObject(statusCode, body = null, headers = defaultHeaders) {
  return {
    statusCode,
    headers,
    body: JSON.stringify(body)
  };
}

function contextSucceed(event, context) {
  context.succeed(createProxyReturnObject(200, 'Everything is awesome!'));
};

function contextFail(event, context) {
  context.fail(createProxyReturnObject(404, 'Oops! Not found.'));
};

function contextDone(event, context) {
  context.done(createProxyReturnObject(500, {error: 'This test failed.'}));
};

function callback(event, context, callback) {
  callback(createProxyReturnObject(200, 'Everything is awesome!'));
};

function usersPostWithBody(event, context, callback) {
  if (event.httpMethod === 'POST' && event.path === '/users') {
    context.succeed(createProxyReturnObject(200, JSON.parse(event.body)));
  }
  return context.fail(createProxyReturnObject(500, {error: 'This test failed.'}));
};

function usersPatchWithBody(event, context, callback) {
  if (event.httpMethod === 'PATCH' && event.path === '/users/1') {
    context.succeed(createProxyReturnObject(200, JSON.parse(event.body)));
  }
  return context.fail(createProxyReturnObject(500, {error: 'This test failed.'}));
};

function usersDelete(event, context, callback) {
  if (event.httpMethod === 'DELETE' && event.path === '/users/1') {
    context.succeed(createProxyReturnObject(200));
  }
  return context.fail(createProxyReturnObject(500, {error: 'This test failed.'}));
};

function expressApp() {
  const awsServerlessExpress = require('aws-serverless-express');
  const express = require('express');
  const bodyParser = require('body-parser');
  const cors = require('cors');
  const awsServerlessExpressMiddleware = require('aws-serverless-express/middleware');

  const app = express();
  app.use(cors());
  app.use(bodyParser.json());
  app.use(bodyParser.urlencoded({extended: true}));
  app.use(awsServerlessExpressMiddleware.eventContext());

  // Ephemeral in-memory data store
  const users = [{id: 1, name: 'Joe'}, {id: 2, name: 'Jane'}];
  let userIdCounter = users.length;

  // User functions
  const getUser = userId => users.find(u => u.id === parseInt(userId, 10));
  const getUserIndex = userId => users.findIndex(u => u.id === parseInt(userId, 10));

  app.get('/', (req, res) => {
    res.sendFile(`${__dirname}/index.html`);
  });

  app.get('/users', (req, res) => {
    res.json(users);
  });

  app.get('/users/:userId', (req, res) => {
    const user = getUser(req.params.userId);
    if (!user) {
      return res.status(404).json({});
    }

    return res.json(user);
  });

  app.post('/users', (req, res) => {
    const user = {
      id: ++userIdCounter,
      name: req.body.name
    };
    users.push(user);
    res.status(201).json(user);
  });

  app.put('/users/:userId', (req, res) => {
    const user = getUser(req.params.userId);
    if (!user) {
      return res.status(404).json({});
    }

    user.name = req.body.name;
    res.json(user);
  });

  app.delete('/users/:userId', (req, res) => {
    const userIndex = getUserIndex(req.params.userId);
    if (userIndex === -1) {
      return res.status(404).json({});
    }

    users.splice(userIndex, 1);
    res.json(users);
  });

  const server = awsServerlessExpress.createServer(app);

  return (event, context) => awsServerlessExpress.proxy(server, event, context);
}

exports = module.exports = {};
exports.createProxyReturnObject = createProxyReturnObject;
exports.contextSucceed = contextSucceed;
exports.contextFail = contextFail;
exports.contextDone = contextDone;
exports.callback = callback;
exports.usersPostWithBody = usersPostWithBody;
exports.usersPatchWithBody = usersPatchWithBody;
exports.usersDelete = usersDelete;
exports.expressApp = expressApp;