Create Express Application

Create a directory to save express project

   $ mkdir ~/projects/express_app
   $ cd ~/projects/express_app

Run the following command to create a new NodeJS projet

    npm init

This command will asks you to enter the application name and many other information. Just click enter. When finished process, It show you an folder structure like this.

Installing express

Now, it´s time to install express library in your project

    npm install express --save

Starting to code

Create an app.js file in your root directory

    $touch app.js

Copy and paste the following code inside the app.js file

    const express = require('express')
    const app = express()
    app.use(express.json())

    app.get('/', (req, res) => res.send('Hello world!'))

    const port = process.env.PORT || 3011

    app.listen(port, () => 
    console.log(`App is listening on port ${port}.`)
    )

Creating more endpoints in express

    app.get('/:name', function(req, res){
        res.send('Req params: ' + req.params.name);
    });

    app.post('/:name', function (req, res) {
        res.send('Got a POST request' + JSON.stringify(req.body));
    });

    app.put('/:name', function (req, res) {
        res.send('Got a PUT request');
    });

    app.delete('/:name', function (req, res) {
        res.send('Got a DELETE request');
    });

Run node app in local mode

Now, You can run this file with the following command

   $ node app.js

Examples and documentation

Setting a node-express application to run in AWS Lambda

In order to use Claudia.js to deploy on AWS Lambda, you need slightly to modify the code in app.js. Instead of staring the server using app.listen, you should export your app. After these modification, your app.js file should look like the following:

    const express = require('express')
    const app = express()

    app.get('/', (req, res) => res.send('Hello world!'))

    module.exports = app;

Creating another file called app.local.js with the following content:

    const app = require('./app')
    const port = process.env.PORT || 3000

    app.listen(port, () => 
    console.log(`App is listening on port ${port}.`)
    )

Well done, Now we have a very basic project based on node and express

Run Node and Express in AWS Lambda

In this part we need to install Claudia.js. It makes super simple to deploy Node.js apps on AWS Lambda and API Gateway Install Claudia.js library

    $ npm install -g claudia

You need to generate AWS Lambda wrapper for your Express app to make that your app work correctly on AWS Lambda. Using Claudia, you can do so by running the following command:

    $ claudia generate-serverless-express-proxy --express-module app

app is the name of your main file app.js Above command will generate a lambda.js file in your app root directory with the following content:

    'use strict'
    const awsServerlessExpress = require('aws-serverless-express')
    const app = require('./index')
    const binaryMimeTypes = [
        'application/octet-stream',
        'font/eot',
        'font/opentype',
        'font/otf',
        'image/jpeg',
        'image/png',
        'image/svg+xml'
    ]
    const server = awsServerlessExpress.createServer(app, null, binaryMimeTypes);
    exports.handler = (event, context) => awsServerlessExpress.proxy(server, event, context)

That's it. Now you just need to deploy your Express app (with lambda.js file) to AWS Lambda and API Gateway using the the command:

    $ claudia create --handler lambda.handler --deploy-proxy-api --region us-east-1

If everything goes well, the above command will finish after a few moments and will print the following response:

    {
    "lambda": {
        "role": "express-app-executor",
        "name": "express-app",
        "region": "us-east-1"
    },
    "api": {
        "id": "2yfnh84gcj",
        "url": "https://joxpcjx0j4.execute-api.us-east-1.amazonaws.com/latest"
    }
    }

In future, if you want to change your app code (i.e. add more routes), you can deploy those changes to AWS Lambda with the following command:

    $ claudia update

Examples

Create a module to export some function or function like a class

app.js file

   const express = require('express')
   const app = express()
   var person = require('./functionName')
   app.use(express.json())
   app.get('/', (req, res) => res.send('Hello world!'));

   app.post('/:name', function (req, res) {
       var person1 = new person('James', 'Bond');
       console.log(person1.fullName());
       res.send('Got a POST request' + JSON.stringify(req.body));
   });

   const port = process.env.PORT || 3011
   app.listen(port, () => console.log(`App is listening on port ${port}.`))

functionName.js file

   module.exports = function(firstName, lastName) {
       this.firstName = firstName;
       this.lastName = lastName;
       this.fullName = function () { 
           return this.firstName + ' ' + this.lastName;
       }
   }

BruceRIP/social-login-lambda