Iworb's blog

Full Stack (Node + Express + MongoDb + Vue + Nuxt) application. Part 2: Helpers, Configs and Session

2018-02-13

Helpers

Helpers will land in server/helpers directory, so add an alias in package.json for it:

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"@helpers": "./server/helpers"

Environment

Let’s add env.js helper which checks our environment:

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module.exports = {
  isDev () {
    return !process.env.NODE_ENV || process.env.NODE_ENV === 'development'
  },

  isProduction () {
    return process.env.NODE_ENV === 'production'
  },

  isTest () {
    return process.env.NODE_ENV === 'test'
  }
}

To export this module in easy way lets make an index for helpers:

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const env = require('./env')

module.exports = {
  env
}

Token generator

Another one nifty helper intended for token generation for secrets.

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yarn add uuid-token-generator

tokgen.js:

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let TokenGenerator = require('uuid-token-generator')
let tokgen = new TokenGenerator(256, TokenGenerator.BASE62)

module.exports = function () {
  return tokgen.generate()
}

And extend index file for this new helper:

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const env = require('./env')
const tokgen = require('./tokgen')

module.exports = {
  env,
  tokgen
}

Configs

Config should be flexible, so we have to merge it into separate files:

  • base.js - basic configuration which should be a skeleton of config;
  • config.template.js - template for config.js file, which could be used to set your own secrets. It is excluded from git, so we need a template to create new one if there’s new instance;
  • dev.js, prod.js and test.js - confings based on environment;
  • index.js - summary config.
    Let’s init them with following code:
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    module.exports = {}

As an example let’s make a session config.
base.js:

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module.exports = {
  session: {
    resave: true,
    saveUninitialized: false,
    cookie: {
      // reset session after 1 week
      maxAge: 7 * 24 * (60 * 60 * 1000),
      // we will use cookies just for HTTP, not js
      // JS will send this cookies only from current domain
      httpOnly: true,
      // should be 'true' if you're using https
      secure: false
    }
  }
}

Now we have almost complete session config but secret. Each user have to define his own session, so lets make our template which will generate secret for a session if there’s no config.js file.
config.template.js:

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module.exports = {
  session: {
    secret: '{{sessionSecret}}',
    resave: true,
    saveUninitialized: false,
    cookie: {
      // reset session after 1 week
      maxAge: 7 * 24 * (60 * 60 * 1000),
      // we will use cookies just for HTTP, not js
      // JS will send this cookies only from current domain
      httpOnly: true,
      // should be 'true' if you're using https
      secure: false
    }
  }
}

and another stuff in double braces will be replaced with provided data.
To improve console logging and js functionality I gonna include this modules into project:

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yarn add chalk lodash

There’s how index.js file looks:

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const path = require('path')
const fs = require('fs')
const _ = require('lodash')
const chalk = require('chalk')
const {tokgen, env} = require('@helpers')

let config = {}

try {
  // [1]
  if (!fs.existsSync(path.join(__dirname, 'config.js'))) {
    console.warn(chalk.yellow.bold('`config.js` for server settings was not found! Generating new `config.js` file'))
    const template = fs.readFileSync(path.join(__dirname, 'config.template.js'))
    _.templateSettings.interpolate = /{{([\s\S]+?)}}/g
    const compiled = _.template(template)
    const replacements = {
      sessionSecret: tokgen()
    }
    fs.writeFileSync(path.join(__dirname, 'config.js'), compiled(replacements))
    console.warn(chalk.green.bold('New `config.js` for server settings file was generated. You could update your settings here: "server/config/config.js"'))
  }
  config = require('./config')
} catch (error) {
  console.warn(chalk.red.bold('\r\n=============================================='))
  console.warn(chalk.red.bold('  Unable to load external `config.js` file!'))
  console.warn(chalk.red.bold(' ', error))
  console.warn(chalk.red.bold('==============================================\r\n'))
  process.exit(1)
}

// [2]
let envConfig = {}

if (env.isDev()) {
  envConfig = require('./dev')
} else if (env.isTest()) {
  envConfig = require('./test')
} else if (env.isProduction()) {
  envConfig = require('./prod')
}

// [3]
const base = require('./base')

module.exports = _.defaultsDeep(envConfig, config, base)

First of all we have to check is there config.js [1] file exists. If no we’re reading our config.template.js and replace template variables with generated values and make config.js.
Next [2] we’re reading environment-based config and [3] base one, than return merged config.
Last thing is module alias for config folder:

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"@config": "./server/config"

Session

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yarn add express-session cookie-parser body-parser

Add using of session in our application lets extend server/index.js file:

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require('module-alias/register')
const config = require('@config')
const express = require('express')
const session = require('express-session')
const bodyParser = require('body-parser')
const cookieParser = require('cookie-parser')
const app = express()

const configSession = config.session
app.use(bodyParser.urlencoded({
  extended: true
}))
app.use(bodyParser.json())
app.use(cookieParser())
app.use(session(configSession))

const {Nuxt, Builder} = require('nuxt')
...

This part wraps up 02-helpers-config-session git branch.

Tags: express
← Full Stack (Node + Express + MongoDb + Vue + Nuxt) application. Part 2: Nuxt and Expres Full Stack (Node + Express + MongoDb + Vue + Nuxt) application. Part 3: Logging, initialization splitting and more helpers →