2. Tutorials
  3. hapi — How to Register Plugins for a Selected Server Instance

hapi — How to Register Plugins for a Selected Server Instance

Within a previous tutorial, you’ve already seen how to separate the frontend and backend within a single hapi project. Hapi ships with build-in support to create multiple connections which are internally handled as virtual servers that listen on different ports.

Because you’re already using multiple internal servers, you want to keep them lean and only add the functionality that is required for the given instance. Further, it’s a best-practice in hapi to use plugins to add functionality to your server and you can apply that behavior across multiple servers as well.

This tutorial will walk you through the process on how to create multiple hapi server connections and register individual plugins only for a selected instance.

hapi Series Overview

  1. Get Your Server Up and Running
  2. v17 Upgrade Guide (Your Move to async/await)
  3. Become a Better Developer in 2018
  4. Become a Better Developer in 2017
  1. What You’ll Build
  2. Prepare Your Project: Stack & Structure
  3. Environment Variables and Storing Secrets
  4. Set Up MongoDB and Connect With Mongoose
  5. Sending Emails in Node.js
  6. Load the User’s Profile Picture From Gravatar Using Virtuals in Mongoose
  7. Implement a User Profile Editing Screen
  8. Generate a Username in Mongoose Middleware
  9. Displaying Seasons and Episodes for TV Shows with Mongoose Relationship Population
  10. Implementing Pagination for Movies
  11. Implement a Watchlist
  12. Create a Full Text Search with MongoDB
  1. Create a REST API with JSON Endpoints
  2. Update Mongoose Models for JSON Responses
  3. API Pagination for TV Shows
  4. Customize API Endpoints with Query Parameters
  5. Always Throw and Handle API Validation Errors
  6. Advanced API Validation With Custom Errors
  7. Create an API Documentation with Swagger
  8. Customize Your Swagger API Documentation URL
  9. Describe Endpoint Details in Your Swagger API Documentation
  10. 10 Tips on API Testing With Postman
  11. JWT Authentication in Swagger API Documentation
  12. API Versioning with Request Headers
  1. IP-Based Rate Limits (Part 1 of 7)
  2. Rate Limits for Routes (Part 2 of 7)
  3. Dynamic Rate Limits (Part 3 of 7)
  4. Render a “Rate Limit Exceeded” View (Part 4 of 7)
  5. Show “Rate Limit Exceeded” Error on Login (Part 5 of 7)
  6. Disable Rate Limiting (Part 6 of 7)
  7. Rate Limiter Refactoring & Cleanup (Part 7 of 7)
  1. API Login With Username and Password to Generate a JWT
  2. JWT Authentication and Private API Endpoints
  3. Refresh Tokens With JWT Authentication
  4. Create a JWT Utility
  5. JWT Refresh Token for Multiple Devices
  6. Check Refresh Token in Authentication Strategy
  7. Rate Limit Your Refresh Token API Endpoint
  8. How to Revoke a JWT
  9. Invalidate JWTs With Blacklists
  10. JWT Logout (Part 1/2)
  11. JWT “Immediate” Logout (Part 2/2)
  12. A Better Place to Invalidate Tokens
  13. How to Switch the JWT Signing Algorithm
  14. Roll Your Own Refresh Token Authentication Scheme
  15. JWT Claims 101
  16. Use JWT With Asymmetric Signatures (RS256 & Co.)
  17. Encrypt the JWT Payload (The Simple Way)
  18. Increase JWT Security Beyond the Signature
  19. Unsigned JSON Web Tokens (Unsecured JWS)
  20. JWK and JWKS Overview
  21. Provide a JWKS API Endpoint
  22. Create a JWK from a Shared Secret
  23. JWT Verification via JWKS API Endpoint
  24. What is JOSE in JWT
  25. Encrypt a JWT (the JWE Way)
  26. Authenticate Encrypted JWTs (JWE)
  27. Encrypted and Signed JWT (Nested JWT)
  28. Bringing Back JWT Decoding and Authentication
  29. Bringing Back JWT Claims in the JWT Payload
  1. How to Run Separate Frontend and Backend Servers Within a Single Project
  2. How to Use Server Labels
  3. How to Correctly Stop Your Server and Close Existing Connections
  1. Basic Authentication With Username and Password
  2. Authentication and Remember Me Using Cookies
  3. How to Set a Default Authentication Strategy
  4. Define Multiple Authentication Strategies for a Route
  5. Restrict User Access With Scopes
  6. Show „Insufficient Scope“ View for Routes With Restricted Access
  7. Access Restriction With Dynamic and Advanced Scopes
  8. hapi - How to Fix „unknown authentication strategy“
  9. Authenticate with GitHub And Remember the Login
  10. Authenticate with GitLab And Remember the User
  11. How to Combine Bell With Another Authentication Strategy
  12. Custom OAuth Bell Strategy to Connect With any Server
  13. Redirect to Previous Page After Login
  14. How to Implement a Complete Sign Up Flow With Email and Password
  15. How to Implement a Complete Login Flow
  16. Implement a Password-Reset Flow
  1. Views in hapi 9 (and above)
  2. How to Render and Reply Views
  3. How to Reply and Render Pug Views (Using Pug 2.0)
  4. How to Create a Dynamic Handlebars Layout Template
  5. Create and Use Handlebars Partial Views
  6. Create and Use Custom Handlebars Helpers
  7. Specify a Different Handlebars Layout for a Specific View
  8. How to Create Jade-Like Layout Blocks in Handlebars
  9. Use Vue.js Mustache Tags in Handlebars Templates
  10. How to Use Multiple Handlebars Layouts
  1. Route Handling and Drive Traffic to Your Server
  2. How to Serve Static Files (Images, JS, CSS, etc.)
  3. How to Use Query Parameters
  4. Optional Path Parameters
  5. Multi-Segment/Wildcard Path Parameters
  6. Ignore Trailing Slashes on Route Paths
  7. How to Fix “Unsupported Media Type”
  1. How to Access and Handle Request Payload
  2. Access Request Headers
  3. How to Manage Cookies and HTTP States Across Requests
  4. Detect and Get the Client IP Address
  5. How to Upload Files
  6. Quick Access to Logged In User in Route Handlers
  7. How to Fix “handler method did not return a value, a promise, or throw an error”
  8. How to Fix “X must return an error, a takeover response, or a continue signal”
  1. How to Reply a JSON Response
  2. How to Set Response Status Code
  3. How to Handle 404 Responses for Missing Routes
  1. Query Parameter Validation With Joi
  2. Path Parameter Validation With Joi
  3. Request Payload Validation With Joi
  4. Validate Query and Path Parameters, Payload and Headers All at Once on Your Routes
  5. Validate Request Headers With Joi
  6. Reply Custom View for Failed Validations
  7. Handle Failed Validations and Show Errors Details at Inputs
  8. How to Fix AssertionError, Cannot validate HEAD or GET requests
  1. Add CSRF Protection on Forms and API Endpoints
  1. Report Errors to Sentry
  2. Don’t Report Errors to Sentry in Development Mode
  3. Logging Fundamentals
  4. Log to Console With Good
  5. Log to File With Good
  1. Getting Started With Testing Using Lab and Code
  2. Run Tests with Assertions using Code
  3. Test Route Handlers by Injecting Requests
  4. Inject Request Payload, Headers and Parameters While Testing Route Handlers
  1. Zero-Downtime Deployments Using PM2

Multiple hapi Server Connections

As a hapi developer, you’re already familiar with the server.connection() method that defines the incoming server connection. As the return value of such method call, you’ll get a server object that is usable like you would do with new Hapi.Server(). When adding a second connection, you’ll receive another server instance in return. For those different server instances, you can register routes and plugins and call the same methods as you would do on the actual server object.

The following code example shows you how to create two connections: the first is labeled as frontend and the second one as backend. Later within this tutorial, we’ll refer to this code block with reference to it’s file name: server.js.

server.js

var Hapi = require('hapi')  
var _ = require('lodash')  
var port = 3000

// create new server instance
var server = new Hapi.Server()

// add server’s connection information
var frontend = server.connection({  
  host: 'localhost',
  port: process.env.PORT || port,
  labels: 'frontend'
})

// add another server connection
var backend = server.connection({  
  host: 'localhost',
  port: process.env.PORT + 1 || port + 1,
  labels: 'backend'
})

// start your server after plugin registration
server.start(function (err) {  
  if (err) {
    throw err
  }

  _.forEach(server.connections, function(connection) {
    console.log('Server started at: ' + connection.info.uri)
  })
})

The individual connections for frontend and backend use a port offset of 1 which means the backend is available on a port that is increased by one in reference to the frontend. Ultimately, you’re going to start both virtual servers for frontend and backend on their defined connections.

If you’re going to run the code snippet from above, the command line output will look like this:

$ node server.js
Server started at: http://localhost:3000  
Server started at: http://localhost:3001

Due to the fact that you didn’t specify the PORT environment variable while starting the server.js file, the default port 3000 is used for the frontend connection and port 3001 for the backend respectively.

Register Plugins Only for a Selected Server

The server setup is done. You’ve created two virtual server instances that can be used as two different servers with their individual functionality. Plugins are an essential component in hapi and it’s highly recommended to extend your server’s functionality using plugins.

In the following, you’ll create a simple plugin that registers a route to the calling server instance. Any further reference to this plugin is done via the chosen file name: frontend-routes.js.

frontend-route.js

var plugin = {  
  register: function (server, options, next) {
    server.route({
      method: 'GET',
      path: '/',
      handler: function (request, reply) {
        reply('Frontend is totally fine')
      }
    })

    next()
  }
}

plugin.register.attributes = {  
  name: 'multiple-server-instances-frontend-routes',
  version: '1.0.0'
}

module.exports = plugin

As you can see, the plugin code is straight forward and only adds the mentioned route to the server. Finally, the next() method gets called to notify hapi that the plugin was added correctly and the next one can be registered.

That plugin can now be used and registered to a selected server instance. Because your plugin is dedicated to the frontend, you only want to register it to the frontend server. Add the following lines to your server.js file (or your chosen file name) and with that register the plugin to your frontend instance.

frontend.register({  
  register: require('./frontend-route')
})

Restart your hapi server so that the changes take effect. The registered plugin adds the defined route to your frontend server which is available on port 3000 (or your chosen port). Just call http://localhost:3000 in your browser to check if everything went smooth. You should see the Frontend is totally fine message.

You can double check your backend by navigating to http://localhost:3001 in your browser and verify that the plugin wasn’t added to the backend server instance as well.

Outlook

This guide walked you through the setup of a hapi server that listens for incoming requests on two connections. Further, you’ve created a plugin and only registered it to one of the two server connections. That functionality allows you to separate concerns in your hapi app and also keeps a small footprint for your individual servers.

Do you have any question or just want to leave a message? Use the comments below or find us on Twitter @futurestud_io

Make it rock & enjoy coding!

Additional Resources

Marcus Pöhls

Marcus is a fullstack JS developer. He’s passionate about the hapi framework for Node.js and loves to build web apps and APIs. Creator of Futureflix and the “learn hapi” learning path.

Explore the Library

Find interesting tutorials and solutions for your problems.

Android

Node.js

Server

Miscellaneous