Building Real-time Apps with Next.js 13.4 Server Actions

Hello there! If you're anything like me, you've probably found yourself marveling at the seamless interactivity of today's real-time web applications—those chatbots that respond instantly, the live notifications that pop up without a page refresh, and collaborative tools that update in the blink of an eye. Real-time functionality has become less of a luxury and more of an expectation in the digital age. Now, if you've been tracking the developments in the world of Next.js, you might've caught wind of the buzzworthy features of version 13.4, especially the game-changer: server actions. Are you curious about how this can redefine the way we craft real-time experiences? Well, so was I! Dive with me into this case study, where we'll embark on a journey to construct a real-time application, leveraging the power and finesse of server actions. Whether you're a seasoned developer or just venturing into the realm of real-time apps, there's a trove of insights waiting for you. Next.js Let’s get the ball rolling, shall we? Table of Contents Background: Understanding Real-time Applications What’s New in Next.js 13.4: A Glimpse at Server Actions Setting the Stage: Our Real-time Project Scope Getting Started: Initial Setup Building the Backend: Leveraging Server Actions Designing the Frontend: A Seamless User Experience Testing the Real-time Capabilities Enhancements and Optimizations Conclusion and Future Prospects Resources and Further Reading 1. Background: Understanding Real-time Applications In today's fast-paced digital landscape, the term "real-time" often pops up across various contexts—from gaming and finance to communication and social media. But what exactly does "real-time" mean in the world of web applications? Let's demystify this. What are Real-time Applications? Real-time applications are systems or programs that immediately respond to user inputs or external events, offering instant feedback without perceptible delays. In simpler terms, think of them as live, dynamic platforms that evolve in "real-time," mirroring the constant flow of information in the modern digital ecosystem. Real-life Examples To put it into perspective, consider some ubiquitous examples: : Platforms like and Telegram where messages are sent, received, and seen without delay. Instant Messaging Apps WhatsApp : Think of Google Docs, where multiple users can edit a document simultaneously, observing each other's changes in real-time. Collaborative Tools : Platforms that display stock prices that update instantaneously with market fluctuations. Live Stock Tickers : Where players interact with each other and the environment with zero latency, ensuring a seamless gaming experience. Online Multiplayer Games The Relevance of Real-time Applications So, why is real-time functionality so sought after? : Modern users expect immediacy. Whether it's a chat application or a weather update, any noticeable lag can lead to decreased user satisfaction. User Expectation : Real-time features enable a more interactive and immersive user experience, promoting user engagement. Enhanced Interactivity : Offering real-time features can set platforms apart in a crowded market, offering a unique selling point that attracts and retains users. Competitive Advantage The Challenges Ahead Building real-time applications is not without its hurdles: : Real-time apps often need to handle numerous simultaneous connections, requiring robust infrastructure. Scalability Issues : Ensuring that real-time data remains consistent across various user interfaces can be a challenge, especially with multiple simultaneous edits or interactions. Data Integrity : A real-time app is only as good as its slowest component. Ensuring minimal delays requires careful optimization and efficient use of resources. Latency Now that we've set the stage with a foundational understanding of real-time applications, we'll delve into how Next.js 13.4, with its server actions, emerges as a pivotal tool for developers aspiring to craft such immersive experiences. 2. What’s New in Next.js 13.4: A Glimpse at Server Actions In the ever-evolving landscape of web development, Next.js has consistently been at the forefront, introducing features that redefine how we approach building applications. Version 13.4 is no exception, particularly with its emphasis on server actions. But before we dive deep, let's clarify some terminology: A Primer on Actions in the React ecosystem, although still experimental, have brought about a paradigm shift by allowing developers to execute asynchronous code in response to user interactions. Actions Interestingly, while they aren't exclusive to Next.js or Server Components, their use through Next.js means you're on the React experimental channel. React For those familiar with HTML forms, you might recall passing URLs to the prop. Now, with Actions, you can directly pass a function, making interactions more dynamic and integrated. action { /* async function logic here */ }}>Click me! React's integration with Actions also offers built-in solutions for optimistic updates. This emphasizes that while Actions are groundbreaking, the patterns are still evolving, and newer APIs might be added to further enrich them. Embracing Form Actions represent an ingenious amalgamation of React's Actions with the standard API. They resonate with the primitive attribute in HTML, making it possible for developers to enhance progressive loading states and other functionalities out-of-the-box. Form Actions formaction

Server Functions & Server Actions are essentially functions that operate on the server-side but can be invoked from the client. These elevate Next.js's server-side rendering capabilities to a whole new level. Server Functions Transitioning to , they can be understood as Server Functions, but ones specifically triggered as an action. Their integration with form elements, especially through the prop, ensures that the form remains interactive even before the client-side JavaScript loads. This translates to a smoother user experience, with React hydration not being a prerequisite for form submission. Server Actions action // A simple Server Action in Next.js 13.4 Understanding Server Mutations Lastly, we have , which are a subset of Server Actions. These are particularly powerful when you need to modify data on the server and then execute specific responses, such as , , or . Server Mutations redirect revalidatePath revalidateTag const serverMutationFunction = async () => { // Modify data logic here... // ... return { revalidatePath: '/updated-path' }; }

In summary, Next.js 13.4's Server Actions framework, underpinned by Actions, Form Actions, Server Functions, and Server Mutations, embodies a transformative approach to real-time web applications. Notes: As we move forward in our case study, you'll witness firsthand the prowess these features bring to the table. So, let's gear up for the exciting journey ahead! 3. Setting the Stage: Our Real-time Project Scope In the context of building a real-time application, Next.js 13.4's Server Actions play a crucial role. These alpha features make it easy to manage server-side data mutations, reduce client-side JavaScript, and progressively enhance forms. Enabling Server Actions First, you'll need to enable Server Actions in your Next.js project. Simply add the following code to your file: next.config.js module.exports = { experimental: { serverActions: true, }, } Creation and Invocation Server Actions can be defined either within the Server Component that uses it or in a separate file for reusability between Client and Server Components. Here’s how you can create and invoke Server Actions: : A Server Action can be easily defined within a Server Component, like this: Within Server Components export default function ServerComponent() { async function myAction() { 'use server' // ... } } : When using a Server Action inside a Client Component, create the action in a separate file and then import it. With Client Components // app/actions.js 'use server' export async function myAction() { // ... } Importing and using in Client Component: // app/client-component.js import { myAction } from './actions'

export default function ClientComponent() { return ( Add to Cart ) } : You can use custom methods like to invoke Server Actions outside of forms, buttons, or inputs. Custom Invocation startTransition // Example using startTransition 'use client' import { useTransition } from 'react' import { addItem } from '../actions'

function ExampleClientComponent({ id }) { let [isPending, startTransition] = useTransition()

return ( startTransition(() => addItem(id))}> Add To Cart ) } Progressive Enhancement Next.js 13.4 also offers Progressive Enhancement, allowing a to function without JavaScript. Server Actions can be passed directly to a , making the form interactive even if JavaScript is disabled. // app/components/example-client-component.js 'use client' import { handleSubmit } from './actions.js'

export default function ExampleClientComponent({ myAction }) { return ( {/* ... */} ) } Size Limitation The maximum request body sent to a Server Action is 1MB by default. If needed, you can configure this limit using the option: serverActionsBodySizeLimit module.exports = { experimental: { serverActions: true, serverActionsBodySizeLimit: '2mb', }, } 4. Getting Started: Initial Setup Creating a new Next.js 13.4 project To get started with building a real-time application using Next.js 13.4, the first step is to create a new project. You can use the standard Next.js CLI command to initialize your project: npx create-next-app@latest my-real-time-app Replace with the desired name for your project. This command sets up a new Next.js project with default configurations. my-real-time-app Required dependencies and packages for real-time functionality For real-time functionality, there are certain packages and dependencies you may require. Depending on the specifics of your application, these could range from WebSockets libraries to GraphQL subscriptions and more. Ensure you've reviewed the project requirements and added the necessary dependencies. However, with Next.js 13.4's support for Server Actions, there's already a built-in setup that supports server-side processing, which can assist in achieving some of the real-time features. A brief overview of the project structure and directory setup The App Router With the introduction of Next.js 13.4, the is a significant feature that allows developers to utilize shared layouts, nested routing, error handling, and more. It's designed to work in conjunction with the existing directory, but it's housed within a new directory named . App Router pages app To get started with the App Router: Create an directory in the root of your project. app Add your routes or components inside this directory. By default, components inside the directory are , offering optimal performance and allowing developers to easily adopt them. app Server Components Here's an example structure: my-real-time-app/ │ ├── app/ # Main directory for App Router components │ ├── _error.js # Custom error page │ ├── _layout.js # Shared layout for the app │ │ │ ├── dashboard/ # Nested route example │ │ ├── index.js # Dashboard main view │ │ └── settings.js # Dashboard settings view │ │ │ ├── index.js # Landing/Home page │ ├── profile.js # User profile page │ ├── login.js # Login page │ └── register.js # Registration page │ ├── public/ # Static assets go here (images, fonts, etc.) │ ├── images/ │ └── favicon.ico │ ├── styles/ # Global styles or variables │ └── global.css │ ├── package.json # Dependencies and scripts ├── next.config.js # Next.js configuration └── README.md # Project documentation Server Components vs. Client Components Thinking about how components render is crucial. In traditional SPAs (Single Page Applications), React renders the entire application on the client side. With Server Components, much of the application renders on the server, leading to performance benefits. Here's a guideline: : Ideal for non-interactive parts of your application. These components are rendered on the server and sent to the client as HTML. The advantage here is improved performance, reduced client-side JavaScript, and the ability to fetch data or access backend resources directly. Server Components : Used for interactive UI elements. They're pre-rendered on the server and then "hydrated" on the client to add interactivity. Client Components To differentiate between these components, Next.js introduced the directive. This directive indicates that a component should be treated as a Client Component. It should be placed at the top of a component file, before any imports. "use client" For example, if you have an interactive counter, as in the provided code, you'll use the directive to indicate that it's a client-side component. "use client" Recommendations As you structure your application, here are some guidelines: Use by default (as they are in the directory). Server Components app Only opt for when you have specific use cases like adding interactivity, utilizing browser-only APIs, or leveraging React hooks that depend on state or browser functionalities. Client Components Following this structure and setup, you'll be well on your way to building a performant real-time application with Next.js 13.4's Server Actions. Notes: 5. Building the Backend: Leveraging Server Actions The power of Next.js 13.4 shines when integrating real-time backend functionalities into our project. Let's walk through the steps with relevant code examples for our . my-real-time-app Introduction to how server actions will be employed in this project For our , server actions act as our primary bridge between the and , allowing for efficient data transactions without the need for separate APIs. my-real-time-app frontend backend // my-real-time-app/app/actions/index.js

export * from './auth-action'; export * from './chat-action'; Setting up server actions for handling user authentication In , we leverage server actions to streamline the authentication process. my-real-time-app // my-real-time-app/app/actions/auth-action.js

export const login = async (credentials) => { // Logic for authenticating user with credentials // Return user details or error message };

export const logout = async (userId) => { // Logic for logging out the user // Return success or error message };

export const register = async (userInfo) => { // Logic for registering a new user // Store user in database and return success or error message }; Creating server actions for sending and receiving real-time messages For the chat functionality: // my-real-time-app/app/actions/chat-action.js

export const sendMessage = async (messageDetails) => { // Logic to send a new message // Store message in database and inform other users via WebSocket or similar };

export const receiveMessage = async () => { // Logic to receive a message in real-time // Return the message details };

export const getRecentMessages = async (userId) => { // Logic to fetch recent messages for the user // Retrieve messages from the database }; Integrating a database (e.g., MongoDB) for message persistence Using MongoDB as our primary data store: // Initialize MongoDB connection const { MongoClient } = require('mongodb'); const client = new MongoClient(process.env.MONGODB_URI); await client.connect();

// Now, use this connection in server actions to interact with the database. In our chat actions: // my-real-time-app/app/actions/chat-action.js

export const sendMessage = async (messageDetails) => { const messagesCollection = client.db('chatDB').collection('messages'); await messagesCollection.insertOne(messageDetails); // Inform other users via WebSocket or similar }; Ensuring secure and fast communication through server actions For security: // Middleware for validating request data const validateRequest = (req) => { // Validation logic here return isValid; };

export const sendMessage = async (messageDetails) => { if (!validateRequest(messageDetails)) { throw new Error("Invalid request data"); } // Remaining logic... }; 6. Designing the Frontend: A Seamless User Experience In this section, we'll construct an intuitive and responsive chat interface for . The integration of Next.js 13.4's server components will enable real-time updates for a smooth user experience. my-real-time-app Architecting the main chat interface Firstly, let's create the main chat interface: // my-real-time-app/app/chat-interface.js

import { useEffect, useState } from 'react'; import { getRecentMessages } from './actions/chat-action';

export default function ChatInterface() { const [messages, setMessages] = useState([]);

useEffect(() => { async function loadMessages() { const recentMessages = await getRecentMessages(); setMessages(recentMessages); }

loadMessages(); }, []);

return ( {messages.map(msg => ( {msg.content}

))} ); } This component fetches recent messages on load and renders them in a chatbox. Connecting the frontend to server actions for real-time updates Now, we'll set up real-time updates using a basic example of WebSockets: // my-real-time-app/app/chat-interface.js

const [socket, setSocket] = useState(null);

useEffect(() => { const ws = new WebSocket("ws://your-backend-url/ws");

ws.onmessage = (event) => { const newMessage = JSON.parse(event.data); setMessages(prevMessages => [...prevMessages, newMessage]); };

setSocket(ws); return () => { ws.close(); }; }, []); This hook establishes a WebSocket connection and updates the message list when a new message is received. Implementing notifications for new messages For a better UX, let's notify users of new messages: // my-real-time-app/app/chat-interface.js

useEffect(() => { if (messages.length && "Notification" in window && Notification.permission === "granted") { const lastMessage = messages[messages.length - 1]; new Notification(`New message from ${lastMessage.sender}: ${lastMessage.content}`); } }, [messages]); This effect sends a browser notification every time the messages list is updated with a new message. Techniques for ensuring smooth and lag-free user interactions To ensure a fluid experience: Lazy-load heavy components: const HeavyComponent = React.lazy(() => import('./HeavyComponent'));

function Chat() { return ( Loading... }> ); } Use Next.js's to split logic: React Server Components Remember from the earlier documentation, Server Components can be used for non-interactive parts, while Client Components can handle the interactive parts, reducing the amount of JavaScript sent to the client. For instance, in our chat, the message history can be a Server Component, while the input field and send button, which require client-side interactivity, can be Client Components. 7. Testing the Real-time Capabilities With the core components of our real-time application in place, it's essential to ensure that they function as expected, and are performant, scalable, and robust. This section sheds light on various testing approaches tailored for real-time systems like our . my-real-time-app Tools and strategies for testing real-time functionalities End-to-End Testing with Cypress For real-time applications, end-to-end tests are crucial. Let's set up an example with Cypress: // cypress/integration/chat.spec.js

describe('Chat functionality', () => { it('should send and receive messages in real-time', () => { cy.visit('/chat'); cy.get('[data-cy=messageInput]').type('Hello, World!'); cy.get('[data-cy=sendButton]').click(); cy.contains('Hello, World!').should('exist'); }); }); Load Testing with Artillery This will help in understanding how the system behaves under significant numbers of users or messages: # artillery-config.yml

config: target: 'http://my-real-time-app.com' phases: - duration: 300 arrivalRate: 20 scenarios: - flow: - emit: channel: 'chat' payload: message: 'Hello, World!' $ artillery run artillery-config.yml Addressing potential bottlenecks and performance issues Profiling Server Performance Node.js provides in-built tools for profiling, and the flag can be used with the Next.js development server to enable the Node.js inspector. By using Chrome's DevTools, one can get insights into performance bottlenecks. --inspect Client-side Performance Analysis For the client-side, tools like the tab in Chrome DevTools can help identify rendering bottlenecks. Especially with real-time updates, ensure that unnecessary renders aren't happening. Performance Ensuring scalability and robustness of the real-time application State Management with SWR or React Query Real-time applications often involve keeping the client's state in sync with the server. Libraries like SWR or React Query help in making this easier by offering features like automatic re-fetching, caching, and real-time synchronization. Example with SWR: // my-real-time-app/app/chat-interface.js

import useSWR from 'swr';

function ChatInterface() { const { data: messages } = useSWR('/api/messages', fetcher);

// ... rest of the component } Horizontal Scaling For backend scalability, especially with WebSockets, consider using a solution like Redis to manage the state across multiple instances of your server. This way, if one server instance receives a message, it can broadcast it to clients connected to other server instances. Database Optimization Ensure that your database queries, especially those that run frequently in real-time applications, are optimized. Index essential columns, and consider using database caching solutions for frequently accessed data. Testing real-time applications requires a combination of standard software testing techniques and some tailored specifically for the challenges and characteristics of real-time systems. Ensuring a rigorous testing regime for , we can guarantee a smooth and responsive user experience, irrespective of the scale of user traffic or data flow. Notes: my-real-time-app 10. Enhancements and Optimizations With the foundational architecture of our real-time application firmly in place, our attention now turns to refining its features and performance. Here are some strategies to enhance the user experience and optimize our : my-real-time-app Tips for enhancing the user experience Implementing Read Receipts Provide visual feedback to users when their messages have been read by the recipient. This enhances the interactive nature of real-time chats. // my-real-time-app/app/components/Message.js

function Message({ content, status }) { return ( {content}

{status === 'read' && ✓ Read } ); } Displaying Online Status Show an indicator next to a user's name or avatar when they are online. // my-real-time-app/app/components/UserStatus.js