The management of user access stands as a pivotal aspect of web application development. In this comprehensive guide, you will learn and understand the intricate workings of authorization and authentication in React.js. This article caters to readers possessing a fundamental understanding of React, providing them with invaluable insights. Moreover, seasoned front-end engineers will discover a detailed workflow for session management within the realm of this guide.
To get started, you will need to set up a React project by running the command
npx create-react-app your-project-name
Also, you can run
npm install react-router-dom
This will help you install React Router Dom for an efficient routing system.
Build Login Component
We'll start with a simple login component that accepts two inputs: an email field and a password field. When an onChange event occurs, these two input fields trigger the handleInput function. The name attribute on the input is also used by the function to set the input state. This is an effective method for managing input fields in ReactJS. If the button is pressed, the parent listens for an onSubmit event and invokes the handleSubmitEvent handler.
import { useState } from "react";
const Login = () => {
const [input, setInput] = useState({
username: "",
password: "",
});
const handleSubmitEvent = (e) => {
e.preventDefault();
if (input.username !== "" && input.password !== "") {
//dispatch action from hooks
}
alert("please provide a valid input");
};
const handleInput = (e) => {
const { name, value } = e.target;
setInput((prev) => ({
...prev,
[name]: value,
}));
};
return (
<form onSubmit={handleSubmitEvent}>
<div className="form_control">
<label htmlFor="user-email">Email:</label>
<input
type="email"
id="user-email"
name="email"
placeholder="example@yahoo.com"
aria-describedby="user-email"
aria-invalid="false"
onChange={handleInput}
/>
<div id="user-email" className="sr-only">
Please enter a valid username. It must contain at least 6 characters.
</div>
</div>
<div className="form_control">
<label htmlFor="password">Password:</label>
<input
type="password"
id="password"
name="password"
aria-describedby="user-password"
aria-invalid="false"
onChange={handleInput}
/>
<div id="user-password" className="sr-only">
your password should be more than 6 character
</div>
</div>
<button className="btn-submit">Submit</button>
</form>
);
};
export default Login;
This image shows the output of our login component, which contains two input fields and a button.
Create AuthContext and AuthProvider
The context API is generally used for managing states that will be needed across an application. For example, we need our user data or tokens that are returned as part of the login response in the dashboard components. Also, some parts of our application need user data as well, so making use of the context API is more than solving the problem for us.
Next, in an AuthProvider.js file, create an AuthContext for managing the user state and an AuthProvider for consuming the content of our context.
import { useContext, createContext } from "react";
const AuthContext = createContext();
const AuthProvider = ({ children }) => {
return <AuthContext.Provider>{children}</AuthContext.Provider>;
};
export default AuthProvider;
export const useAuth = () => {
return useContext(AuthContext);
};
The code set up above is used for creating the authentication context in React using the Context API. It creates an AuthContext using createContext() to manage the authentication state.
The AuthProvider component is designed to wrap the application and provide the authentication context to its child components using the AuthContext.Provider.
The useAuth custom hook utilizes useContext to access the authentication context from within components, allowing them to consume the authentication state and related functions stored in the context. As this article progresses, we will add the authentication logics that control the login and logout processes, passing them via the AuthContext.Provider. You will then have access to them and be able to use them when you call the useAuth function.
Next, import and wrap the AuthProvider around the app content in App.js.
import AuthProvider from "./hooks/AuthProvider";
function App() {
return (
<div className="App">
<AuthProvider>{/* App content */}</AuthProvider>
</div>
);
}
export default App;
Now that the AuthProvider has been wrapped around the App components, we can access all the context values in any of our pages or components within the application when we add all the routes needed to the App component.
Create Authentication Logic
Next, the AuthProvider component will be updated with login and logout functions. This function will be passed down through the AuthContext.Provider and it will be accessible globally.
import { useContext, createContext, useState } from "react";
import { useNavigate } from "react-router-dom";
const AuthContext = createContext();
const AuthProvider = ({ children }) => {
const [user, setUser] = useState(null);
const [token, setToken] = useState(localStorage.getItem("site") || "");
const navigate = useNavigate();
const loginAction = async (data) => {
try {
const response = await fetch("your-api-endpoint/auth/login", {
method: "POST",
headers: {
"Content-Type": "application/json",
},
body: JSON.stringify(data),
});
const res = await response.json();
if (res.data) {
setUser(res.data.user);
setToken(res.token);
localStorage.setItem("site", res.token);
navigate("/dashboard");
return;
}
throw new Error(res.message);
} catch (err) {
console.error(err);
}
};
const logOut = () => {
setUser(null);
setToken("");
localStorage.removeItem("site");
navigate("/login");
};
return (
<AuthContext.Provider value={{ token, user, loginAction, logOut }}>
{children}
</AuthContext.Provider>
);
};
export default AuthProvider;
export const useAuth = () => {
return useContext(AuthContext);
};
In this code, the AuthProvider component manages the user authentication state, providing functionalities like login, logout, and token storage using useState hooks.
The loginAction function handles user login by sending a POST request to an authentication endpoint, updating the user and token state upon a successful response, and storing the token in local storage.
The logOut function clears user and token data, removing the token from local storage. The AuthContext.Provider makes the authentication state and related functions available to its child components, accessible via the useAuth hook, enabling components to consume authentication data and actions within the application.
Protect Routes with Authorization
Next up, we will set up a route guard that protects any route that is private in the application. To achieve this, the useAuth hook for accessing our context data will be needed. Here is the code on how to work through it.
import React from "react";
import { Navigate, Outlet } from "react-router-dom";
import { useAuth } from "../hooks/AuthProvider";
const PrivateRoute = () => {
const user = useAuth();
if (!user.token) return <Navigate to="/login" />;
return <Outlet />;
};
export default PrivateRoute;
This code defines a PrivateRoute component for handling authentication. It utilizes the useAuth hook from the AuthProvider to access user authentication data. If the user does not possess a token, indicating they are not logged in, the code triggers a redirect to the /login route using the <Navigate> component. Otherwise, it renders the child components nested within the PrivateRoute component accessed via <Outlet />, allowing authenticated users to access the protected routes while redirecting unauthenticated users to the login page.
Add Routing
Next, we will update the App.js component by adding routing to it. It serves as the root component, enclosing the entire application. Within the App.js, it uses the Router component to set up the routing mechanism.
import { BrowserRouter as Router, Route, Routes } from "react-router-dom";
import Login from "./components/Login";
import Dashboard from "./components/Dashboard";
import AuthProvider from "./hooks/AuthProvider";
import PrivateRoute from "./router/route";
function App() {
return (
<div className="App">
<Router>
<AuthProvider>
<Routes>
<Route path="/login" element={<Login />} />
<Route element={<PrivateRoute />}>
<Route path="/dashboard" element={<Dashboard />} />
</Route>
{/* Other routes */}
</Routes>
</AuthProvider>
</Router>
</div>
);
}
export default App;
The Routes component establishes the route configuration: the '/login' path is mapped to the Login component, rendering it when the URL matches. The <PrivateRoute /> component serves as a guard for protecting the /dashboard route. When a user navigates to /dashboard, the PrivateRoute checks for authentication using the AuthProvider. If the user is authenticated (has a token), it renders the Dashboard component; otherwise, it redirects to the /login route, ensuring protected access to the dashboard.
API Integration
If you've reached this point, great job! We're nearing the end of this article. Yet there are a few more steps to cover. We've successfully created a login component, established an AuthContext to manage user sessions, and set up a route guard. Now, the next step is to trigger the login action by utilizing the useAuth hook to access the function. This approach enables the handleSubmitEvent function in the Login Component to trigger the API request. Upon a successful response, the tokens and user data will be saved and passed down through the AuthContext.
Here is the updated code for the login component.
import { useState } from "react";
import { useAuth } from "../hooks/AuthProvider";
const Login = () => {
const [input, setInput] = useState({
username: "",
password: "",
});
const auth = useAuth();
const handleSubmitEvent = (e) => {
e.preventDefault();
if (input.username !== "" && input.password !== "") {
auth.loginAction(input);
return;
}
alert("pleae provide a valid input");
};
return (
<form onSubmit={handleSubmitEvent}>
{/* Form inputs are provided in the above examples */}
</form>
);
};
export default Login;
The above example shows how to dispatch the loginAction using the useAuth hook.
Add Logout Button
Next, we need to add a button to dispatch the logOut action for ending the user session by clearing the user state in the context and also clarifying the token localStorage. Now create a dashboard component and add the code below.
import React, { useEffect } from "react";
import { useAuth } from "../hooks/AuthProvider";
const Dashboard = () => {
const auth = useAuth();
return (
<div className="container">
<div>
<h1>Welcome! {auth.user?.username}</h1>
<button onClick={() => auth.logOut()} className="btn-submit">
logout
</button>
</div>
</div>
);
};
export default Dashboard;
In the code above, the Dashboard component utilizes the useAuth hook from theAuthProvider to access authentication information. The component displays a welcome message with the username of the logged-in user and a logout button, which triggers the logOut function to log the user out.
The image above shows two input fields and a button. The user enters the email address and password.
This image illustrates the input data being passed as an object to the backend after a user enters their details.
This image depicts the backend API response data, which includes user data, user tasks, and a token for managing user sessions.
After logging in successfully, the user is redirected to the dashboard, where the username and logout buttons are displayed.
The images provided illustrate the login process from our implementation. When a user enters the correct information, it sends it to the server as a payload, and the server checks to see if the user exits. If they do, we receive a response with a user object containing all of the user's information, such as name and email address, and they are redirected to the dashboard page. In addition, we receive a token, which is saved to the browser's local storage. This allows us to manage user sessions more effectively. When the user clicks the log-out action, the last action occurs. It clears the user's local storage and redirects them to the login page.
Conclusion
Understanding how to use the Context API and React Router in authentication workflows is critical for managing user sessions in React applications. From creating authentication contexts to creating guarded routes and enabling user actions like login and logout, this comprehensive guide equips developers to handle user authentication seamlessly and securely within their React projects.
Top comments (29)
Building user authentication and authorization oneself, as part of the development of a project, is an option. And articles like this are a fantastic resource for showing you how; nice work @miracool 😎 However building user authentication and authorization when it's not ones core focus can lead to a whole lot of unnecessary work - that can also open an application to some unwanted and undesirable security implications. Check out my DEV post here to see how integrating with a SaaS platform - such as Auth0 - can be beneficial for a whole host of reasons 🤗
Hello Peter,
I have come to this post because I was looking for a solution for a react app, deployed with Netlify, that is easier than with Auth0. The test on localhost works fine. The application is a Single Page Application on Auth0. But now, when I want to use Autho0 for the web version, it becomes rather complicated. On Netlify, I read that I have to create a Machine to Machine application - and its getting complicated.
Therefore I am looking for a solution described here, relying on the power of React.
You write: "However building user authentication and authorization when it's not ones core focus can lead to a whole lot of unnecessary work". And exactly this is my impression with Auth0. I recommend, take the time and read documentation of Netlify & Auth0 with the eyes on someone with no core focus on that stuff.
Best,
Eckard
Hi Eckard,
Thanks for reaching out 😎
I'm glad to hear you've found integrating your React SPA with Auth0 works well - at least on
localhost- however, I am sorry to hear you're facing some challenges when using Netlify. I'm not an expert with Netlify per se, but I would recommend you check out our Netlify getting started guides on the Auth0 Developer Centre: developer.auth0.com/resources/get-.... In particular, the Build your Web Store with React, Auth0, Stripe and Netlify video (with Ben Dechrai, ex Auth0) does a great job of showing you how to integrate Auth0 as part of a React application deployed to Netlify.I'm also not sure which documentation you read concerning the creation of a Machine-to-Machine (M2M) application 🤔 But I'm guessing it might be the documentation on Netlify that's currently marked as "in beta"? I.e: docs.netlify.com/integrations/auth...? Correct? A Machine-to-Machine application is typically one where there is no user interaction; using the OAuth 2.0/OIDC Client Credentials grant, this is where an application would call an API - such as the Auth0 Management API - in what is a machine-level context.
If you do still find yourself struggling, please feel free to post over in our Community Forum (community.auth0.com/) and mention me in any question you post. Hopefully, we can get you up and running ASAP....and also share what we find with others who may be facing a similar challenge?!
All the best
Peter
the documentation on Netlify that's currently marked as "in beta"?
Yes. Thank you!
Finally, I managed to create a M2M application. But on Netlify it was not possible the configure it. The page URL looks like app.netlify.com/sites/xxxxx/integr...
Under this headline
Auth0 by Okta
Easily integrate your Auth0 tenants with Netlify.
Configuration
I did the prefix: REACT_APP_
I selected my tenant
But under
Configure Tenant - dev-t927qb8a
Manage Apps
It was not possible to select the respective app. The select menu did not show me this one. Seemlingly it only showed Single Page Apps but not M2M apps
The end of the story is: I cannot do this. Even if it had worked out now, I think, I cannot use it because I need a clear, reproducible path.
Thanks for the article, how would you handle a refresh endpoint call on app start
Hi Dusan, Thanks for the feedback! For this app, there's no support for a refresh token on the backend, but I did use a valid endpoint; I just changed it before publishing.
Okay, let's assume there's a refresh token. This is how I will handle it.
localStorage, we can check when an app starts to know if a token exists; iftrue, we can attempt to login the user by making a request to the refresh token; otherwise, redirect to the login page.Like for a refresh token?
I think he'll have to write a script to check with the backend if the access token sent is still valid.. if it's not the backend will check for the user with the expired acess token and if the user is found, the refresh route from the backend will be triggered... That's just my idea
my thoughts
Nice post. I am new to react js (actually focused on backend and react native). Your post has really helped me with this auth concept. Its pretty much simillar to what I do in react native. The effort you put in to explain every process to down to the smallest detail is commendable. Thanks again for this. My biggest issue which was using the context API with react routes has been visited here. Now I can rest easy on this.
Thanks for the kind words
Fantastic article. Was stuck with user context for one of my projects, but this article made me understand it better.
Bro oo, Nice article, I like the effort and detail you put into this, nicely done
I'm wondering how you got navigate("/dashboard"); in loginAction() to work? When I run the code, I get an error saying navigate() cannot be run outside of a Route context. I then tried to put navigate() inside a custom hook and call the hook from loginAction(). That didn't work either as a hook can only be called from a react component :(
Hi David, thanks for the feedback! From your error, it seems you have not set up your router. To use any react router method, you need to have your router set up properly first.
Hey thanks! I had my router setup but there was a small mistake in it. Your comment helped tremendously in finding my problem. I forgot to mention in my first post what a great writeup your article is. Thanks for posting it!
Glad it helped!
This is a nice article Makanju. I didn't really understand most of what you said here though 😂😂, because I haven't yet learnt about the Context API in React. But I have seen this will be very helpful for me going forward, and I have bookmarked it. Thank you!
Glad to have helped, cheers!
Awesome tutorial! Very well written.
Only one question- how would you use
localStoragemore? It's unclear if this is sufficient to store & retrieve the token, and it's definitely going to clear the user model between visits.It could more useful if you share server side code
Thanks for the feedback, i will share
@miracool please can you add the backend repo or the endpoint, for testing purposes? Thank you.
Aaah, great code along. I'm wondering what your server side code looks like ?
Hi Nicki, Thanks for the feedback, i will share.
do you know how to combine user auth with connect wallet function for web3?
Nah, why do you need that ?
Any thoughts about the security concerns about using localStorage for storing the token?
In case of a XSS the token can be fetched and sent to the hacker
Hi Mads, Making use of the refresh token would actually help in stopping or reducing any attack. because once a token has an expiration date, it won't later be useful for the hacker.
but I didn't implement a refresh token in this app.