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Follow this quickstart tutorial to add authentication to your React application

Authgear helps you add user logins to your React apps. It provides a pre-built login page and user settings page that can accelerate your development process.

Follow this 🕐 15-minute tutorial to create a simple app using React with the Authgear SDK.

Check out and clone the Sample Project on GitHub.

Table of Content

Setup Application in Authgear

To use Authgear's features, you'll need an account and a Project. Sign up for a free account at https://portal.authgear.com/ and create a new Project to get started.

After that, we will need to create an Application in the Project Portal.

Create an application in the Portal

To create a client application, first, go to Applications on the left menu bar in Authgear Portal.

Next, click ⊕Add Application in the top toolbar.

Input the name of your application, e.g. "MyAwesomeApp", then select Single Page Application as the Application Type.

Click the Save button to create the application.

Configure Authorize Redirect URI

The Authorized Redirect URI is a URL in you application where the user will be redirected to after login with Authgear. In this path, make a finish authentication call to complete the login process.

For this tutorial, add http://localhost:4000/auth-redirect to Authorize Redirect URIs.

Configure Post Logout Redirect URI

The Post Logout Redirect URI is the URL users will be redirected after they have logged out. The URL must be whitelisted.

For this tutorial, add http://localhost:4000/ to Post Logout Redirect URIs.

Click Save to keep all client app configuration changes before proceeding to the next steps.

Add Authgear to React App

In this section, we'll create a simple React application and connect it to Authgear such that, users of the app will log in, view their user settings, and log out of their account.

Step 1: Create a simple React project

Here are some recommended steps to scaffold a React project. You can skip this part if you are adding Authgear to an existing project. See #install-authgear-sdk-to-the-project in the next section.

Install basic project dependencies

Create the project folder and install the dependencies. We will use parcel as the build tool and the react-router-dom, react , and react-dom packages. Also, we will use TypeScript in this tutorial. 

# Create a new folder for your project
mkdir my-app
# Move into the project directory
cd my-app
# Create source folder
mkdir src
# Create a brand new package.json file
npm init -y
# Install parcel
npm install --save-dev --save-exact parcel
# Install react, react-dom and react router
npm install --save-exact react react-dom react-router-dom
# Install TypeScript and related types
npm install --save-dev --save-exact typescript @types/react @types/react-dom @types/react-router-dom

Add script for launching the app

In the package.json file, add these two lines to the script section

"start": "parcel serve --port 4000 --no-cache ./src/index.html",
"build": "parcel build --no-cache ./src/index.html"

The start script runs the app in development mode on port 4000. The build script build the app for production to the dist/ folder.

Create the index.html file

In src/, create a new file called index.html for parcel to bundle the app:

src/index.html:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Authgear React Tutorial Demo App</title>
  </head>
  <body>
    <div id="react-app-root"></div>
    <script type="module" src="./index.tsx"></script>
  </body>
</html>

Create the App.tsx file

Create a new file called App.tsx with simply showing Hello World in the screen: 

// src/App.tsx
import React from "react";

const App: React.FC = () => {
  return <div>Hello World</div>;
};

export default App;

Create the index.tsx file

Create a new file called index.tsx as the entry point of the application.

// src/index.tsx
import React from "react";
import { createRoot } from "react-dom/client";
import App from "./App";

async function init() {
  try {
   // initialization code
  } finally {
    createRoot(document.getElementById("react-app-root")!).render(<App />);
  }
}

init().catch((e) => {
  // Error handling
  console.error(e)
});

The file structure in your project is now:

my-app
├── node_modules
│   └── (...)
├── package-lock.json
├── package.json
└── src
    ├── App.tsx
    ├── index.html
    └── index.tsx

Run npm start now to run the project and you will see "Hello World" when you open http://localhost:4000 on a web browser.

Step 2: Install Authgear SDK to the project

Run the following command within your React project directory to install the Authgear Web SDK

npm install --save --save-exact @authgear/web

In src/index.tsx , import authgear and call the configure function to initialize an Authgear instance on application loads.

// src/index.tsx
import React from "react";
import { createRoot } from "react-dom/client";
import App from "./App";
import authgear from "@authgear/web";

async function init() {
  try {
    // configure Authgear container instance
    await authgear.configure({
      endpoint: "<your_app_endpoint>",
      clientID: "<your_client_id>",
      sessionType: "refresh_token",
    });
  } finally {
    createRoot(document.getElementById("react-app-root")!).render(<App />);
  }
}

init().catch((e) => {
  // Error handling
  console.error(e)
});

The Authgear container instance takes endpoint and clientID as parameters. They can be obtained from the configuration page for the application created in Setup Application in Authgear.

It is recommended to render the app after configure() resolves. So by the time the app is rendered, Authgear is ready to use.

Run npm start now and you should see a page with "Hello World" and no error message in the console if Authgear SDK is configured successfully

Step 3: Implement the Context Provider

Since we want to reference the logged-in state everywhere in the app, let's put the state in a context provider with UserProvider.tsx in the /src/context folder.

In UserProvider.tsx, there will be a isLoggedIn boolean and a setIsLoggedIn function. The isLoggedIn boolean state can be auto-updated using the onSessionStateChange callback. This callback can be stored in delegate which is in the local SDK container. 

// src/context/UserProvider.tsx
import React, { createContext, useEffect, useState, useMemo } from "react";
import authgear from "@authgear/web";

interface UserContextValue {
  isLoggedIn: boolean;
}

export const UserContext = createContext<UserContextValue>({
  isLoggedIn: false,
});

interface UserContextProviderProps {
  children: React.ReactNode;
}

const UserContextProvider: React.FC<UserContextProviderProps> = ({
  children,
}) => {
  // By default the user is not logged in
  const [isLoggedIn, setIsLoggedIn] = useState<boolean>(false);

  useEffect(() => {
    // When the sessionState changed, logged in state will also be changed
    authgear.delegate = {
      onSessionStateChange: (container) => {
        // sessionState is now up to date
        // Value of sessionState can be "NO_SESSION" or "AUTHENTICATED"
        const sessionState = container.sessionState;
        if (sessionState === "AUTHENTICATED") {
          setIsLoggedIn(true);
        } else {
          setIsLoggedIn(false);
        }
      },
    };
  }, [setIsLoggedIn]);

  const contextValue = useMemo<UserContextValue>(() => {
    return {
      isLoggedIn,
    };
  }, [isLoggedIn]);

  return (
    <UserContext.Provider value={contextValue}>{children}</UserContext.Provider>
  );
};

export default UserContextProvider;

Step 4: Implement the Auth Redirect

Next, we will add an "AuthRedirect" page for handling the authentication result after the user has been authenticated by Authgear.

Create the AuthRedirect.tsx component file in the src/ folder.

Call the Authgear finishAuthentication() function in the Auth Redirect component to send a token back to Authgear server in exchange for an access token and a refresh token. Don't worry about the technical jargons, finishAuthentication() will do all the hard work for you and and save the authentication data.

When the authentication is finished, the isLoggedIn state from the UserContextProvider will be automatically set to true. Finally, navigate back to root (/) which is our Home page.

The final AuthRedirect.tsx will look like this

// src/AuthRedirect.tsx
import React, { useEffect, useRef } from "react";
import { useNavigate } from "react-router-dom";
import authgear from "@authgear/web";

const AuthRedirect: React.FC = () => {
  const usedToken = useRef(false);

  const navigate = useNavigate();

  useEffect(() => {
    async function updateToken() {
      try {
        await authgear.finishAuthentication();
      } finally {
        navigate("/");
        usedToken.current = true;
      }
    }

    if (!usedToken.current) {
      updateToken().catch((e) => console.error(e));
    }
  }, [navigate]);

  return <></>;
};

export default AuthRedirect;

Since in React 18, useEffect will be fired twice in development mode, we need to implement a cleanup function to stop it from firing twice. We will use an useRef Hook to stop the user token from being sent twice to the Authgear Endpoint.

Without a cleanup function, anuseEffectHook will be fired twice and hence finishAuthentication() will send the token back to Authgear Endpoint for two times, which the second one will result in "Invalid Token" error since the token can only be used once.

Step 5: Add Routes and Context Provider to the App

Next, we will add a "Home" page. Create a Home.tsx component file the src/ folder.

Then import Home and AuthRedirect as routes. And Import UserContextProvider and wrap the routes with it.

Your final App.tsx should look like this:

// src/App.tsx
import React from "react";
import { BrowserRouter as Router, Routes, Route } from 'react-router-dom';
import Home from './Home';
import AuthRedirect from './AuthRedirect';
import UserContextProvider from './context/UserProvider';

const App: React.FC = () => {
  return (
    <UserContextProvider>
      <Router>
        <Routes>
          <Route path="/auth-redirect" element={<AuthRedirect />} />
          <Route path="/" element={<Home />} />
        </Routes>
      </Router>
    </UserContextProvider>
  );
}

export default App;

The file structure should now look like

src
├── App.tsx
├── AuthRedirect.tsx
├── Home.tsx
├── context
│   └── UserProvider.tsx
├── index.html
└── index.tsx

Step 6: Add a Login button

First, we will import the Authgear dependency and the React Hook that we will use to Home.tsx. Then add the login button which will call startAuthentication(ConfigureOptions) through the startLogin callback on click. This will redirect the user to the login page.

// src/Home.tsx
import React, { useEffect, useState, useCallback, useContext } from 'react';
import authgear from '@authgear/web';

const Home: React.FC = () => {
  const startLogin = useCallback(() => {
    authgear
      .startAuthentication({
        redirectURI: 'http://localhost:4000/auth-redirect',
        prompt: 'login'
      })
      .then(
        () => {
          // started authentication, user should be redirected to Authgear
        },
        err => {
          // failed to start authentication
        }
      );
  }, []);
  return (
    <div>
      <h1>Home Page</h1>
      <div>
        <button onClick={startLogin}>Login</button>
      </div>
    </div>
  );
}

export default Home;

You can now run npm start and you will be redirected to the Authgear Login page when you click the Login button.

Step 7: Show the user information

The Authgear SDK helps you get the information of the logged-in users easily.

In the last step, the user is successfully logged in, so let's try to print the user ID (sub) of the user on the Home page.

In Home.tsx, we will add a simple Loading splash and a greeting message printing the Sub ID. We will add two conditional elements such that they are only shown when user is logged in. We can also change the login button to show only if the user is not logged in.

Make use of isLoggedIn from the UserContext to control the components on the page. Fetch the user info by fetchInfo() and access its sub property.

// src/Home.tsx  
import React, { useEffect, useState, useCallback, useContext } from "react";
import authgear from "@authgear/web";
import { UserContext } from "./context/UserProvider";

const Home: React.FC = () => {
  const [greetingMessage, setGreetingMessage] = useState<string>("");
  const [isLoading, setIsLoading] = useState<boolean>(false);
  const { isLoggedIn } = useContext(UserContext);

  useEffect(() => {
    async function updateGreetingMessage() {
      setIsLoading(true);
      try {
        if (isLoggedIn) {
          const userInfo = await authgear.fetchUserInfo();
          setGreetingMessage("The current User sub: " + userInfo.sub);
        }
      } finally {
        setIsLoading(false);
      }
    }

    updateGreetingMessage().catch((e) => {
      console.error(e);
    });
  }, [isLoggedIn]);

  const startLogin = useCallback(() => {
    authgear
      .startAuthentication({
        redirectURI: "http://localhost:4000/auth-redirect",
        prompt: "login",
      })
      .then(
        () => {
          // started authentication, user should be redirected to Authgear
        },
        (err) => {
          // failed to start authentication
        }
      );
  }, []);

  return (
    <div>
      <h1>Home Page</h1>
      {isLoading && "Loading"}
      {greetingMessage ? <span>{greetingMessage}</span> : null}
      {!isLoggedIn && (
        <div>
          <button type="button" onClick={startLogin}>
            Login
          </button>
        </div>
      )}
    </div>
  );
};

export default Home;

Run the app again, the User ID (sub) of the user should be printed on the Home page.

Step 8: Add a Logout button

Now, let's add a Logout button that is displayed when the user is logged in.

In Home.tsx, we will add the following conditional elements below the conditional elements for the Login button :

{isLoggedIn && (
  <div>
    <button onClick={logout}>Logout</button>
  </div>
)}

And add the logout callback:

const logout = useCallback(() => {
  authgear
    .logout({
      redirectURI: "http://localhost:4000/",
    })
    .then(
      () => {
        setGreetingMessage('');
      },
      (err) => {
        console.error(err);
      }
  );
}, []);

Run the app again, we can now log out by clicking the Logout button.

Step 9: Open User Settings

Authgear provides a built-in UI for the users to set their attributes and change security settings.

Use the openURL function to open the settings page at <your_app_endpoint>/settings

In Home.tsx Add a conditional link to the existing elements.

{isLoggedIn && (
  <a target="_blank" rel="noreferrer" onClick={userSetting} href="#">
    User Setting
  </a>
)}

And add the userSetting callback:

import authgear, { Page } from "@authgear/web";
const userSetting = useCallback((e: React.MouseEvent<HTMLAnchorElement>) => {
    e.preventDefault();
    e.stopPropagation();
    authgear.open(Page.Settings);
}, []);

This is the resulting Home.tsx:

// src/Home.tsx
import React, { useEffect, useState, useCallback, useContext } from "react";
import { UserContext } from "./context/UserProvider";
import authgear, { Page } from "@authgear/web";

const Home: React.FC = () => {
  const [greetingMessage, setGreetingMessage] = useState<string>("");
  const [isLoading, setIsLoading] = useState<boolean>(false);
  const { isLoggedIn } = useContext(UserContext);

  useEffect(() => {
    async function updateGreetingMessage() {
      setIsLoading(true);
      try {
        if (isLoggedIn) {
          const userInfo = await authgear.fetchUserInfo();
          setGreetingMessage("The current User sub: " + userInfo.sub);
        }
      } finally {
        setIsLoading(false);
      }
    }

    updateGreetingMessage().catch((e) => {
      console.error(e);
    });
  }, [isLoggedIn]);

  const startLogin = useCallback(() => {
    authgear
      .startAuthentication({
        redirectURI: "http://localhost:4000/auth-redirect",
        prompt: "login",
      })
      .then(
        () => {
          // started authorization, user should be redirected to Authgear
        },
        (err) => {
          // failed to start authorization
          console.error(err);
        }
      );
  }, []);

  const logout = useCallback(() => {
    authgear
      .logout({
        redirectURI: "http://localhost:4000/",
      })
      .then(
        () => {
          setGreetingMessage("");
        },
        (err) => {
          console.error(err);
        }
      );
  }, []);

  const userSetting = useCallback((e: React.MouseEvent<HTMLAnchorElement>) => {
    e.preventDefault();
    e.stopPropagation();
    authgear.open(Page.Settings);
  }, []);

  return (
    <div>
      {/* eslint-disable-next-line react/forbid-elements */}
      <h1>Home Page</h1>
      {isLoading && "Loading"}
      {greetingMessage ? <span>{greetingMessage}</span> : null}
      {!isLoggedIn && (
        <div>
          <button type="button" onClick={startLogin}>
            Login
          </button>
        </div>
      )}
      {isLoggedIn && (
        <div>
          <button type="button" onClick={logout}>
            Logout
          </button>
          <br />
          <a target="_blank" rel="noreferrer" onClick={userSetting} href="#">
            User Setting
          </a>
        </div>
      )}
    </div>
  );
};

export default Home;

Next steps, Calling an API

To access restricted resources on your backend application server, the HTTP requests should include the access token in their Authorization headers. The Web SDK provides a fetch function which automatically handles this, or you can get the token with authgear.accessToken.

Option 1: Using fetch function provided by Authgear SDK

Authgear SDK provides the fetch function for you to call your application server. This fetch function will include the Authorization header in your application request, and handle the process of refreshing an access token automatically. The authgear.fetch implements fetch.

authgear
    .fetch("YOUR_SERVER_URL")
    .then(response => response.json())
    .then(data => console.log(data));

Option 2: Add the access token to the HTTP request header

You can get the access token through authgear.accessToken. Call refreshAccessTokenIfNeeded every time before using the access token, the function will check and make the network call to refresh the access token only if it is expired. Include the access token into the Authorization header of the application requests.

authgear
    .refreshAccessTokenIfNeeded()
    .then(() => {
        // access token is ready to use
        // accessToken can be string or undefined
        // it will be empty if user is not logged in or session is invalid
        const accessToken = authgear.accessToken;

        // include Authorization header in your application request
        const headers = {
            Authorization: `Bearer ${accessToken}`
        };
    });
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