SignIn with Google

9min
React Google Login
Introduction
In the last tutorial, you built a User login/logout feature to your App using the Parse.User class. Now you will learn how to use Google Sign-in to retrieve user data from Google and log in, sign up or link existent users with it. You will also install and configure react-google-login lib to achieve that.
The Parse.User.linkWith method is responsible for signing up and logging in users using any third-party authentication method, as long as you pass the right parameters requested by each different provider. After linking the user data to a new or existent Parse.User, Parse will store a valid user session on your device. Future calls to methods like current will successfully retrieve your User data, just like with regular logins.
Prerequisites
To complete this tutorial, you will need:

A React App created and connected to Back4App.
Complete the previous guide so you can have a better understanding of the Parse.User class and the Parse.User.logIn method﻿
If you want to test/use the screen layout provided by this guide, you should set up the ﻿Ant Design library.﻿
Goal
To build a User LogIn feature using Google Sign-in on Parse for a React App.
- Installing dependencies
The most popular way to enable Google Sign-in on React is using react-google-login to handle it. Set it up following the official docs.
Make sure to create an OAuth clientId in your Google Credentials page, adding your local development address to the authorized URLs, which generally is http://localhost:3000.
- Usign Google Sign-in with Parse
Let’s now create a new method inside the UserLogIn component that will handle the response when calling a Google Sign-in authentication modal. If the user signs in with Google, this call will retrieve the user data from Google and you need to store the id, idToken, and Google email. Then, the function will try to log in on Parse using the Parse.User.linkWith method and these credentials. Note that if your user had already signed up using this Google authentication, linkWith will log him in using the existent account.
JavaScript
TypeScript
const handleGoogleLoginLoginResponse = async function(response: any): Promise<boolean> {
 // Check if response has an error
 if (response.error !== undefined) {
   console.log(`Error: ${response.error}`);
   return false;
 } else {
   try {
     // Gather Google user info
     const userGoogleId: string = response.googleId;
     const userTokenId: string = response.tokenId;
     const userEmail: string = response.profileObj.email;
     // Try to login on Parse using linkWith and these credentials
     // Create a new Parse.User object
     const userToLogin: Parse.User = new Parse.User();
     // Set username and email to match google email
     userToLogin.set('username', userEmail);
     userToLogin.set('email', userEmail);
     try {
       let loggedInUser: Parse.User = await userToLogin
       .linkWith('google', {
         authData: {id: userGoogleId, id_token: userTokenId},
       });
       // logIn returns the corresponding ParseUser object
       alert(
         `Success! User ${loggedInUser.get('username')} has successfully signed in!`,
       );
       // Update state variable holding current user
       getCurrentUser();
       return true;
     } catch (error: any) {
       // Error can be caused by wrong parameters or lack of Internet connection
       alert(`Error! ${error.message}`);
       return false;
     }
   } catch (error: any) {
     console.log("Error gathering Google user info, please try again!")
     return false;
   }
 }
}
const handleGoogleLoginLoginResponse = async function(response: any): Promise<boolean> {
 // Check if response has an error
 if (response.error !== undefined) {
   console.log(`Error: ${response.error}`);
   return false;
 } else {
   try {
     // Gather Google user info
     const userGoogleId: string = response.googleId;
     const userTokenId: string = response.tokenId;
     const userEmail: string = response.profileObj.email;
     // Try to login on Parse using linkWith and these credentials
     // Create a new Parse.User object
     const userToLogin: Parse.User = new Parse.User();
     // Set username and email to match google email
     userToLogin.set('username', userEmail);
     userToLogin.set('email', userEmail);
     try {
       let loggedInUser: Parse.User = await userToLogin
       .linkWith('google', {
         authData: {id: userGoogleId, id_token: userTokenId},
       });
       // logIn returns the corresponding ParseUser object
       alert(
         `Success! User ${loggedInUser.get('username')} has successfully signed in!`,
       );
       // Update state variable holding current user
       getCurrentUser();
       return true;
     } catch (error: any) {
       // Error can be caused by wrong parameters or lack of Internet connection
       alert(`Error! ${error.message}`);
       return false;
     }
   } catch (error: any) {
     console.log("Error gathering Google user info, please try again!")
     return false;
   }
 }
}
﻿
After that, you need to use the react-google-login GoogleLogin component to call the Google SignIn modal, adding it to your JSX code. You can use Google’s default styling or create a custom one, which is the way followed by this guide. Here is the full UserLogin component code, note the react-google-login button and how it is tied to the modal response method created before.
JavaScript
TypeScript
import React, { useState, FC, ReactElement } from 'react';
import './App.css';
import { Button, Divider, Input } from 'antd';
import GoogleLogin from 'react-google-login';
const Parse = require('parse/dist/parse.min.js');

export const UserLogin: FC<{}> = (): ReactElement => {
 // State variables
 const [username, setUsername] = useState('');
 const [password, setPassword] = useState('');
 const [currentUser, setCurrentUser] = useState<Parse.Object | null>(null);

 const doUserLogIn = async function (): Promise<boolean> {
   // Note that these values come from state variables that we've declared before
   const usernameValue: string = username;
   const passwordValue: string = password;
   try {
     const loggedInUser: Parse.User = await Parse.User.logIn(usernameValue, passwordValue);
     // logIn returns the corresponding ParseUser object
     alert(
       `Success! User ${loggedInUser.get('username')} has successfully signed in!`,
     );
     // To verify that this is in fact the current user, `current` can be used
     const currentUser: Parse.User = await Parse.User.current();
     console.log(loggedInUser === currentUser);
     // Clear input fields
     setUsername('');
     setPassword('');
     // Update state variable holding current user
     getCurrentUser();
     return true;
   } catch (error: any) {
     // Error can be caused by wrong parameters or lack of Internet connection
     alert(`Error! ${error.message}`);
     return false;
   }
 };

 const doUserLogOut = async function (): Promise<boolean> {
   try {
     await Parse.User.logOut();
     // To verify that current user is now empty, currentAsync can be used
     const currentUser: Parse.User = await Parse.User.current();
     if (currentUser === null) {
       alert('Success! No user is logged in anymore!');
     }
     // Update state variable holding current user
     getCurrentUser();
     return true;
   } catch (error: any) {
     alert(`Error! ${error.message}`);
     return false;
   }
 };

 // Function that will return current user and also update current username
 const getCurrentUser = async function (): Promise<Parse.User | null> {
   const currentUser: (Parse.User | null) = await Parse.User.current();
   // Update state variable holding current user
   setCurrentUser(currentUser);
   return currentUser;
 }

 const handleGoogleLoginLoginResponse = async function(response: any): Promise<boolean> {
   // Check if response has an error
   if (response.error !== undefined) {
     console.log(`Error: ${response.error}`);
     return false;
   } else {
     try {
       // Gather Google user info
       const userGoogleId: string = response.googleId;
       const userTokenId: string = response.tokenId;
       const userEmail: string = response.profileObj.email;
       // Try to login on Parse using linkWith and these credentials
       // Create a new Parse.User object
       const userToLogin: Parse.User = new Parse.User();
       // Set username and email to match google email
       userToLogin.set('username', userEmail);
       userToLogin.set('email', userEmail);
       try {
         let loggedInUser: Parse.User = await userToLogin
         .linkWith('google', {
           authData: {id: userGoogleId, id_token: userTokenId},
         });
         // logIn returns the corresponding ParseUser object
         alert(
           `Success! User ${loggedInUser.get('username')} has successfully signed in!`,
         );
         // Update state variable holding current user
         getCurrentUser();
         return true;
       } catch (error: any) {
         // Error can be caused by wrong parameters or lack of Internet connection
         alert(`Error! ${error.message}`);
         return false;
       }
     } catch (error: any) {
       console.log("Error gathering Google user info, please try again!")
       return false;
     }
   }
 }

 return (
   <div>
     <div className="header">
       <img
         className="header_logo"
         alt="Back4App Logo"
         src={
           'https://blog.back4app.com/wp-content/uploads/2019/05/back4app-white-logo-500px.png'
         }
       />
       <p className="header_text_bold">{'React on Back4App'}</p>
       <p className="header_text">{'User Login'}</p>
     </div>
     {currentUser === null && (
       <div className="container">
         <h2 className="heading">{'User Login'}</h2>
         <Divider />
         <div className="form_wrapper">
           <Input
             value={username}
             onChange={(event) => setUsername(event.target.value)}
             placeholder="Username"
             size="large"
             className="form_input"
           />
           <Input
             value={password}
             onChange={(event) => setPassword(event.target.value)}
             placeholder="Password"
             size="large"
             type="password"
             className="form_input"
           />
         </div>
         <div className="form_buttons">
           <Button
             onClick={() => doUserLogIn()}
             type="primary"
             className="form_button"
             color={'#208AEC'}
             size="large"
             block
           >
             Log In
           </Button>
         </div>
         <Divider />
         <div className="login-social">
           <div className="login-social-item login-social-item--facebook">
             <img className="login-social-item__image" src={'https://findicons.com/files/icons/2830/clean_social_icons/250/facebook.png'} alt=""/>
           </div>
           <GoogleLogin
             clientId="108490793456-0flm4qh8ek4cb4krt7e06980o4sjvado.apps.googleusercontent.com"
             render={renderProps => (
                 <div className="login-social-item">
                   <img onClick={renderProps.onClick} className="login-social-item__image" src={'data:image/png;base64,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'} alt=""/>
                 </div>
             )}
             buttonText="Login"
             onSuccess={handleGoogleLoginLoginResponse}
             onFailure={handleGoogleLoginLoginResponse}
             cookiePolicy={'single_host_origin'}
           />
           <div className="login-social-item">
             <img className="login-social-item__image" src={'data:image/png;base64,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'} alt=""/>
           </div>
         </div>
         <p className="form__hint">Don't have an account? <a className="form__link" href="#">Sign up</a></p>
       </div>
     )}
     {currentUser !== null && (
       <div className="container">
         <h2 className="heading">{'User Screen'}</h2>
         <Divider />
         <h2 className="heading">{`Hello ${currentUser.get('username')}!`}</h2>
         <div className="form_buttons">
           <Button
             onClick={() => doUserLogOut()}
             type="primary"
             className="form_button"
             color={'#208AEC'}
             size="large"
             block
           >
             Log Out
           </Button>
         </div>
       </div>
     )}
   </div>
 );
};
import React, { useState, FC, ReactElement } from 'react';
import './App.css';
import { Button, Divider, Input } from 'antd';
import GoogleLogin from 'react-google-login';
const Parse = require('parse/dist/parse.min.js');

export const UserLogin: FC<{}> = (): ReactElement => {
 // State variables
 const [username, setUsername] = useState('');
 const [password, setPassword] = useState('');
 const [currentUser, setCurrentUser] = useState<Parse.Object | null>(null);

 const doUserLogIn = async function (): Promise<boolean> {
   // Note that these values come from state variables that we've declared before
   const usernameValue: string = username;
   const passwordValue: string = password;
   try {
     const loggedInUser: Parse.User = await Parse.User.logIn(usernameValue, passwordValue);
     // logIn returns the corresponding ParseUser object
     alert(
       `Success! User ${loggedInUser.get('username')} has successfully signed in!`,
     );
     // To verify that this is in fact the current user, `current` can be used
     const currentUser: Parse.User = await Parse.User.current();
     console.log(loggedInUser === currentUser);
     // Clear input fields
     setUsername('');
     setPassword('');
     // Update state variable holding current user
     getCurrentUser();
     return true;
   } catch (error: any) {
     // Error can be caused by wrong parameters or lack of Internet connection
     alert(`Error! ${error.message}`);
     return false;
   }
 };

 const doUserLogOut = async function (): Promise<boolean> {
   try {
     await Parse.User.logOut();
     // To verify that current user is now empty, currentAsync can be used
     const currentUser: Parse.User = await Parse.User.current();
     if (currentUser === null) {
       alert('Success! No user is logged in anymore!');
     }
     // Update state variable holding current user
     getCurrentUser();
     return true;
   } catch (error: any) {
     alert(`Error! ${error.message}`);
     return false;
   }
 };

 // Function that will return current user and also update current username
 const getCurrentUser = async function (): Promise<Parse.User | null> {
   const currentUser: (Parse.User | null) = await Parse.User.current();
   // Update state variable holding current user
   setCurrentUser(currentUser);
   return currentUser;
 }

 const handleGoogleLoginLoginResponse = async function(response: any): Promise<boolean> {
   // Check if response has an error
   if (response.error !== undefined) {
     console.log(`Error: ${response.error}`);
     return false;
   } else {
     try {
       // Gather Google user info
       const userGoogleId: string = response.googleId;
       const userTokenId: string = response.tokenId;
       const userEmail: string = response.profileObj.email;
       // Try to login on Parse using linkWith and these credentials
       // Create a new Parse.User object
       const userToLogin: Parse.User = new Parse.User();
       // Set username and email to match google email
       userToLogin.set('username', userEmail);
       userToLogin.set('email', userEmail);
       try {
         let loggedInUser: Parse.User = await userToLogin
         .linkWith('google', {
           authData: {id: userGoogleId, id_token: userTokenId},
         });
         // logIn returns the corresponding ParseUser object
         alert(
           `Success! User ${loggedInUser.get('username')} has successfully signed in!`,
         );
         // Update state variable holding current user
         getCurrentUser();
         return true;
       } catch (error: any) {
         // Error can be caused by wrong parameters or lack of Internet connection
         alert(`Error! ${error.message}`);
         return false;
       }
     } catch (error: any) {
       console.log("Error gathering Google user info, please try again!")
       return false;
     }
   }
 }

 return (
   <div>
     <div className="header">
       <img
         className="header_logo"
         alt="Back4App Logo"
         src={
           'https://blog.back4app.com/wp-content/uploads/2019/05/back4app-white-logo-500px.png'
         }
       />
       <p className="header_text_bold">{'React on Back4App'}</p>
       <p className="header_text">{'User Login'}</p>
     </div>
     {currentUser === null && (
       <div className="container">
         <h2 className="heading">{'User Login'}</h2>
         <Divider />
         <div className="form_wrapper">
           <Input
             value={username}
             onChange={(event) => setUsername(event.target.value)}
             placeholder="Username"
             size="large"
             className="form_input"
           />
           <Input
             value={password}
             onChange={(event) => setPassword(event.target.value)}
             placeholder="Password"
             size="large"
             type="password"
             className="form_input"
           />
         </div>
         <div className="form_buttons">
           <Button
             onClick={() => doUserLogIn()}
             type="primary"
             className="form_button"
             color={'#208AEC'}
             size="large"
             block
           >
             Log In
           </Button>
         </div>
         <Divider />
         <div className="login-social">
           <div className="login-social-item login-social-item--facebook">
             <img className="login-social-item__image" src={'https://findicons.com/files/icons/2830/clean_social_icons/250/facebook.png'} alt=""/>
           </div>
           <GoogleLogin
             clientId="108490793456-0flm4qh8ek4cb4krt7e06980o4sjvado.apps.googleusercontent.com"
             render={renderProps => (
                 <div className="login-social-item">
                   <img onClick={renderProps.onClick} className="login-social-item__image" src={'data:image/png;base64,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'} alt=""/>
                 </div>
             )}
             buttonText="Login"
             onSuccess={handleGoogleLoginLoginResponse}
             onFailure={handleGoogleLoginLoginResponse}
             cookiePolicy={'single_host_origin'}
           />
           <div className="login-social-item">
             <img className="login-social-item__image" src={'data:image/png;base64,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'} alt=""/>
           </div>
         </div>
         <p className="form__hint">Don't have an account? <a className="form__link" href="#">Sign up</a></p>
       </div>
     )}
     {currentUser !== null && (
       <div className="container">
         <h2 className="heading">{'User Screen'}</h2>
         <Divider />
         <h2 className="heading">{`Hello ${currentUser.get('username')}!`}</h2>
         <div className="form_buttons">
           <Button
             onClick={() => doUserLogOut()}
             type="primary"
             className="form_button"
             color={'#208AEC'}
             size="large"
             block
           >
             Log Out
           </Button>
         </div>
       </div>
     )}
   </div>
 );
};
﻿
Add these classes to your App.css file if you want to fully render this component’s layout.
App.css
@import '~antd/dist/antd.css';

.App {
 text-align: center;
}

html {
 box-sizing: border-box;
 outline: none;
 overflow: auto;
}

*,
*:before,
*:after {
 margin: 0;
 padding: 0;
 box-sizing: inherit;
}

h1,
h2,
h3,
h4,
h5,
h6 {
 margin: 0;
 font-weight: bold;
}

p {
 margin: 0;
}

body {
 margin: 0;
 background-color: #fff;
}

.container {
 width: 100%;
 max-width: 900px;
 margin: auto;
 padding: 20px 0;
 text-align: left;
}

.header {
 align-items: center;
 padding: 25px 0;
 background-color: #208AEC;
}

.header_logo {
 height: 55px;
 margin-bottom: 20px;
 object-fit: contain;
}

.header_text_bold {
 margin-bottom: 3px;
 color: rgba(255, 255, 255, 0.9);
 font-size: 16px;
 font-weight: bold;
}

.header_text {
 color: rgba(255, 255, 255, 0.9);
 font-size: 15px;
}

.heading {
 font-size: 22px;
}

.flex {
 display: flex;
}

.flex_between {
 display: flex;
 justify-content: space-between;
}

.flex_child {
 flex: 0 0 45%;
}

.heading_button {
 margin-left: 12px;
}

.list_item {
 padding-bottom: 15px;
 margin-bottom: 15px;
 border-bottom: 1px solid rgba(0, 0, 0, 0.06);
 text-align: left;
}

.list_item_title {
 color: rgba(0, 0, 0, 0.87);
 font-size: 17px;
}

.list_item_description {
 color: rgba(0, 0, 0, 0.5);
 font-size: 15px;
}

.form_input {
 margin-bottom: 20px;
}

.login-social {
 display: flex;
 justify-content: center;
 margin-bottom: 30px;
}

.login-social-item {
 width: 54px;
 height: 54px;
 border-radius: 54px;
 padding: 12px;
 margin: 0 12px;
 border: 1px solid #e6e6e6;
 box-shadow: 0 2px 4px #d6d6d6;
}

.login-social-item--facebook {
 padding: 4px;
 background-color: #3C5B9B;
}

.login-social-item__image {
 width: 100%;
}

.form__hint {
 color: rgba(0, 0, 0, 0.5);
 font-size: 16px;
 text-align: center;
}
@import '~antd/dist/antd.css';

.App {
 text-align: center;
}

html {
 box-sizing: border-box;
 outline: none;
 overflow: auto;
}

*,
*:before,
*:after {
 margin: 0;
 padding: 0;
 box-sizing: inherit;
}

h1,
h2,
h3,
h4,
h5,
h6 {
 margin: 0;
 font-weight: bold;
}

p {
 margin: 0;
}

body {
 margin: 0;
 background-color: #fff;
}

.container {
 width: 100%;
 max-width: 900px;
 margin: auto;
 padding: 20px 0;
 text-align: left;
}

.header {
 align-items: center;
 padding: 25px 0;
 background-color: #208AEC;
}

.header_logo {
 height: 55px;
 margin-bottom: 20px;
 object-fit: contain;
}

.header_text_bold {
 margin-bottom: 3px;
 color: rgba(255, 255, 255, 0.9);
 font-size: 16px;
 font-weight: bold;
}

.header_text {
 color: rgba(255, 255, 255, 0.9);
 font-size: 15px;
}

.heading {
 font-size: 22px;
}

.flex {
 display: flex;
}

.flex_between {
 display: flex;
 justify-content: space-between;
}

.flex_child {
 flex: 0 0 45%;
}

.heading_button {
 margin-left: 12px;
}

.list_item {
 padding-bottom: 15px;
 margin-bottom: 15px;
 border-bottom: 1px solid rgba(0, 0, 0, 0.06);
 text-align: left;
}

.list_item_title {
 color: rgba(0, 0, 0, 0.87);
 font-size: 17px;
}

.list_item_description {
 color: rgba(0, 0, 0, 0.5);
 font-size: 15px;
}

.form_input {
 margin-bottom: 20px;
}

.login-social {
 display: flex;
 justify-content: center;
 margin-bottom: 30px;
}

.login-social-item {
 width: 54px;
 height: 54px;
 border-radius: 54px;
 padding: 12px;
 margin: 0 12px;
 border: 1px solid #e6e6e6;
 box-shadow: 0 2px 4px #d6d6d6;
}

.login-social-item--facebook {
 padding: 4px;
 background-color: #3C5B9B;
}

.login-social-item__image {
 width: 100%;
}

.form__hint {
 color: rgba(0, 0, 0, 0.5);
 font-size: 16px;
 text-align: center;
}
﻿
Go ahead and test your new function. If you were able to sign in to Google and the Parse linkWith call was successful, you should see a success message like this.
﻿
- Verifying user sign in and session creation
To make sure that the Google sign-in worked, you can look at your Parse dashboard and see your new User (if your Google authentication data didn’t belong to another user), containing the Google authData parameters.
﻿
You can also verify that a valid session was created in the dashboard, containing a pointer to that User object.
﻿
- Linking an existing User to Google Sign-in
Another linkWith possible use is to link an existing user with another auth provider, in this case, Google. Add this function that calls linkWith the same way as logging in to your UserLogIn component. The only difference here is that instead of calling the method from an empty Parse.User, you will use it from the currently logged-in user object.
JavaScript
TypeScript
const handleGoogleLoginLinkResponse = async function(response) {
 // Check if response has an error
 if (response.error !== undefined) {
   console.log(`Error: ${response.error}`);
   return false;
 } else {
   try {
     // Gather Google user info
     const userGoogleId = response.googleId;
     const userTokenId = response.tokenId;
     // Try to link current Parse user using linkWith and these credentials
     // Get current user
     const userToLink = await Parse.User.current();
     try {
       let loggedInUser = await userToLink
       .linkWith('google', {
         authData: {id: userGoogleId, id_token: userTokenId},
       });
       // logIn returns the corresponding ParseUser object
       alert(
         `Success! User ${loggedInUser.get(
           'username',
         )} has successfully linked his Google account!`,
       );
       // Update state variable holding current user
       getCurrentUser();
       return true;
     } catch (error) {
       // Error can be caused by wrong parameters or lack of Internet connection
       alert(`Error! ${error.message}`);
       return false;
     }
   } catch (error) {
     console.log("Error gathering Google user info, please try again!")
     return false;
   }
 }
}
const handleGoogleLoginLinkResponse = async function(response) {
 // Check if response has an error
 if (response.error !== undefined) {
   console.log(`Error: ${response.error}`);
   return false;
 } else {
   try {
     // Gather Google user info
     const userGoogleId = response.googleId;
     const userTokenId = response.tokenId;
     // Try to link current Parse user using linkWith and these credentials
     // Get current user
     const userToLink = await Parse.User.current();
     try {
       let loggedInUser = await userToLink
       .linkWith('google', {
         authData: {id: userGoogleId, id_token: userTokenId},
       });
       // logIn returns the corresponding ParseUser object
       alert(
         `Success! User ${loggedInUser.get(
           'username',
         )} has successfully linked his Google account!`,
       );
       // Update state variable holding current user
       getCurrentUser();
       return true;
     } catch (error) {
       // Error can be caused by wrong parameters or lack of Internet connection
       alert(`Error! ${error.message}`);
       return false;
     }
   } catch (error) {
     console.log("Error gathering Google user info, please try again!")
     return false;
   }
 }
}
﻿
Assign this function to another react-google-login component in your home screen, which is shown only when there is a current user logged in in your app. Test your new function, noting that the Parse.User object authData value will be updated with the new auth provider data. Verify if the user has indeed updated in your Parse server dashboard.
﻿
Conclusion
At the end of this guide, you learned how to log in, sign up or link existing Parse users on React using Google Sign-in with react-google-login. In the next guide, we will show you how to use Apple sign-in.