React Native Facebook login
Introduction
In the last tutorials, you built a User login/logout feature to your App using the Parse.User
class. Now you will learn how to use Facebook FBSDK Login to retrieve user data from Facebook and log in, sign up or link existent users with it. You will also install and configure the react-native-fbsdk
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 in your device. Future calls to methods like currentAsync
will successfully retrieve your User data, just like with regular logins.
At any time, you can access this project via our GitHub repositories to checkout the styles and complete code.
Prerequisites
To complete this tutorial, you will need:
- A React Native App created and connected to Back4App.
- Complete the previous guides so you can have a better understanding of the Parse.User class and the Parse.User.logIn method.
Goal
To build a User LogIn feature using Facebook FBSDK Login on Parse for a React Native App.
Step 1 - Installing dependencies
The most popular way to add Facebook login on React Native is using react-native-fbsdk
to handle it. Since this library configuration depends on your development environment, target platform, and preferences, set it up following the official docs.
Note: If you are developing for iOS, make sure that your project has support for Swift files, containing a Bridging Header. Also, pay close attention to where you add the Facebook App IDs inside your
info.plist
file and if your Pods files are correctly generated.
Step 2 - Using FBSDK Login with Parse
Let’s now create a new method inside the UserLogIn
component calling Facebook FBSDK authentication modal with LoginManager.logInWithPermissions
, requesting permission only to access the user email. If the user successfully signs in with Facebook, you can then call AccessToken.getCurrentAccessToken
to retrieve the user access token from Facebook. After that, you still need to get the user id
and email
using a GraphRequest
through FBSDK GraphRequestManager
.
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const doUserLogInFacebook = async function () {
try {
// Login using the Facebook login dialog asking form email permission
return await LoginManager.logInWithPermissions(['email']).then(
(loginResult) => {
if (loginResult.isCancelled) {
console.log('Login cancelled');
return false;
} else {
// Retrieve access token from FBSDK to be able to linkWith Parse
AccessToken.getCurrentAccessToken().then((data) => {
const facebookAccessToken = data.accessToken;
// Callback that will be called after FBSDK successfuly retrieves user email and id from FB
const responseEmailCallback = async (
error,
emailResult,
) => {
if (error) {
console.log('Error fetching data: ' + error.toString());
} else {
// Format authData to provide correctly for Facebook linkWith on Parse
const facebookId = emailResult.id;
const facebookEmail = emailResult.email;
const authData = {
id: facebookId,
access_token: facebookAccessToken,
};
// Log in or sign up on Parse using this Facebook credentials
let userToLogin = new Parse.User();
// Set username and email to match provider email
userToLogin.set('username', facebookEmail);
userToLogin.set('email', facebookEmail);
return await userToLogin
.linkWith('facebook', {
authData: authData,
})
.then(async (loggedInUser) => {
// logIn returns the corresponding ParseUser object
Alert.alert(
'Success!',
`User ${loggedInUser.get(
'username',
)} has successfully signed in!`,
);
// To verify that this is in fact the current user, currentAsync can be used
const currentUser = await Parse.User.currentAsync();
console.log(loggedInUser === currentUser);
// Navigation.navigate takes the user to the screen named after the one
// passed as parameter
navigation.navigate('Home');
return true;
})
.catch(async (error) => {
// Error can be caused by wrong parameters or lack of Internet connection
Alert.alert('Error!', error.message);
return false;
});
}
};
// Formats a FBSDK GraphRequest to retrieve user email and id
const emailRequest = new GraphRequest(
'/me',
{
accessToken: facebookAccessToken,
parameters: {
fields: {
string: 'email',
},
},
},
responseEmailCallback,
);
// Start the graph request, which will call the callback after finished
new GraphRequestManager().addRequest(emailRequest).start();
return true;
});
}
},
(error) => {
console.log('Login fail with error: ' + error);
return false;
},
);
} catch (error) {
Alert.alert('Error!', error.code);
return false;
}
};
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const doUserLogInFacebook = async function (): Promise<boolean> {
try {
// Login using the Facebook login dialog asking form email permission
return await LoginManager.logInWithPermissions(['email']).then(
(loginResult: object) => {
if (loginResult.isCancelled) {
console.log('Login cancelled');
return false;
} else {
// Retrieve access token from FBSDK to be able to linkWith Parse
AccessToken.getCurrentAccessToken().then((data: object) => {
const facebookAccessToken = data.accessToken;
// Callback that will be called after FBSDK successfuly retrieves user email and id from FB
const responseEmailCallback = async (
error: string,
emailResult: object,
) => {
if (error) {
console.log('Error fetching data: ' + error.toString());
} else {
// Format authData to provide correctly for Facebook linkWith on Parse
const facebookId: string = emailResult.id;
const facebookEmail: string = emailResult.email;
const authData: object = {
id: facebookId,
access_token: facebookAccessToken,
};
// Log in or sign up on Parse using this Facebook credentials
let userToLogin: Parse.User = new Parse.User();
// Set username and email to match provider email
userToLogin.set('username', facebookEmail);
userToLogin.set('email', facebookEmail);
return await userToLogin
.linkWith('facebook', {
authData: authData,
})
.then(async (loggedInUser: Parse.User) => {
// logIn returns the corresponding ParseUser object
Alert.alert(
'Success!',
`User ${loggedInUser.get(
'username',
)} has successfully signed in!`,
);
// To verify that this is in fact the current user, currentAsync can be used
const currentUser: Parse.User = await Parse.User.currentAsync();
console.log(loggedInUser === currentUser);
// Navigation.navigate takes the user to the screen named after the one
// passed as parameter
navigation.navigate('Home');
return true;
})
.catch(async (error: object) => {
// Error can be caused by wrong parameters or lack of Internet connection
Alert.alert('Error!', error.message);
return false;
});
}
};
// Formats a FBSDK GraphRequest to retrieve user email and id
const emailRequest = new GraphRequest(
'/me',
{
accessToken: facebookAccessToken,
parameters: {
fields: {
string: 'email',
},
},
},
responseEmailCallback,
);
// Start the graph request, which will call the callback after finished
new GraphRequestManager().addRequest(emailRequest).start();
return true;
});
}
},
(error: string) => {
console.log('Login fail with error: ' + error);
return false;
},
);
} catch (error: object) {
Alert.alert('Error!', error.code);
return false;
}
};
Note that after the GraphRequest
succeeds, this function uses Parse.User.linkWith
on a new Parse.User
object to register a new user or log in a previous one with these credentials, passing his Facebook authentication data accordingly.
Add this function to your UserSignIn
component and assign it to your Facebook button onPress
parameter. Go ahead and test your new function, you will see that the user will be redirected to your home screen after successfully signing in.
Step 3 - Verifying user sign in and session creation
To make sure that the Facebook sign-in worked, you can look at your Parse dashboard and see your new User
(if your Facebook authentication data didn’t belong to another user), containing the Facebook authData
parameters.
You can also verify that a valid session was created in the dashboard, containing a pointer to that User
object.
Step 4 - Linking an existing User to FBSDK Login
Another linkWith
possible use is to link an existing user with another auth provider, in this case, Facebook. Add this function that calls linkWith
the same way you did in UserLogIn
to your HelloUser
component or directly to your home screen. The only difference here is that instead of calling the method from an empty Parse.User
, you will use it from the logged-in user object.
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const doUserLinkFacebook = async function () {
try {
// Login using the Facebook login dialog asking form email permission
return await LoginManager.logInWithPermissions(['email']).then(
(loginResult) => {
if (loginResult.isCancelled) {
console.log('Login cancelled');
return false;
} else {
// Retrieve access token from FBSDK to be able to linkWith Parse
AccessToken.getCurrentAccessToken().then((data) => {
const facebookAccessToken = data.accessToken;
// Callback that will be called after FBSDK successfuly retrieves user email and id from FB
const responseEmailCallback = async (
error,
emailResult,
) => {
if (error) {
console.log('Error fetching data: ' + error.toString());
} else {
// Format authData to provide correctly for Facebook linkWith on Parse
const facebookId = emailResult.id;
const authData = {
id: facebookId,
access_token: facebookAccessToken,
};
let currentUser = await Parse.User.currentAsync();
return await currentUser
.linkWith('facebook', {
authData: authData,
})
.then(async (loggedInUser) => {
// logIn returns the corresponding ParseUser object
Alert.alert(
'Success!',
`User ${loggedInUser.get(
'username',
)} has successfully linked his Facebook account!`,
);
// To verify that this is in fact the current user, currentAsync can be used
currentUser = await Parse.User.currentAsync();
console.log(loggedInUser === currentUser);
return true;
})
.catch(async (linkWithError) => {
// Error can be caused by wrong parameters or lack of Internet connection
Alert.alert('Error!', linkWithError.message);
return false;
});
}
};
// Formats a FBSDK GraphRequest to retrieve user email and id
const emailRequest = new GraphRequest(
'/me',
{
accessToken: facebookAccessToken,
parameters: {
fields: {
string: 'email',
},
},
},
responseEmailCallback,
);
// Start the graph request, which will call the callback after finished
new GraphRequestManager().addRequest(emailRequest).start();
return true;
});
}
},
(error) => {
console.log('Login fail with error: ' + error);
return false;
},
);
} catch (error) {
Alert.alert('Error!', error.code);
return false;
}
};
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const doUserLinkFacebook = async function (): Promise<boolean> {
try {
// Login using the Facebook login dialog asking form email permission
return await LoginManager.logInWithPermissions(['email']).then(
(loginResult: object) => {
if (loginResult.isCancelled) {
console.log('Login cancelled');
return false;
} else {
// Retrieve access token from FBSDK to be able to linkWith Parse
AccessToken.getCurrentAccessToken().then((data: object) => {
const facebookAccessToken = data.accessToken;
// Callback that will be called after FBSDK successfuly retrieves user email and id from FB
const responseEmailCallback = async (
error: string,
emailResult: object,
) => {
if (error) {
console.log('Error fetching data: ' + error.toString());
} else {
// Format authData to provide correctly for Facebook linkWith on Parse
const facebookId: string = emailResult.id;
const authData: object = {
id: facebookId,
access_token: facebookAccessToken,
};
let currentUser: Parse.User = await Parse.User.currentAsync();
return await currentUser
.linkWith('facebook', {
authData: authData,
})
.then(async (loggedInUser: Parse.User) => {
// logIn returns the corresponding ParseUser object
Alert.alert(
'Success!',
`User ${loggedInUser.get(
'username',
)} has successfully linked his Facebook account!`,
);
// To verify that this is in fact the current user, currentAsync can be used
currentUser = await Parse.User.currentAsync();
console.log(loggedInUser === currentUser);
return true;
})
.catch(async (linkWithError: object) => {
// Error can be caused by wrong parameters or lack of Internet connection
Alert.alert('Error!', linkWithError.message);
return false;
});
}
};
// Formats a FBSDK GraphRequest to retrieve user email and id
const emailRequest = new GraphRequest(
'/me',
{
accessToken: facebookAccessToken,
parameters: {
fields: {
string: 'email',
},
},
},
responseEmailCallback,
);
// Start the graph request, which will call the callback after finished
new GraphRequestManager().addRequest(emailRequest).start();
return true;
});
}
},
(error: string) => {
console.log('Login fail with error: ' + error);
return false;
},
);
} catch (error: object) {
Alert.alert('Error!', error.code);
return false;
}
};
Assign this function to a Facebook button onPress
parameter on your home screen. 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 or sign up Parse users on React Native using Facebook FBSDK Login with react-native-fbsdk
. In the next guide, we will show you how to perform useful user queries.