GitHub sign-in in Firebase - Step-by-Step Execution

Process Flow - GitHub sign-in

User clicks 'Sign in with GitHub'

↓

Firebase triggers GitHub OAuth flow

↓

User enters GitHub credentials

↓

GitHub verifies credentials

↓

GitHub sends auth token to Firebase

↓

Firebase verifies token and signs in user

↓

User is signed in and app updates UI

The user clicks sign-in, Firebase starts GitHub login, user authenticates on GitHub, then Firebase signs in the user and updates the app.

Execution Sample

Firebase

const provider = new firebase.auth.GithubAuthProvider();
firebase.auth().signInWithPopup(provider)
  .then((result) => {
    console.log('User signed in:', result.user);
  })
  .catch((error) => console.error(error));

This code starts GitHub sign-in using a popup and logs the signed-in user or error.

Process Table

Step	Action	Firebase State	GitHub State	Result
1	User clicks 'Sign in with GitHub'	Idle	Idle	Start OAuth flow
2	Firebase opens GitHub login popup	Waiting for GitHub auth	Waiting for user input	Popup shown
3	User enters GitHub username and password	Waiting for GitHub auth	Verifying credentials	Credentials submitted
4	GitHub verifies credentials	Waiting for GitHub auth	Credentials valid	Token generated
5	GitHub sends token to Firebase	Verifying token	Token sent	Token received
6	Firebase verifies token and signs in user	User signed in	Token accepted	User authenticated
7	App updates UI to signed-in state	User signed in	Idle	UI updated
8	Process ends	User signed in	Idle	Sign-in complete

💡 User is signed in after Firebase verifies GitHub token and updates the app UI.

Status Tracker

Variable	Start	After Step 3	After Step 5	After Step 6	Final
firebaseState	Idle	Waiting for GitHub auth	Verifying token	User signed in	User signed in
gitHubState	Idle	Verifying credentials	Token sent	Token accepted	Idle
user	null	null	null	User object	User object

Key Moments - 3 Insights

Why does Firebase wait after opening the GitHub login popup?

Firebase waits for the user to enter credentials and GitHub to verify them, as shown in steps 2 and 3 of the execution_table.

What happens if GitHub credentials are incorrect?

Firebase will not receive a valid token, so the sign-in fails and an error is caught, stopping before step 6 in the execution_table.

When is the user object available in Firebase?

After Firebase verifies the GitHub token successfully at step 6, the user object becomes available.

Visual Quiz - 3 Questions

Look at the execution_table, what is the Firebase state at step 4?

A Idle

B Verifying token

C Waiting for GitHub auth

D User signed in

💡 Hint

Check the 'Firebase State' column at step 4 in the execution_table.

At which step does the user become signed in according to the execution_table?

A Step 5

B Step 6

C Step 3

D Step 7

💡 Hint

Look for when 'User signed in' appears in the 'Firebase State' column.

If the user closes the GitHub popup before entering credentials, which step would not occur?

A Step 3

B Step 2

C Step 6

D Step 7

💡 Hint

Refer to the 'Action' column and consider when user input is required.

Concept Snapshot

GitHub sign-in with Firebase:
1. Create GitHubAuthProvider.
2. Call signInWithPopup(provider).
3. User logs in via GitHub popup.
4. Firebase receives token and signs in user.
5. Handle success or error.
Use this flow to authenticate users easily.

Full Transcript

GitHub sign-in with Firebase starts when the user clicks the sign-in button. Firebase opens a popup for GitHub login. The user enters their GitHub username and password. GitHub verifies these credentials and sends a token back to Firebase. Firebase verifies this token and signs in the user. Finally, the app updates the UI to show the user is signed in. If any step fails, an error is returned. This flow ensures secure and simple authentication using GitHub accounts.

Practice

1. What is the main purpose of using GithubAuthProvider in Firebase authentication?

easy

A. To send emails to users

B. To store user data in Firebase database

C. To allow users to sign in using their GitHub accounts

D. To create a new GitHub repository

Solution

1. Step 1: Understand the role of GithubAuthProvider

   GithubAuthProvider is a Firebase class that helps connect Firebase authentication with GitHub accounts.

2. Step 2: Identify its main use

   It is used to let users sign in to your app using their GitHub login credentials.

3. Final Answer:

   To allow users to sign in using their GitHub accounts -> Option C

4. Quick Check:

   GithubAuthProvider = GitHub sign-in [OK]

Hint: GithubAuthProvider is for GitHub login only [OK]

Common Mistakes:

• Confusing authentication with database storage
• Thinking it sends emails
• Assuming it manages GitHub repositories

2. Which of the following is the correct way to create a GitHub auth provider instance in Firebase JavaScript SDK?

easy

A. const provider = new GitHubAuth();

B. const provider = new GitAuthProvider();

C. const provider = new GithubProvider();

D. const provider = new GithubAuthProvider();

Solution

1. Step 1: Recall the exact class name

   The Firebase SDK uses the class named GithubAuthProvider to create a GitHub auth provider.

2. Step 2: Match the syntax

   The correct syntax to create an instance is new GithubAuthProvider().

3. Final Answer:

   const provider = new GithubAuthProvider(); -> Option D

4. Quick Check:

   Correct class name and syntax = const provider = new GithubAuthProvider(); [OK]

Hint: Class name is exactly GithubAuthProvider with capital G and A [OK]

Common Mistakes:

• Misspelling the class name
• Using incorrect capitalization
• Using incomplete class names

3. What will happen when the following Firebase code runs successfully?

const provider = new GithubAuthProvider();
const result = await signInWithPopup(auth, provider);
console.log(result.user.email);

medium

A. It throws an error because signInWithPopup is not async

B. It logs the signed-in user's GitHub email address

C. It logs the user's GitHub password

D. It logs undefined because result has no user

Solution

1. Step 1: Understand signInWithPopup behavior

   This function opens a popup for GitHub sign-in and returns a user credential object on success.

2. Step 2: Access user email from result

   The result.user.email contains the authenticated user's email from GitHub.

3. Final Answer:

   It logs the signed-in user's GitHub email address -> Option B

4. Quick Check:

   signInWithPopup returns user info including email [OK]

Hint: signInWithPopup returns user info including email [OK]

Common Mistakes:

• Thinking password is accessible
• Assuming signInWithPopup is synchronous
• Expecting result.user to be undefined

4. You wrote this code but get an error: signInWithPopup(auth, provider) is not a function. What is the most likely cause?

medium

A. You forgot to import signInWithPopup from Firebase auth module

B. You did not create a GitHub account

C. You used signInWithRedirect instead of signInWithPopup

D. You did not enable GitHub sign-in in Firebase console

Solution

1. Step 1: Analyze the error message

   The error says signInWithPopup is not a function, meaning it is not recognized in the code.

2. Step 2: Check imports

   This usually happens if signInWithPopup was not imported from Firebase auth module properly.

3. Final Answer:

   You forgot to import signInWithPopup from Firebase auth module -> Option A

4. Quick Check:

   Missing import causes function not found error [OK]

Hint: Always import functions you use from Firebase SDK [OK]

Common Mistakes:

• Assuming GitHub account absence causes this error
• Confusing signInWithPopup with signInWithRedirect
• Ignoring Firebase console settings

5. You want to add GitHub sign-in to your Firebase app. Which steps must you complete before calling signInWithPopup(auth, provider)? Select the best sequence.

hard

A. Register OAuth app on GitHub, enable GitHub sign-in in Firebase console, create GithubAuthProvider instance

B. Create GithubAuthProvider instance, enable GitHub sign-in in Firebase console, register OAuth app on GitHub

C. Register OAuth app on GitHub, create GithubAuthProvider instance, enable GitHub sign-in in Firebase console

D. Enable GitHub sign-in in Firebase console, create GithubAuthProvider instance, register OAuth app on GitHub

Solution

1. Step 1: Register OAuth app on GitHub

   You must register your app on GitHub to get client ID and secret for authentication.

2. Step 2: Enable GitHub sign-in in Firebase console

   This step activates GitHub as a sign-in provider in your Firebase project.

3. Step 3: Create GithubAuthProvider instance in your code

   After setup, create the provider instance to use in signInWithPopup.

4. Final Answer:

   Register OAuth app on GitHub, enable GitHub sign-in in Firebase console, create GithubAuthProvider instance -> Option A

5. Quick Check:

   Setup order matters: GitHub app, Firebase console, then code [OK]

Hint: Register on GitHub, enable in Firebase, then code [OK]

Common Mistakes:

• Skipping enabling GitHub sign-in in Firebase
• Not registering OAuth app on GitHub
• Creating provider before setup steps