How to build a public Memberstack integration: Building the Auth Flow

Hey there, fellow JavaScript enthusiasts! Ready to dive into the world of Memberstack integrations? Today, we're going to walk through building a robust auth flow for your public integration. Buckle up, because we're about to make authentication a breeze!

Introduction

Memberstack is a powerful tool for managing memberships and subscriptions, and creating a public integration can really level up your app. The key to a smooth integration? A rock-solid auth flow. Let's get started!

Prerequisites

Before we jump in, make sure you've got:

• Your favorite JavaScript environment set up
• A Memberstack account with API credentials
• A burning desire to create awesome integrations

Setting up the project

First things first, let's get our project off the ground:

mkdir memberstack-integration
cd memberstack-integration
npm init -y
npm install express axios dotenv

Designing the Auth Flow

We'll be using OAuth 2.0 for our auth flow. It's like a secret handshake between your app and Memberstack. Here's the gist:

1. Your app asks Memberstack for permission
2. User logs in and approves
3. Memberstack gives you a special code
4. You trade that code for access tokens
5. Use those tokens to make API requests

Implementing the Auth Flow

Initiating the auth request

Let's kick things off by creating an authorization URL:

const authUrl = `https://auth.memberstack.com/oauth2/authorize?client_id=${CLIENT_ID}&redirect_uri=${REDIRECT_URI}&response_type=code&scope=read:members`;

app.get('/auth', (req, res) => {
  res.redirect(authUrl);
});

Handling the callback

After the user approves, Memberstack will send them back to your app with a code. Let's grab it:

app.get('/callback', async (req, res) => {
  const { code } = req.query;
  
  try {
    const tokenResponse = await axios.post('https://auth.memberstack.com/oauth2/token', {
      grant_type: 'authorization_code',
      client_id: CLIENT_ID,
      client_secret: CLIENT_SECRET,
      code,
      redirect_uri: REDIRECT_URI
    });

    const { access_token, refresh_token } = tokenResponse.data;
    // Store these tokens securely!
    
    res.send('Authentication successful!');
  } catch (error) {
    console.error('Error exchanging code for tokens:', error);
    res.status(500).send('Authentication failed');
  }
});

Token management

Now that we've got our tokens, let's keep them safe and fresh:

function storeTokens(accessToken, refreshToken) {
  // Use a secure method to store these, like encrypted cookies or a secure database
}

async function refreshAccessToken(refreshToken) {
  try {
    const response = await axios.post('https://auth.memberstack.com/oauth2/token', {
      grant_type: 'refresh_token',
      client_id: CLIENT_ID,
      client_secret: CLIENT_SECRET,
      refresh_token: refreshToken
    });
    
    return response.data.access_token;
  } catch (error) {
    console.error('Error refreshing token:', error);
    throw error;
  }
}

Making authenticated requests

Time to put those tokens to work:

async function getMemberInfo(accessToken) {
  try {
    const response = await axios.get('https://api.memberstack.com/v1/members/me', {
      headers: { Authorization: `Bearer ${accessToken}` }
    });
    return response.data;
  } catch (error) {
    if (error.response && error.response.status === 401) {
      // Time to refresh that token!
      const newAccessToken = await refreshAccessToken(refreshToken);
      // Retry the request with the new token
    }
    throw error;
  }
}

Error handling and edge cases

Always be prepared for the unexpected:

function handleAuthError(error) {
  if (error.response) {
    switch (error.response.status) {
      case 400:
        console.error('Bad request. Check your parameters.');
        break;
      case 401:
        console.error('Unauthorized. Token might be invalid or expired.');
        break;
      // Add more cases as needed
      default:
        console.error('An unexpected error occurred:', error.message);
    }
  } else {
    console.error('Network error:', error.message);
  }
}

Security considerations

Keep it locked down, folks:

• Use CSRF tokens to prevent cross-site request forgery
• Never store tokens in local storage - use HTTP-only cookies or server-side storage
• Always use HTTPS for all auth-related requests

Testing the auth flow

Before you ship it, test it:

1. Try logging in with valid credentials
2. Attempt to use an expired token
3. Test token refresh functionality
4. Simulate network errors and API downtime

Consider setting up automated tests with Jest or Mocha to keep your auth flow in check.

Conclusion

And there you have it! You've just built a robust auth flow for your Memberstack integration. Remember, authentication is the gateway to your app's kingdom, so treat it with care. Keep iterating, keep securing, and most importantly, keep building awesome stuff!

Additional resources

Want to dive deeper? Check out:

• Memberstack API docs
• OAuth 2.0 RFC

Now go forth and integrate with confidence! Happy coding! 🚀