In this example, we will look at how to add Facebook Login to Your Cognito User Pool using SST.

Requirements

Create an SST app

Let’s start by creating an SST app.

$ npx create-sst@latest --template=starters/typescript-starter api-oauth-facebook
$ cd api-oauth-facebook
$ npm install

By default, our app will be deployed to an environment (or stage) called dev and the us-east-1 AWS region. This can be changed in the sst.json in your project root.

{
  "name": "api-oauth-facebook",
  "region": "us-east-1",
  "main": "stacks/index.ts"
}

Project layout

An SST app is made up of two parts.

  1. stacks/ — App Infrastructure

    The code that describes the infrastructure of your serverless app is placed in the stacks/ directory of your project. SST uses AWS CDK, to create the infrastructure.

  2. services/ — App Code

    The code that’s run when your API is invoked is placed in the services/ directory of your project.

Setting up the Auth

First, let’s create a Cognito User Pool to store the user info using the Auth construct

Replace the stacks/MyStack.ts with the following.

import * as cognito from "aws-cdk-lib/aws-cognito";
import {
  Api,
  Auth,
  StackContext,
  ViteStaticSite,
} from "@serverless-stack/resources";

export function MyStack({ stack, app }: StackContext) {
  // Create auth
  const auth = new Auth(stack, "Auth", {
    cdk: {
      userPoolClient: {
        supportedIdentityProviders: [
          cognito.UserPoolClientIdentityProvider.FACEBOOK,
        ],
        oAuth: {
          callbackUrls: [
            app.stage === "prod"
              ? "prodDomainNameUrl"
              : "http://localhost:3000",
          ],
          logoutUrls: [
            app.stage === "prod"
              ? "prodDomainNameUrl"
              : "http://localhost:3000",
          ],
        },
      },
    },
  });
}

This creates a Cognito User Pool; a user directory that manages users. We’ve configured the User Pool to allow users to login with their Facebook account and added the callback and logout URLs.

Note, we haven’t yet set up Facebook OAuth with our user pool, we’ll do it next.

Setting up Facebook OAuth

Now let’s add Facebook OAuth for our serverless app, to do so we need to create a Facebook User Pool identity provider and link it with the user pool we created above.

Sign In with your Facebook credentials in the developer console and from the My Apps menu, choose Create App.

Create app Facebook console

Choose Consumer as app type and hit Next.

Facebook app type

Give your Facebook app a name and click Create App.

Basic info to create app

On the left navigation bar, choose Settings and then Basic.

Create a .env.local file in the root and add your Facebook App ID and App secret.

FACEBOOK_APP_ID=<YOUR_FACEBOOK_APP_ID>
FACEBOOK_APP_SECRET=<YOUR_FACEBOOK_APP_SECRET>

Basic settings view

Add this below the Auth definition in stacks/MyStack.ts.

// Throw error if App ID & secret are not provided
if (!process.env.FACEBOOK_APP_ID || !process.env.FACEBOOK_APP_SECRET)
  throw new Error("Please set FACEBOOK_APP_ID and FACEBOOK_APP_SECRET");

// Create a Facebook OAuth provider
const provider = new cognito.UserPoolIdentityProviderFacebook(
  stack,
  "Facebook",
  {
    clientId: process.env.FACEBOOK_APP_ID,
    clientSecret: process.env.FACEBOOK_APP_SECRET,
    userPool: auth.cdk.userPool,
    attributeMapping: {
      email: cognito.ProviderAttribute.FACEBOOK_EMAIL,
      givenName: cognito.ProviderAttribute.FACEBOOK_NAME,
    },
  }
);

// attach the created provider to our userpool
auth.cdk.userPoolClient.node.addDependency(provider);

This creates a Facebook identity provider with the given scopes and links the created provider to our user pool and Facebook user’s attributes will be mapped to the User Pool user.

Now let’s associate a Cognito domain to the user pool, which can be used for sign-up and sign-in webpages.

Add below code in stacks/MyStack.ts.

// Create a cognito userpool domain
const domain = auth.cdk.userPool.addDomain("AuthDomain", {
  cognitoDomain: {
    domainPrefix: `${app.stage}-fb-demo-auth-domain`,
  },
});

Note, the domainPrefix need to be globally unique across all AWS accounts in a region.

Setting up the API

Replace the Api definition with the following in stacks/MyStacks.ts.

// Create a HTTP API
const api = new Api(stack, "Api", {
  authorizers: {
    userPool: {
      type: "user_pool",
      userPool: {
        id: auth.userPoolId,
        clientIds: [auth.userPoolClientId],
      },
    },
  },
  defaults: {
    authorizer: "userPool",
  },
  routes: {
    "GET /private": "functions/private.handler",
    "GET /public": {
      function: "functions/public.handler",
      authorizer: "none",
    },
  },
});

// Allow authenticated users invoke API
auth.attachPermissionsForAuthUsers([api]);

We are creating an API here using the Api construct. And we are adding two routes to it.

GET /private
GET /public

By default, all routes have the authorization type JWT. This means the caller of the API needs to pass in a valid JWT token. The GET /private route is a private endpoint. The GET /public is a public endpoint and its authorization type is overridden to NONE.

Let’s install the npm packages we are using here.

Update the package.json in the root.

...
"aws-cdk-lib": "2.20.0",
...

You can find the latest CDK versions supported by SST in our releases.

Adding function code

Let’s create two functions, one handling the public route, and the other for the private route.

Add a services/functions/public.ts.

export async function handler() {
  return {
    statusCode: 200,
    body: "Hello, stranger!",
  };
}

Add a services/functions/private.ts.

import { APIGatewayProxyHandlerV2WithJWTAuthorizer } from "aws-lambda";

export const handler: APIGatewayProxyHandlerV2WithJWTAuthorizer = async (
  event
) => {
  return {
    statusCode: 200,
    body: `Hello ${event.requestContext.authorizer.jwt.claims.sub}!`,
  };
};

Setting up our React app

To deploy a React app to AWS, we’ll be using the SST ViteStaticSite construct.

Replace the stack.addOutputs({ call with the following.

// Create a React Static Site
const site = new ViteStaticSite(stack, "Site", {
  path: "frontend",
  environment: {
    VITE_APP_COGNITO_DOMAIN: domain.domainName,
    VITE_APP_API_URL: api.url,
    VITE_APP_REGION: app.region,
    VITE_APP_USER_POOL_ID: auth.userPoolId,
    VITE_APP_IDENTITY_POOL_ID: auth.cognitoIdentityPoolId,
    VITE_APP_USER_POOL_CLIENT_ID: auth.userPoolClientId,
  },
});

// Show the endpoint in the output
stack.addOutputs({
  api_url: api.url,
  auth_client_id: auth.userPoolClientId,
  auth_domain: `https://${domain.domainName}.auth.${app.region}.amazoncognito.com`
  site_url: site.url,
});

The construct is pointing to where our React.js app is located. We haven’t created our app yet but for now, we’ll point to the frontend directory.

We are also setting up build time React environment variables with the endpoint of our API. The ViteStaticSite allows us to set environment variables automatically from our backend, without having to hard code them in our frontend.

We are going to print out the resources that we created for reference.

Creating the frontend

Run the below commands in the root to create a basic react project.

$ npx create-vite@latest frontend --template react
$ cd frontend
$ npm install

This sets up our React app in the frontend/ directory. Recall that, earlier in the guide we were pointing the ViteStaticSite construct to this path.

We also need to load the environment variables from our SST app. To do this, we’ll be using the @serverless-stack/static-site-env package.

Install the static-site-env package by running the following in the frontend/ directory.

$ npm install @serverless-stack/static-site-env --save-dev

We need to update our start script to use this package.

Replace the dev script in your frontend/package.json.

"dev": "vite"

With the following:

"dev": "sst-env -- vite"

Starting your dev environment

SST features a Live Lambda Development environment that allows you to work on your serverless apps live.

$ npm start

The first time you run this command it’ll take a couple of minutes to deploy your app and a debug stack to power the Live Lambda Development environment.

===============
 Deploying app
===============

Preparing your SST app
Transpiling source
Linting source
Deploying stacks
manitej-api-oauth-facebook-my-stack: deploying...

 ✅  manitej-api-oauth-facebook-my-stack


Stack manitej-api-oauth-facebook-my-stack
  Status: deployed
  Outputs:
    api_url: https://v0l1zlpy5f.execute-api.us-east-1.amazonaws.com
    auth_client_id: 253t1t5o6jjur88nu4t891eac2
    auth_domain: https://manitej-fb-demo-auth-domain.auth.us-east-1.amazoncognito.com
    site_url: https://d1567f41smqk8b.cloudfront.net

On the left navigation bar, click on Add product.

In the Add products to your app section choose Facebook Login and hit Set up.

Add products to your app

Click on Web.

Facebook quickstart screen

Under Site URL, type your user pool domain with the /oauth2/idpresponse endpoint.

Enter site URL screen

Type your user pool domain into App Domains.

Facebook app domains screen

Type your redirect URL into Valid OAuth Redirect URIs. It will consist of your user pool domain with the /oauth2/idpresponse endpoint.

Redirect URLs screen

The api_url is the API we just created. While the site_url is where our React app will be hosted. For now, it’s just a placeholder website.

Let’s test our endpoint with the SST Console. The SST Console is a web based dashboard to manage your SST apps. Learn more about it in our docs.

Go to the API tab and click Send button of the GET /public to send a GET request.

Note, The API explorer lets you make HTTP requests to any of the routes in your Api construct. Set the headers, query params, request body, and view the function logs with the response.

API explorer invocation response

You should see a Hello, stranger! in the response body.

And if you try for GET /private, you will see {"message":"Unauthorized"}.

Adding AWS Amplify

To use our AWS resources on the frontend we are going to use AWS Amplify.

Note, to know more about configuring Amplify with SST check this chapter.

Run the below command to install AWS Amplify in the frontend/ directory.

npm install aws-amplify

Replace frontend/src/main.jsx with below code.

/* eslint-disable no-undef */
import React from "react";
import ReactDOM from "react-dom";
import "./index.css";
import App from "./App";
import Amplify from "aws-amplify";

Amplify.configure({
  Auth: {
    region: import.meta.env.VITE_APP_REGION,
    userPoolId: import.meta.env.VITE_APP_USER_POOL_ID,
    userPoolWebClientId: import.meta.env.VITE_APP_USER_POOL_CLIENT_ID,
    mandatorySignIn: false,
    oauth: {
      domain: `${
        import.meta.env.VITE_APP_COGNITO_DOMAIN +
        ".auth." +
        import.meta.env.VITE_APP_REGION +
        ".amazoncognito.com"
      }`,
      redirectSignIn: "http://localhost:3000", // Make sure to use the exact URL
      redirectSignOut: "http://localhost:3000", // Make sure to use the exact URL
      responseType: "token", // or 'token', note that REFRESH token will only be generated when the responseType is code
    },
  },
  API: {
    endpoints: [
      {
        name: "api",
        endpoint: import.meta.env.VITE_APP_API_URL,
        region: import.meta.env.VITE_APP_REGION,
      },
    ],
  },
});

ReactDOM.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>,
  document.getElementById("root")
);

Adding login UI

Replace frontend/src/App.jsx with below code.

import { Auth, API } from "aws-amplify";
import React, { useState, useEffect } from "react";

const App = () => {
  const [user, setUser] = useState(null);
  const [loading, setLoading] = useState(true);

  const getUser = async () => {
    const user = await Auth.currentUserInfo();
    if (user) setUser(user);
    setLoading(false);
  };

  const signIn = async () =>
    await Auth.federatedSignIn({
      provider: "Facebook",
    });

  const signOut = async () => await Auth.signOut();

  const publicRequest = async () => {
    const response = await API.get("api", "/public");
    alert(JSON.stringify(response));
  };

  const privateRequest = async () => {
    try {
      const response = await API.get("api", "/private", {
        headers: {
          Authorization: `Bearer ${(await Auth.currentSession())
            .getAccessToken()
            .getJwtToken()}`,
        },
      });
      alert(JSON.stringify(response));
    } catch (error) {
      alert(error);
    }
  };

  useEffect(() => {
    getUser();
  }, []);

  if (loading) return <div className="container">Loading...</div>;

  return (
    <div className="container">
      <h2>SST + Cognito + Facebook OAuth + React</h2>
      {user ? (
        <div className="profile">
          <p>Welcome {user.attributes.given_name}!</p>
          <p>{user.attributes.email}</p>
          <button onClick={signOut}>logout</button>
        </div>
      ) : (
        <div>
          <p>Not signed in</p>
          <button onClick={signIn}>login</button>
        </div>
      )}
      <div className="api-section">
        <button onClick={publicRequest}>call /public</button>
        <button onClick={privateRequest}>call /private</button>
      </div>
    </div>
  );
};

export default App;

Replace frontend/src/index.css with the below styles.

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto",
    "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans",
    "Helvetica Neue", sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

code {
  font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New",
    monospace;
}

.container {
  width: 100%;
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

button {
  width: 120px;
  padding: 10px;
  border: none;
  border-radius: 4px;
  background-color: #000;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
}

.profile {
  border: 1px solid #ccc;
  padding: 20px;
  border-radius: 4px;
}
.api-section {
  width: 100%;
  margin-top: 20px;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 10px;
}

.api-section > button {
  background-color: darkorange;
}

Let’s start our frontend in development environment.

In the frontend/ directory run.

npm run dev

Open up your browser and go to http://localhost:3000.

Browser view of localhost

Note, if you get a blank page add this <script> in frontend/index.html.

<script>
  if (global === undefined) {
    var global = window;
    var global = alert;
  }
</script>

There are 2 buttons that invokes the endpoints we created above.

The call /public button invokes GET /public route using the publicRequest method we created in our frontend.

Similarly, the call /private button invokes GET /private route using the privateRequest method.

When you’re not logged in and try to click the buttons, you’ll see responses like below.

public button click without login

private button click without login

Once you click on login, you’re asked to login through your Facebook account.

login button click Facebook login screen

Once it’s done you can check your info.

current logged in user info

Now that you’ve authenticated repeat the same steps as you did before, you’ll see responses like below.

public button click with login

private button click with login

As you can see the private route is only working while we are logged in.

Deploying your API

To wrap things up we’ll deploy our app to prod.

$ npx sst deploy --stage prod

This allows us to separate our environments, so when we are working in dev, it doesn’t break the app for our users.

Once deployed, you should see something like this.

 ✅  prod-api-oauth-facebook-my-stack


Stack prod-api-oauth-facebook-my-stack
  Status: deployed
  Outputs:
    api_url: https://ck198mfop1.execute-api.us-east-1.amazonaws.com
    auth_client_id: 875t1t5o6jjur88jd4t891eat5
    auth_domain: https://prod-fb-demo-auth-domain.auth.us-east-1.amazoncognito.com
    site_url: https://c1767f41smqkh7.cloudfront.net

Note, if you get any error like 'request' is not exported by __vite-browser-external, imported by node_modules/@aws-sdk/credential-provider-imds/dist/es/remoteProvider/httpRequest.js replace vite.config.js with below code.

import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";

// https://vitejs.dev/config/
export default defineConfig({
  ...
  resolve: {
    alias: {
      "./runtimeConfig": "./runtimeConfig.browser",
    },
  },
  ...
});

Cleaning up

Finally, you can remove the resources created in this example using the following command.

$ npx sst remove

And to remove the prod environment.

$ npx sst remove --stage prod

Conclusion

And that’s it! You’ve got a brand new serverless API authenticated with Facebook. A local development environment, to test. And it’s deployed to production as well, so you can share it with your users. Check out the repo below for the code we used in this example. And leave a comment if you have any questions!