Set up Lambda

1. Create a new lambda

• Click "Create Function" in the AWS Lambda dashboard, enter the function name and runtime, and create your Lambda function.

2. Link lambda layer with the lambda function

• Scroll to the bottom and look for the Layers tab. Click on Add a layer

• Select Custom Layer and then select the layer we created in the first step:

3. Create a backend config file

Using the editor provided by AWS, create a new config file and write the following code:

App Info

Adjust these values based on the application that you are trying to configure. To learn more about what each field means check the references page.

Application NameThis is the URL of your app's API server.

API DomainThis is the URL of your app's API server.

API Base PathSuperTokens will expose it's APIs scoped by this base API path.

Website DomainThis is the URL of your website.

Website Base PathThe path where the login UI will be rendered

config.mjs

import EmailPassword from "supertokens-node/recipe/emailpassword";
import Session from "supertokens-node/recipe/session";

export function getBackendConfig() {
  return {
    framework: "awsLambda",
    supertokens: {
      connectionURI: "<CORE_API_ENDPOINT>",
      // apiKey: "<YOUR_API_KEY>",
    },
    appInfo: {
      // learn more about this on https://supertokens.com/docs/references/app-info
      appName: "<YOUR_APP_NAME>",
      apiDomain: "<YOUR_API_DOMAIN>",
      websiteDomain: "<YOUR_WEBSITE_DOMAIN>",
      apiBasePath: "/auth",
      websiteBasePath: "/auth",
      apiGatewayPath: "/dev"
    },
    recipeList: [
      EmailPassword.init(),
      Session.init(),
    ],
    isInServerlessEnv: true,
  }
}

important

In the above code, notice the extra config of apiGatewayPath that was added to the appInfo object. The value of this should be whatever you have set as the value of your AWS stage which scopes your API endpoints. For example, you may have a stage name per dev environment:

• One for development (/dev).
• One for testing (/test).
• One for prod (/prod).

So the value of apiGatewayPath should be set according to the above based on the env it's running under.

You also need to change the apiBasePath on the frontend config to append the stage to the path. For example, if the frontend is query the development stage and the value of apiBasePath is /auth, you should change it to /dev/auth.

note

You may edit the apiBasePath and apiGatewayPath value later if you haven't setup the API Gateway yet.

4. Add the SuperTokens auth middleware

Using the editor provided by AWS, create/replace the handler file contents with the following code:

index.mjs

import supertokens from "supertokens-node";
import { middleware } from "supertokens-node/framework/awsLambda";
import { getBackendConfig } from "./config.mjs";
import middy from "@middy/core";
import cors from "@middy/http-cors";

supertokens.init(getBackendConfig());

export const handler = middy(
    middleware((event) => {
      // SuperTokens middleware didn't handle the route, return your custom response
      return {
        body: JSON.stringify({
            msg: "Hello!",
        }),
        statusCode: 200,
      };
    })
)
    .use(
        cors({
            origin: getBackendConfig().appInfo.websiteDomain,
            credentials: true,
            headers: ["Content-Type", ...supertokens.getAllCORSHeaders()].join(", "),
            methods: "OPTIONS,POST,GET,PUT,DELETE",
        })
    )
    .onError((request) => {
        throw request.error;
    });

important

Since, we are using esm imports, we will need to set NODE_OPTIONS="--experimental-specifier-resolution=node" flag in the lambda environment variables. See the Node.js documentation for more information.