5a. Session verification in an API call

Implement session verification in API calls to securely fetch user session data.

For this guide, we will assume that we want an API /api/user GET which returns the current session information.

1. Create a new file /pages/api/user.ts

2. Call the supertokens.init function

Remember that whenever we want to use any functions from the supertokens-node lib, we have to call the supertokens.init function at the top of that serverless function file.

import supertokens from "supertokens-node";
import { backendConfig } from "../../../config/backendConfig";

supertokens.init(backendConfig());

3. Call the verifySession session function

import { superTokensNextWrapper } from "supertokens-node/nextjs";
import { verifySession } from "supertokens-node/recipe/session/framework/express";
import supertokens from "supertokens-node";
import { backendConfig } from "../../../config/backendConfig";
import NextCors from "nextjs-cors";

supertokens.init(backendConfig());

export default async function user(req: any, res: any) {
  // NOTE: We need CORS only if we are querying the APIs from a different origin
  await NextCors(req, res, {
    methods: ["GET", "HEAD", "PUT", "PATCH", "POST", "DELETE"],
    origin: "<YOUR_WEBSITE_DOMAIN>",
    credentials: true,
    allowedHeaders: ["content-type", ...supertokens.getAllCORSHeaders()],
  });

  // we first verify the session
  await superTokensNextWrapper(
    async (next) => {
      return await verifySession()(req, res, next);
    },
    req,
    res,
  );
  // if it comes here, it means that the session verification was successful

  return res.json({
    note: "Fetch any data from your application for authenticated user after using verifySession middleware",
    userId: req.session.getUserId(),
    sessionHandle: req.session.getHandle(),
    userDataInAccessToken: req.session.getAccessTokenPayload(),
  });
}

• If no session exists, the API will return a 401 error to the client. In this case, the code return res.json will not be executed at all.
• In case the session does exist, req.session can be used to get session information. Learn more about this object here.