Session Migration

In this section we will go over how to migrate your user sessions from you previous authentication provider to SuperTokens.

There are two steps to this process

Adding a new /migrate-session API to your backend which will create a new SuperTokens session
Calling the /migrate-session API on your frontend to create a new SuperTokens session and revoke your old session.

Flow#

Backend Changes:#

Create an API on your backend, this will be called by the frontend to migrate a user's existing session to a SuperTokens session:

Backend changes

import express from "express";
import Session from "supertokens-node/recipe/session";

let app = express();

app.post("/migrate-session", async (req, res) => {

    // extract the access token from the request object
    if(req.headers.authorization !== undefined){
        let access_token = req.headers.authorization.split("Bearer ")[1];

        // verify the access token and retrieve the old userId
        let customUserId = await verifyAccessTokenAndRetriveUserId(access_token);

        // create a new SuperTokens session using the customUserId
        // the createNewSession function will attach the SuperTokens session cookies to the response object.
        await Session.createNewSession(res, customUserId)
        res.send({
            status: "OK"
        })
    }

    // handle access_token not present in request
    
})

async function verifyAccessTokenAndRetriveUserId(access_token: string): Promise<string> {
    // verify the access_token and return the decoded userId
    return "...";
}

important

Verifying the access token will require you to access your previous providers JWKS endpoint, which means that you will have to continue to use your previous auth provider even after switching to SuperTokens.

If you want to immediately stop querying your previous authentication provider you can use the JWKS public keys and provide them as a secret to the JWT verification function. You can follow our guide on how to do this.

Frontend Changes:#

On your frontend, on page load, check if a session with your previous authentication provider exists.
If a session exists send a request to the /migrate-session API with the access token to create a new SuperTokens session.
Revoke the old session.

Frontend changes

import axios from "axios";

// You will need to add the SuperTokens axios interceptor so cookies are correctly set.
import Session from "supertokens-web-js/recipe/session";
Session.addAxiosInterceptors(axios)

// Call this function on page load
async function migrateUserSessions() {
    let apiDomain = "...";
    // On page load retrieve the users access token if a session exists
    let accessToken = await getAccessTokenFromOldProvider()

    if (accessToken !== undefined) {

        // send a request to your migrate session endpoint with the bearer token
        await axios.post(`${apiDomain}/migrate-session`, {
            headers: {
                "Authorization": `Bearer ${accessToken}`
            }
        })
        await revokeSessionFromOldProvider()
    }
}

async function getAccessTokenFromOldProvider(): Promise<string | undefined> {
    // Check if a session with your your previous provider exists and return the access_token. Return undefined otherwise
    return "..."
}

async function revokeSessionFromOldProvider() {
    // Revoke the session associated with the previous provider
}