Is there a way to programatically login to using AzureAD with Cypress on PKCE flow?

Question

I want to athenticate myself (React application) using cypress.js (https://www.cypress.io/). Is there a way to do it programatically with PKCE? As i was reading and looking into all examples - all of them are using implicit flow

I was trying to use solutions like https://www.npmjs.com/package/react-adal but with no success as it needs an implicit flow to be turned on I was trying this as well: https://xebia.com/blog/how-to-use-azure-ad-single-sign-on-with-cypress/ with no success

I expected to programatically signin inside cypress and save user info and access_token to sessionStorage to be able to perform another api calls

user_354971 · Answer

I have not found a way to do this programmatically with PKCE per se, but with the MSAL 2.0 library (@azure/msal-browser on npm) I was able to fill in the account cache ahead of time so it thought it was already logged in. The process looks like this:

With a cy.task, send a request to Azure AD using the ROPC flow to get the tokens.

const scopes = [
    'openid',
    'profile',
    'user.read',
    'email',
    'offline_access' // needed to get a refresh token
];
const formdata = new URLSearchParams({
    'grant_type': 'password',
    'scope': scopes.join(' '),
    'client_info': 1, // returns an extra token that MSAL needs
    'client_id': aadClientId,
    'client_secret': aadClientSecret,
    'username': aadUsername,
    'password': aadPassword,
});
const response = await fetch(`https://login.microsoft.com/${aadTenantId}/oauth2/v2.0/token`, {
    method: 'POST',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
    },
    body: formdata.toString(),
});
const tokens = await response.json();

Transform the tokens into the cache entries that MSAL wants (based on observing it in a real browser)

// The token tells us how many seconds until expiration;
// MSAL wants to know the timestamp of expiration.
const cachedAt = Math.round(new Date().getTime()/1000);
const expiresOn = cachedAt + tokens.expires_in;
const extendedExpiresOn = cachedAt + tokens.ext_expires_in;

// We can pull the rest of the data we need off of the ID token body
const id_token = JSON.parse(Buffer.from(tokens.id_token.split('.')[1], 'base64').toString('utf-8'));

const clientId = id_token.aud;
const tenantId = id_token.tid;
const userId = id_token.oid;
const name = id_token.name;
const username = id_token.preferred_username;

const environment = 'login.windows.net'; // ‍♂️
const homeAccountId = `${userId}.${tenantId}`;

const cacheEntries = {};

// client info
cacheEntries[`${homeAccountId}-${environment}-${tenantId}`] = JSON.stringify({
  authorityType: 'MSSTS',
  clientInfo: tokens.client_info,
  environment,
  homeAccountId,
  localAccountId: userId,
  name,
  realm: tenantId,
  username,
});

// access token
cacheEntries[`${homeAccountId}-${environment}-accesstoken-${clientId}-${tenantId}-${token.scope}`] = JSON.stringify({
  cachedAt: cachedAt.toString(),
  clientId,
  credentialType: "AccessToken",
  environment,
  expiresOn: expiresOn.toString(),
  extendedExpiresOn: extendedExpiresOn.toString(),
  homeAccountId,
  realm: tenantId,
  secret: tokens.access_token,
  target: tokens.scope,
});

// id token
cacheEntries[`${homeAccountId}-${environment}-idtoken-${clientId}-${tenantId}-`] = JSON.stringify({
  clientId,
  credentialType: "IdToken",
  environment,
  homeAccountId,
  realm: tenantId,
  secret: tokens.id_token,
});

// refresh token
cacheEntries[`${homeAccountId}-${environment}-refreshtoken-${clientId}--`] = JSON.stringify({
  clientId,
  credentialType: "RefreshToken",
  environment,
  homeAccountId,
  secret: tokens.refresh_token,
});

Use cy.window to store those in sessionStorage or localStorage, depending on how you have MSAL configured.

cy.task('login').then(cacheEntries => {
    cy.window().then(window => {
        for (let entry in cacheEntries) {
            window.sessionStorage.setItem(entry, cacheEntries[entry]);
        }
    });
});

It's super fragile and not very pretty, but it works! The user that Cypress logs in as needs MFA to be disabled, of course.

Is there a way to programatically login to using AzureAD with Cypress on PKCE flow?

1 Answers