Technical Articles

Denys van Kempen

Posted on October 5, 2020 4 minute read

Authentication using XSUAA | Migrating from the Neo Environment to the Multi-Cloud Foundation

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This blog post series is about developing applications in a multi-cloud environment.

Cloud Foundry, Neo, and multicloud environments

For the end-to-end hands-on tutorial example, see

End-to-End Tutorial | Developing Secure Applications on the SAP Cloud Platform Cloud Foundry Runtime

For the step-by-step series, visit

Cloud Foundry, UAA, and XSUAA
Business Logic App
Service Instance (SAP HANA Cloud)
Application Router
Authentication using XSUAA <<< this post
Authorization using XSUAA
Multi-target applications (MTA)
Application Runtime (Appendix)

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Thanks!

Hands-On Tutorials

Developing Secure Applications on the SAP Cloud Platform

In this blog series, we explore authentication and authorisation using XSUAA in the SAP Cloud Platform, Cloud Foundry environment.

In this blog, we cover how we can authenticate access to our business logic app.

Tutorial Video

In this sixth video of the series, we explore authentication using XSUAA service with some code changes to the business logic of our services app.

Sample Code

As before, we continue with the (slightly modified) sample code from SAP Cloud Platform documentation:

You can download the sample code from repository

github.com/dvankempen/XSUAA

Appendix

For more detailed information about the SAP Cloud Platform trial environment, Cloud Foundry buildpacks, dependencies declarations, attributes, Diego cells and more, see the “appendix” blog

Platform Internals

Business Logic App

Application Descriptor | Package.json

For authorisation, we are going to use passport, a generic Node.js module, together with the XS Advanced Container Security API for Node.js.

Passport is Express-compatible authentication middleware for Node.js (as documented) and we use xsenv to read the application configurations for bound services and certificates in the SAP Cloud Platform Cloud Foundry environment, and xssec for the security configuration.

As documented

To make a connection to SAP HANA Cloud, we use the HDB (SAP HANA) convenience package with xsenv to lookup the bound hana service for credentials.

@sap/hdbext

npm i passport
npm i @sap/xssec
npm i @sap/xsenv

This results in the following dependencies for our package.json file.

"dependencies": {
    ...
    "@sap/xsenv": "^3.0.0",
    "@sap/xssec": "^3.0.10",
    "passport": "^0.4.1"
  },

Business Logic | Server.js

To the business logic, we change the getServices call to both the hdicontainer-1 service and myxsuaa services created previously.

We initialise password with JWT authentication using xssec. This is boilerplate code from

@sap/xssec

The /xsuaa path returns the authenticated user id (platform) and the user from the hana environment.

const xsenv = require('@sap/xsenv');
var services = xsenv.getServices({ hana:'hdicontainer-1', uaa:'myxsuaa' });

const passport = require('passport');
var JWTStrategy = require('@sap/xssec').JWTStrategy;
passport.use(new JWTStrategy(services.uaa));
app.use(passport.initialize());
app.use(passport.authenticate('JWT', { session: false }));

// Get environment using passport, xsenv, and xssec
app.get('/xsuaa', function (req, res, next) {
  res.send('Application user: ' + req.user.id + '<br>' + 'HANA user: ' + services.hana.user);
});

Application Router

We continue with the approuter as configured in the previous blog where we installed the @sap/approuter package and defined the route(s) in the xs-app.json file.

Approuter (previous blog)

User Interface | Index.html

To the home page of the approuter add a line to point to /xsuaa.

<html>
<head>
  <title>XSUAA Tutorial</title>
</head>
<body>
  <h1>XSUAA Tutorial</h1>
  <a href="/myapp/"> get('/')</a></br>
  <a href="/myapp/xsuaa">get('/xsuaa'</a></br>
  <a href="/myapp/hana">get('/hana')</a>
</body>
</html>

App Router Description | xs-app.json

The router will forward any request to /myapp to the destination with name “myapp” (no changes).

This destination is defined in the manifest (no changes).

App Deployment

Command Line

To deploy the app run the cf push command. No changes were made to the manifest.

# housekeeping
cf d[elete] myapp -r -f
# deploying
cf push
# running
cf a[pps]

Unauthorized

When we now access the business logic app directly we get an HTTP 403 Unauthorized message.

App Router

When we access the app router, we are first prompted to provide the credentials to our identity provider, here SAP ID services.

We are then presented with the home page (index.html) of the Application Router.

Selecting the links makes a call the business logic app. Note that we remain connected to the Application Router.

Please Proceed

In the next blog we explain how we can configure our app for authorization.

Authorization using XSUAA

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