client.md

Client use case

Example

Code available here

Create a node module:

mkdir project
cd project
npm init -y
npm i express node-expose-sspi

Test Server

First we need an HTTP server that wants to authenticate with a Negotiate protocol (NTLM and Kerberos). By chance, we can have one with node-expose-sspi.

Note: If you have already your own server, you don't need this one.

Create the server.js:

const express = require('express');
const { sso } = require('node-expose-sspi');

const app = express();

app.use(sso.auth());

app.use((req, res) => {
  res.json({
    sso: req.sso.user.displayName,
  });
});

app.listen(3000, () =>
  console.log('Server started on port 3000')
);

Client

Create an client.js script with the following content:

const { sso } = require('node-expose-sspi');

(async () => {
  try {
    const response = await new sso.Client().fetch('http://localhost:3000');
    const json = await response.json();
    console.log('json: ', json);
  } catch (e) {
    console.error(e);
  }
})();

Running

You need a first terminal for the server, and second one for running the client.

First Terminal

node server.js

The script output:

Server started on port 3000

Second terminal

node client.js

You should have this output:

json:  { sso: 'Jean-Louis GUÉNÉGO' }

Of course, this will be your windows account display name. Not mine 😄

The client object

sso.Client is a Javascript class with fetch method.

The sso.Client.fetch method exactly works as the node-fetch utility, which is completed by:

• Negotiate, Kerberos, NTLM protocol
• Cookies management

The client can be configured:

• setSSP(): set NTLM, Kerberos, or Negotiate.
• setCredentials() : set the credentials of another user.
• setTargetName(): set the Service Principal Name to be what you need exactly. Useful for doing Kerberos on localhost for instance. Browsers cannot do that.

Thanks to the node-fetch project.

More information on the fetch API on the MDN website.

Author

Jean-Louis GUENEGO jlguenego@gmail.com