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cas-authentication

Express CAS Authentication

This is a CAS authentication library designed to be used with an Express server.

It provides two middleware functions for controlling access to routes:

  • bounce: Redirects an unauthenticated client to the CAS login page and then back to the requested page.
  • block: Completely denies access to an unauthenticated client and returns a 401 response.

It also provides two route endpoint functions:

  • bounce_redirect: Acts just like bounce but once the client is authenticated they will be redirected to the provided returnTo query parameter.
  • logout: De-authenticates the client with the Express server and then redirects them to the CAS logout page.

Installation

npm install cas-authentication

Setup

var CASAuthentication = require('cas-authentication');
 
var cas = new CASAuthentication({
    cas_url         : 'https://my-cas-host.com/cas',
    service_url     : 'https://my-service-host.com',
    cas_version     : '3.0',
    renew           : false,
    is_dev_mode     : false,
    dev_mode_user   : '',
    dev_mode_info   : {},
    session_name    : 'cas_user',
    session_info    : 'cas_userinfo',
    destroy_session : false
});

Options

Name Type Description Default
cas_url string The URL of the CAS server. (required)
service_url string The URL of the application which is registered with the CAS server as a valid service. (required)
cas_version "1.0"|"2.0|"3.0"|"saml1.1" The CAS protocol version. "3.0"
renew boolean If true, an unauthenticated client will be required to login to the CAS system regardless of whether a single sign-on session exists. false
is_dev_mode boolean If true, no CAS authentication will be used and the session CAS variable will be set to whatever user is specified as dev_mode_user. false
dev_mode_user string The CAS user to use if dev mode is active. ""
dev_mode_info Object The CAS user information to use if dev mode is active. {}
session_name string The name of the session variable that will store the CAS user once they are authenticated. "cas_user"
session_info string The name of the session variable that will store the CAS user information once they are authenticated. If set to false (or something that evaluates as false), the additional information supplied by the CAS will not be forwarded. This will not work with CAS 1.0, as it does not support additional user information. false
destroy_session boolean If true, the logout function will destroy the entire session upon CAS logout. Otherwise, it will only delete the session variable storing the CAS user. false

Usage

var app = require('express')();
var session = require('express-session');
var CASAuthentication = require('cas-authentication');
 
// Set up an Express session, which is required for CASAuthentication. 
app.use( session({
    secret            : 'super secret key',
    resave            : false,
    saveUninitialized : true
}));
 
// Create a new instance of CASAuthentication. 
var cas = new CASAuthentication({
    cas_url     : 'https://my-cas-host.com/cas',
    service_url : 'https://my-service-host.com'
});
 
// Unauthenticated clients will be redirected to the CAS login and then back to 
// this route once authenticated. 
app.get( '/app', cas.bounce, function ( req, res ) {
    res.send( '<html><body>Hello!</body></html>' );
});
 
// Unauthenticated clients will receive a 401 Unauthorized response instead of 
// the JSON data. 
app.get( '/api', cas.block, function ( req, res ) {
    res.json( { success: true } );
});
 
// An example of accessing the CAS user session variable. This could be used to 
// retrieve your own local user records based on authenticated CAS username. 
app.get( '/api/user', cas.block, function ( req, res ) {
    res.json( { cas_user: req.session[ cas.session_name ] } );
});
 
// Unauthenticated clients will be redirected to the CAS login and then to the 
// provided "redirectTo" query parameter once authenticated. 
app.get( '/authenticate', cas.bounce_redirect );
 
// This route will de-authenticate the client with the Express server and then 
// redirect the client to the CAS logout page. 
app.get( '/logout', cas.logout );