cas

Central Authentication Service (CAS) client for Node.js

This module handles CAS authentication (with support for proxies and extended attributes), and can also transparently redirect a web page if needed. The ticket validation step is available as its own function for those who wish to handle things manually. Single sign out is also supported with Express/Connect.

To start the login process manually, send your users to: https://cas_base_url/login?service=url_to_handle_ticket_validation. In the University of Waterloo example below, this url would be: https://cas.uwaterloo.ca/cas/login?service='my_service'.

Or if you are using standard HTTP req/res objects for a web page, you may use the provided authenticate() function to handle the redirection automatically.

It is also possible to use this as a standalone CAS PGT callback server that other CAS clients can use.

Installation

Clone this project into node_modules/cas and then run npm install inside it.

Usage

Setup:

    var CAS = require('cas');
    var cas = new CAS({
        base_url: 'https://cas.uwaterloo.ca/cas', 
        service: 'my_service',
        version: 2.0
    });

Using it in a login route:

    exports.cas_login = function(req, res) {
      var ticket = req.param('ticket');
      if (ticket) {
        cas.validate(ticket, function(err, status, username) {
          if (err) {
            // Handle the error
            res.send({error: err});
          } else {
            // Log the user in
            res.send({status: status, username: username});
          }
        });
      } else {
        res.redirect('/');
      }
    };

Using the auto redirect authentication:

    exports.cas_login = function(req, res) {
      cas.authenticate(req, res, function(err, status, username, extended) {
        if (err) {
          // Handle the error
          res.send({error: err});
        } else {
          // Log the user in 
          res.send({status: status, username: username, attributes: extended.attributes});
        }
      });    
    }

Longer example with CAS proxy (also see the wiki):

    var fs = require('fs');
    var http = require('http');

    // Initialize CAS
    var CAS = require('cas');
    var cas = new CAS({
        base_url: 'https://cas.uwaterloo.ca/cas',
        version: 2.0,
        
        // CAS server will connect to this. It must be accessible on the
        // public internet.
        pgt_server: true,
        ssl_key: fs.readFileSync('/path/to/private_key.pem'),
        ssl_cert: fs.readFileSync('/path/to/ssl_cert.pem'),
        pgt_host: 'my-public-domain.example.com',
        pgt_port: 8989
    });
    
    // Main web server
    var server = http.createServer();
    server.addListener('request', function(req, res) {

        var ip = req.connection.remoteAddress
             || req.socket.remoteAddress 
             || req.connection.socket.remoteAddress;
        
        cas.authenticate(req, res, function(err, status, username, extended) {
            if (err) {
                res.end(err.message);
                return;
            }
            
            // At this point the user has been authenticated. In a real web
            // framework you would want to use sessions to track the info.
            
            res.writeHead(200, {'Content-Type': 'text/html'});
            res.write('<div style="border:solid 1px black; padding:1em; margin:1em;">');
            res.write('<p>Welcome ' + username + '. Your IP address is ' + ip + '.</p>');
            res.write('<p>You are here: <b>http://' + req.headers.host + req.url + '</b></p>');
            
            // CAS server should return a PGTIOU since we specified a PGT callback
            var pgtIOU = extended['PGTIOU'];
            if (pgtIOU) {
                res.write('<p>');
                res.write('Your PGTIOU for this session is: ' + pgtIOU + '<br/>');
                res.write('Your web framework should keep track of this if it wants to use CAS proxied services on your behalf.<br/>');
                res.write('</p>');
                
                // Now you are authorized to fetch a 3rd party service on behalf
                // of the user.
                var url = "http://example.com/user/info";
                cas.getProxyTicket(pgtIOU, url, function(err, ticket) {
                    if (!err) {
                        url += '?ticket=' + ticket;
                        request(url, ... )
                    }
                    res.write('</div>');
                    res.end();
                });
            }
            
            else {
                res.write('</div>');
                res.end();
            }
        
        });
        
    });
    server.listen(8080);

License

(The MIT License)

Copyright (c) 2011 Casey Banner <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.