NodeJS HTTPS daemon example showing how to access client certificate information.

https-server.js

var https = require('https');
var sys   = require('util');
var fs    = require('fs');

/* Generate certs using OpenSSL as follows:
   openssl genrsa -des3 -passout pass:x -out server.pass.key 2048
   openssl rsa -passin pass:x -in server.pass.key -out server.key
   rm server.pass.key
 
   openssl req -new -key server.key -out server.csr -batch
   openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt
   rm server.csr
*/

var options = {
    key: fs.readFileSync('server.key'),
    cert: fs.readFileSync('server.crt'),
    requestCert:        true,
    //ca: [ fs.readFileSync('server.crt') ],
};

var server = https.createServer(options, function (req, res) {
    res.writeHead(200);

    // Can only be true if there is a CA cert defined in options and the client
    // cert is signed by it + valid
    sys.puts(req.client.authorized);

    // FIXME: no way to get the actual cert (does that make sense?)
    var clientCert = req.connection.getPeerCertificate();
    if (clientCert) {
        sys.puts(sys.inspect(clientCert));
        //sys.puts(JSON.stringify(clientCert.subject));
        //sys.puts(JSON.stringify(clientCert.fingerprint));
        //sys.puts(sys.inspect(req.connection.getCipher()));

    }
    else {
        sys.puts("Client not using a cert\n");
    }

    res.end("Hello world\n");
});
server.on('error', function (e) {
    sys.puts(e.message);
});
server.listen(8443);