Also available for PHP here.

This is a small class to help with providing an SSO source for Discourse forums. It provides 3 help functions for validating incoming requests, extracting nonce, and building the returning queryString.

For more information on the SSO settings in Discourse, visit https://meta.discourse.org/t/official-single-sign-on-for-discourse/13045

Simply install via npm, require the package and create a new object, providing the SSO secret defined in Discourse

var discourse_sso = require('discourse-sso');
var sso = new discourse_sso("-your-sso_secret-goes-here-");

To validate incoming logins, you can do:

var payload = ... // fetch from incoming request
var sig = ... // fetch from incoming request
if(sso.validate(payload, sig)) {
}

To extract the nonce(the little piece of data that identifies the login, read more in the above link), use:

var nonce = sso.getNonce(payload);

At last, to produce the query string that is to be sent back to discourse, do:

var userparams = {
	// Required, will throw exception otherwise
	"nonce": nonce,
	"external_id": "some user id here",
	"email": "some user email",
	// Optional
	"username": "some username",
	"name": "some real name"
};
var q = sso.buildLoginString(userparams);