isabella232 / discourse-oauth2-basic

A basic OAuth2 plugin for use with Discourse

discourse-oauth2-basic

This plugin allows you to use a basic OAuth2 provider as authentication for Discourse. It should work with many providers, with the caveat that they must provide a JSON endpoint for retriving information about the user you are logging in.

This is mainly useful for people who are using login providers that aren't very popular. If you want to use Google, Facebook or Twitter, those are included out of the box and you don't need this plugin. You can also look for other login providers in our Github Repo.

Usage

Part 1: Basic Configuration

First, set up your Discourse application remotely on your OAuth2 provider. It will require a Redirect URI which should be:

http://DISCOURSE_HOST/auth/oauth2_basic/callback

Replace DISCOURSE_HOST with the approriate value, and make sure you are using https if enabled. The OAuth2 provider should supply you with a client ID and secret, as well as a couple of URLs.

Visit your Admin > Settings > Login and fill in the basic configuration for the OAuth2 provider:

• oauth2_enabled - check this off to enable the feature

• oauth2_client_id - the client ID from your provider

• oauth2_client_secret - the client secret from your provider

• oauth2_authorize_url - your provider's authorization URL

• oauth2_token_url - your provider's token URL.

If you can't figure out the values for the above settings, check the developer documentation from your provider or contact their customer support.

Part 2: Configuring the JSON User Endpoint

Discourse is now capable of receiving an authorization token from your OAuth2 provider. Unfortunately, Discourse requires more information to be able to complete the authentication.

We require an API endpoint that can be contacted to retrieve information about the user based on the token.

For example, the OAuth2 provider SoundCloud provides such a URL. If you have an OAuth2 token for SoundCloud, you can make a GET request to https://api.soundcloud.com/me?oauth_token=A_VALID_TOKEN and will get back a JSON object containing information on the user.

To configure this on Discourse, we need to set the value of the oauth2_user_json_url setting. In this case, we'll input the value of:

https://api.soundcloud.com/me?oauth_token=:token

The part with :token tells Discourse that it needs to replace that value with the authorization token it received when the authentication completed. Discourse will also add the Authorization: Bearer HTTP header with the token in case your API uses that instead.

There is one last step to complete. We need to tell Discourse what attributes are available in the JSON it received. Here's a sample response from SoundCloud:

{
  "id": 3207,
  "permalink": "jwagener",
  "username": "Johannes Wagener",
  "uri": "https://api.soundcloud.com/users/3207",
  "permalink_url": "http://soundcloud.com/jwagener",
  "avatar_url": "http://i1.sndcdn.com/avatars-000001552142-pbw8yd-large.jpg?142a848",
  "country": "Germany",
  "full_name": "Johannes Wagener",
  "city": "Berlin"
}

The oauth2_json_user_id_path, oauth2_json_username_path, oauth2_json_name_path and oauth2_json_email_path variables should be set to point to the appropriate attributes in the JSON.

The only mandatory attribute is id - we need that so when the user logs on in the future that we can pull up the correct account. The others are great if available -- they will make the signup process faster for the user as they will be pre-populated in the form.

Here's how I configured the JSON path settings:

  oauth2_json_user_id_path: 'id'
  oauth2_json_username_path: 'permalink'
  oauth2_json_name_path: 'full_name'

I used permalink because it seems more similar to what Discourse expects for a username than the username in their JSON. Notice I omitted the email path: SoundCloud do not provide an email so the user will have to provide and verify this when they sign up the first time on Discourse.

If the properties you want from your JSON object are nested, you can use periods. So for example if the API returned a different structure like this:

{
  "user": {
    "id": 1234,
    "email": {
      "address": "[email protected]"
    }
  }
}

You could use user.id for the oauth2_json_user_id_path and user.email.address for oauth2_json_email_path.

Part 3: Test it with Google OAuth 2.0 Server

To test this plugin in your local dev environment you can use Google OAuth 2.0 Server. Follow this guide to create new OAuth client id & secret.

• While creating it choose "Web application" as "Application type".
• Add http://localhost:3000 in "Authorized JavaScript origins" and http://localhost:3000/auth/oauth2_basic/callback in "Authorized redirect URIs" fields.
• Then add following site settings in your admin panel.

{
  "oauth2_enabled": true,
  "oauth2_client_id": "YOUR_PROJECT_CLIENT_ID",
  "oauth2_client_secret": "YOUR_PROJECT_CLIENT_SECRET",
  "oauth2_authorize_url": "https://accounts.google.com/o/oauth2/auth",
  "oauth2_token_url": "https://www.googleapis.com/oauth2/v3/token",
  "oauth2_user_json_url": "https://www.googleapis.com/userinfo/v2/me",
  "oauth2_json_user_id_path": "id",
  "oauth2_json_user_name_path": "name",
  "oauth2_json_user_email_path": "email",
  "oauth2_json_user_avatar_path": "picture",
  "oauth2_email_verified": true,
  "oauth2_scope": "https://www.googleapis.com/auth/userinfo.email"
}

That's it! You can check it now in your browser.

Good luck setting up custom OAuth2 on your Discourse!

Issues

Please use this topic on meta to discuss issues with the plugin, including bugs and feature reqests.

How to run tests

Make sure the plugin has been installed, then from the discourse directory run:

LOAD_PLUGINS=1 bundle exec rspec plugins/discourse-oauth2-basic/spec/plugin_spec.rb

License

MIT