asl-service

Module for rapid bootstrapping of an express app for a govuk themed, react-based ui or api with logging, authentication and session handling configured as appropriate.

Usage

UI

1const ui = require('asl-service/ui');
2const app = ui(settings);
3
4app.use(/* mount your middleware and routes here */);
5
6app.listen(port);

Static middleware

If you wish to mount middleware before the session and auth handlers in a UI app you can do so with app.static.use which will mount your handlers before any dynamic middlewares are mounted.

This is primarily expected to be used for css, js or iamge assets.

API

1const api = require('asl-service/api');
2const app = api(settings);
3
4app.use(/* mount your middleware and routes here */);
5
6app.listen(port);

Settings

An example settings object looks like this:

1{
2  auth: {
3    // all apps
4  },
5  session: {
6    // ui only
7  }
8}

auth

Both UI and API applications will mount keycloak authentication middlewares. This requires the following properties to be set:

• realm
• url
• client
• secret

The values for these can be found in the Installation tab of your client's settings in the keycloak admin console. Select the Keycloak OIDC JSON option.

Once the auth middleware has been mounted, subsequent requests will have a req.user property with basic information about the logged in user.

User roles

You can limit access to routes to particular user roles by either checking the user's role directly with req.user.is('role') or by protecting the routes with app.protect('role').

Examples:

1const api = require('asl-service/api');
2const app = api(settings);
3
4app.protect('administrator');
5app.use(/* only users with the `administrator` role will be able to access routes mounted here */);
6
7app.listen(port);

1app.use((req, res, next) => {
2  if (!req.user.is('administrator')) {
3    return next(new Error('Access denied'));
4  }
5});

session

UI applications also require session storage configuration to be set.

• secret
• host - redis host
• port - redis port
• password - redis password if required

Other session configuration settings are documented here.

Other settings

UI applications can also use the following settings:

• assets - defines a folder that will be served as static assets - default: ./public
• views - defines the location of the application's views - default ./views