Add API to be used with playground

README.md

@@ -519,6 +519,13 @@ Run `ng e2e` to execute the end-to-end tests via [Protractor](http://www.protrac
 
 The workspace includes a playground application that can be used to test out features of the SDK. Run this using `ng serve playground` and browse to http://localhost:4200.
 
+#### Running an express server
+
+An express server can be started by running `npm run server:api`, which can be used to make testing Http Interceptors easier.
+The express server exposes a single endpoint at `http://localhost:3001/api/external` that needs to be called with an `Authorization` header containing a token for the corresponding `domain` and `audience`, configurable in [`api-server.js`](api-server.js).
+
+The playground application is preconfigured to call the above endpoint when clicking the `Call external API` button.
+
 ## Further help
 
 To get more help on the Angular CLI use `ng help` or go check out the [Angular CLI README](https://github.com/angular/angular-cli/blob/master/README.md).

api-server.js

@@ -0,0 +1,45 @@
+const express = require('express');
+const cors = require('cors');
+const jwt = require('express-jwt');
+const jwksRsa = require('jwks-rsa');
+
+const app = express();
+
+const authConfig = {
+  domain: 'brucke.auth0.com',
+  audience: 'http://localhost/',
+  appUri: 'http://localhost:4200',
+};
+
+if (!authConfig.domain || !authConfig.audience) {
+  throw 'Please make sure that auth_config.json is in place and populated';
+}
+
+app.use(
+  cors({
+    origin: authConfig.appUri,
+  })
+);
+
+const checkJwt = jwt({
+  secret: jwksRsa.expressJwtSecret({
+    cache: true,
+    rateLimit: true,
+    jwksRequestsPerMinute: 5,
+    jwksUri: `https://${authConfig.domain}/.well-known/jwks.json`,
+  }),
+
+  audience: authConfig.audience,
+  issuer: `https://${authConfig.domain}/`,
+  algorithms: ['RS256'],
+});
+
+app.get('/api/external', checkJwt, (req, res) => {
+  res.send({
+    msg: 'Your access token was successfully validated!',
+  });
+});
+
+const port = process.env.API_SERVER_PORT || 3001;
+
+app.listen(port, () => console.log(`Api started on port ${port}`));