fix(rest-explorer): allow explorer for a rest app to be mounted to ex…

…press

This is a follow-up to #2387

packages/rest-explorer/package.json

@@ -28,7 +28,9 @@
     "@loopback/testlab": "^1.0.7",
     "@loopback/tslint-config": "^2.0.1",
     "@types/ejs": "^2.6.0",
-    "@types/node": "^10.1.1"
+    "@types/express": "^4.16.1",
+    "@types/node": "^10.1.1",
+    "express": "^4.16.4"
   },
   "keywords": [
     "LoopBack",

packages/rest-explorer/src/__tests__/acceptance/rest-explorer.express.acceptance.ts

@@ -0,0 +1,65 @@
+// Copyright IBM Corp. 2017,2018. All Rights Reserved.
+// Node module: @loopback/rest
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {
+  HttpRequestListener,
+  RestApplication,
+  RestServer,
+  RestServerConfig,
+} from '@loopback/rest';
+import {
+  Client,
+  createClientForHandler,
+  givenHttpServerConfig,
+} from '@loopback/testlab';
+import * as express from 'express';
+import {RestExplorerComponent} from '../..';
+
+describe('REST Explorer mounted as an express router', () => {
+  let client: Client;
+  let expressApp: express.Application;
+  let server: RestServer;
+  let handler: HttpRequestListener;
+  beforeEach(givenLoopBackApp);
+  beforeEach(givenExpressApp);
+  beforeEach(givenClient);
+
+  it('exposes API Explorer at "/api/explorer/"', async () => {
+    await client
+      .get('/api/explorer/')
+      .expect(200)
+      .expect('content-type', /html/)
+      .expect(/url\: '\/api\/openapi\.json'\,/);
+  });
+
+  it('redirects from "/api/explorer" to "/api/explorer/"', async () => {
+    await client
+      .get('/api/explorer')
+      .expect(301)
+      .expect('location', '/api/explorer/');
+  });
+
+  async function givenLoopBackApp(
+    options: {rest: RestServerConfig} = {rest: {port: 0}},
+  ) {
+    options.rest = givenHttpServerConfig(options.rest);
+    const app = new RestApplication(options);
+    app.component(RestExplorerComponent);
+    server = await app.getServer(RestServer);
+    handler = server.requestHandler;
+  }
+
+  /**
+   * Create an express app that mounts the LoopBack routes to `/api`
+   */
+  function givenExpressApp() {
+    expressApp = express();
+    expressApp.use('/api', handler);
+  }
+
+  function givenClient() {
+    client = createClientForHandler(expressApp);
+  }
+});

packages/rest-explorer/src/rest-explorer.controller.ts

@@ -33,12 +33,20 @@ export class ExplorerController {
   }
 
   indexRedirect() {
-    this.response.redirect(301, this.request.url + '/');
+    let url = this.request.url + '/';
+    if (this.request.baseUrl && this.request.baseUrl !== '/') {
+      url = this.request.baseUrl + url;
+    }
+    this.response.redirect(301, url);
   }
 
   index() {
+    let openApiSpecUrl = this.openApiSpecUrl;
+    if (this.request.baseUrl && this.request.baseUrl !== '/') {
+      openApiSpecUrl = this.request.baseUrl + openApiSpecUrl;
+    }
     const data = {
-      openApiSpecUrl: this.openApiSpecUrl,
+      openApiSpecUrl,
     };
 
     const homePage = templateFn(data);