feat: redirect handler

Signed-off-by: Wouter Termont <woutermont@gmail.com>

test/unit/server/RedirectingHttpHandler.test.ts

@@ -0,0 +1,56 @@
+import { EventEmitter } from 'events';
+import { createResponse } from 'node-mocks-http';
+import { RedirectingHttpHandler } from '../../../src/server/RedirectingHttpHandler';
+
+describe('A RedirectingHttpHandler', (): void => {
+  const handler = new RedirectingHttpHandler({
+    '/one': '/two',
+    '/from/(.*)': '/to/$1',
+    '/f([aeiou]+)/b([aeiou]+)r': '/f$2/b$1r',
+  });
+
+  afterEach(jest.clearAllMocks);
+
+  it('does not handle requests without URL.', async(): Promise<void> => {
+    const request = { method: 'GET' };
+    await expect(handler.canHandle({ request } as any)).rejects
+      .toThrow('No redirect configured for undefined');
+    await expect(handler.handle({ request } as any)).rejects
+      .toThrow('No redirect configured for undefined');
+  });
+
+  it('does not handle requests with unconfigured URLs.', async(): Promise<void> => {
+    const request = { method: 'GET', url: '/other' };
+    await expect(handler.canHandle({ request } as any)).rejects
+      .toThrow('No redirect configured for /other');
+    await expect(handler.handle({ request } as any)).rejects
+      .toThrow('No redirect configured for /other');
+  });
+
+  it('handles requests to a known URL.', async(): Promise<void> => {
+    const request = { method: 'GET', url: '/one' };
+    const response = createResponse({ eventEmitter: EventEmitter });
+    await handler.handleSafe({ request, response } as any);
+
+    expect(response.statusCode).toBe(308);
+    expect(response.getHeaders()).toHaveProperty('location', '/two');
+  });
+
+  it('handles correctly substitutes group patterns.', async(): Promise<void> => {
+    const request = { method: 'GET', url: '/fa/boor' };
+    const response = createResponse({ eventEmitter: EventEmitter });
+    await handler.handleSafe({ request, response } as any);
+
+    expect(response.getHeaders()).toHaveProperty('location', '/foo/bar');
+  });
+
+  it('redirects with the provided status code.', async(): Promise<void> => {
+    const seeOtherHandler = new RedirectingHttpHandler({ '/one': '/two' }, 303);
+    const request = { method: 'GET', url: '/one' };
+    const response = createResponse({ eventEmitter: EventEmitter });
+    await seeOtherHandler.handleSafe({ request, response } as any);
+
+    expect(response.statusCode).toBe(303);
+    expect(response.getHeaders()).toHaveProperty('location', '/two');
+  });
+});