app-backend: added static assets middleware + header constants

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
2021-12-29 16:52:59 +01:00
parent 3a7911ece8
commit 7261b76935
4 changed files with 186 additions and 0 deletions
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import express from 'express';
+import request from 'supertest';
+import { createStaticAssetsStoreMiddleware } from './createStaticAssetsStoreMiddleware';
+import { StaticAssetsStore } from './StaticAssetsStore';
+
+const mockStore = {
+  getAsset: jest.fn(),
+} as unknown as jest.Mocked<StaticAssetsStore>;
+
+describe('createStaticAssetsStoreMiddleware', () => {
+  const app = express();
+  app.use(createStaticAssetsStoreMiddleware(mockStore));
+  app.use((_req, res) => {
+    res.status(404).end('Not Found');
+  });
+
+  beforeEach(() => {
+    jest.resetAllMocks();
+  });
+
+  it('should respond with an asset', async () => {
+    const now = new Date();
+    mockStore.getAsset.mockResolvedValueOnce({
+      path: 'foo.js',
+      lastModifiedAt: now,
+      content: Buffer.from('foo'),
+    });
+
+    const res = await request(app).get('/foo.js');
+
+    expect(res.status).toBe(200);
+    expect(res.text).toBe('foo');
+    expect(res.get('Content-Type')).toBe(
+      'application/javascript; charset=utf-8',
+    );
+    expect(res.get('Content-Length')).toBe('3');
+    expect(res.get('Cache-Control')).toBe('public, max-age=1209600');
+    expect(res.get('Last-Modified')).toBe(now.toUTCString());
+
+    expect(mockStore.getAsset).toHaveBeenCalledTimes(1);
+    expect(mockStore.getAsset).toHaveBeenCalledWith('foo.js');
+  });
+
+  mockStore.getAsset.mockResolvedValueOnce(undefined);
+
+  it('should respond with not found', async () => {
+    const res = await request(app).get('/foo.js');
+
+    expect(res.status).toBe(404);
+    expect(res.text).toBe('Not Found');
+
+    expect(mockStore.getAsset).toHaveBeenCalledTimes(1);
+    expect(mockStore.getAsset).toHaveBeenCalledWith('foo.js');
+  });
+
+  it('should handle other content type', async () => {
+    mockStore.getAsset.mockResolvedValueOnce({
+      path: 'foo.css',
+      lastModifiedAt: new Date(),
+      content: Buffer.from('foo'),
+    });
+
+    const res = await request(app).get('/foo.css');
+
+    expect(res.status).toBe(200);
+    expect(res.text).toBe('foo');
+    expect(res.get('Content-Type')).toBe('text/css; charset=utf-8');
+    expect(res.get('Content-Length')).toBe('3');
+
+    expect(mockStore.getAsset).toHaveBeenCalledTimes(1);
+    expect(mockStore.getAsset).toHaveBeenLastCalledWith('foo.css');
+  });
+
+  it('should handle unknown content types', async () => {
+    mockStore.getAsset.mockResolvedValueOnce({
+      path: 'foo.notavalidextension',
+      lastModifiedAt: new Date(),
+      content: Buffer.from('foo'),
+    });
+
+    const res = await request(app).get('/foo.notavalidextension');
+
+    expect(res.status).toBe(200);
+    expect(res.body).toEqual(Buffer.from('foo'));
+    expect(res.get('Content-Type')).toBe('application/octet-stream');
+    expect(res.get('Content-Length')).toBe('3');
+
+    expect(mockStore.getAsset).toHaveBeenCalledTimes(1);
+    expect(mockStore.getAsset).toHaveBeenLastCalledWith(
+      'foo.notavalidextension',
+    );
+  });
+});
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { extname } from 'path';
+import { RequestHandler } from 'express';
+import { StaticAssetsStore } from './StaticAssetsStore';
+import { CACHE_CONTROL_MAX_CACHE } from '../headers';
+
+export function createStaticAssetsStoreMiddleware(
+  store: StaticAssetsStore,
+): RequestHandler {
+  return (req, res, next) => {
+    if (req.method !== 'GET' && req.method !== 'HEAD') {
+      next();
+      return;
+    }
+
+    Promise.resolve(
+      (async () => {
+        // Drop leading slashes from the incoming path
+        const path = req.path.startsWith('/') ? req.path.slice(1) : req.path;
+
+        const asset = await store.getAsset(path);
+        if (!asset) {
+          next();
+          return;
+        }
+
+        // Set the Content-Type header, falling back to octet-stream
+        const ext = extname(asset.path);
+        if (ext) {
+          res.type(ext);
+        } else {
+          res.type('bin');
+        }
+
+        // Same as our express.static override
+        res.setHeader('Cache-Control', CACHE_CONTROL_MAX_CACHE);
+        res.setHeader('Last-Modified', asset.lastModifiedAt.toUTCString());
+
+        res.send(asset.content);
+      })(),
+    ).catch(next);
+  };
+}
@@ -17,3 +17,4 @@
 export { StaticAssetsStore } from './StaticAssetsStore';
 export type { StaticAsset, StaticAssetInput } from './types';
 export { findStaticAssets } from './findStaticAssets';
+export { createStaticAssetsStoreMiddleware } from './createStaticAssetsStoreMiddleware';
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export const CACHE_CONTROL_NO_CACHE = 'no-store, max-age=0';
+export const CACHE_CONTROL_MAX_CACHE = 'public, max-age=1209600'; // 14 days