feat: validate API requests and responses according to the OpenApi spec

Signed-off-by: Philippe Martin <phmartin@redhat.com>

Author: feloy

Diff for: packages/backend/package.json

@@ -71,6 +71,7 @@
   "dependencies": {
     "@huggingface/gguf": "^0.1.9",
     "express": "^4.19.2",
+    "express-openapi-validator": "^5.3.1",
     "isomorphic-git": "^1.27.1",
     "mustache": "^4.2.0",
     "openai": "^4.56.0",

Diff for: packages/backend/src/managers/apiServer.spec.ts

@@ -114,9 +114,16 @@ test('/api/version endpoint when getting package.json file fails', async () => {
   expect(res.body.errors[0]).toEqual('an error getting package file');
 });
 
+test('/api/version endpoint with unexpected param', async () => {
+  expect(server.getListener()).toBeDefined();
+  const res = await request(server.getListener()!).get('/api/version?wrongParam').expect(400);
+  expect(res.body.message).toEqual(`Unknown query parameter 'wrongParam'`);
+});
+
 test('/api/wrongEndpoint', async () => {
   expect(server.getListener()).toBeDefined();
-  await request(server.getListener()!).get('/api/wrongEndpoint').expect(404);
+  const res = await request(server.getListener()!).get('/api/wrongEndpoint').expect(404);
+  expect(res.body.message).toEqual('not found');
 });
 
 test('/', async () => {

Diff for: packages/backend/src/managers/apiServer.ts

@@ -17,7 +17,7 @@
  ***********************************************************************/
 
 import type { Disposable } from '@podman-desktop/api';
-import type { Request, Response } from 'express';
+import type { NextFunction, Request, Response } from 'express';
 import express from 'express';
 import type { Server } from 'http';
 import path from 'node:path';
@@ -30,6 +30,8 @@ import type { components } from '../../src-generated/openapi';
 import type { ModelInfo } from '@shared/src/models/IModelInfo';
 import type { ConfigurationRegistry } from '../registries/ConfigurationRegistry';
 import { getFreeRandomPort } from '../utils/ports';
+import * as OpenApiValidator from 'express-openapi-validator';
+import type { HttpError, OpenApiRequest } from 'express-openapi-validator/dist/framework/types';
 
 const SHOW_API_INFO_COMMAND = 'ai-lab.show-api-info';
 const SHOW_API_ERROR_COMMAND = 'ai-lab.show-api-error';
@@ -68,6 +70,29 @@ export class ApiServer implements Disposable {
     const router = express.Router();
     router.use(express.json());
 
+    // validate requests / responses based on openapi spec
+    router.use(
+      OpenApiValidator.middleware({
+        apiSpec: this.getSpecFile(),
+        validateRequests: true,
+        validateResponses: {
+          onError: (error, body, req) => {
+            console.error(`Response body fails validation: `, error);
+            console.error(`Emitted from:`, req.originalUrl);
+            console.error(body);
+          },
+        },
+      }),
+    );
+
+    router.use((err: HttpError, _req: OpenApiRequest, res: Response, _next: NextFunction) => {
+      // format errors from validator
+      res.status(err.status || 500).json({
+        message: err.message,
+        errors: err.errors,
+      });
+    });
+
     // declare routes
     router.get('/version', this.getVersion.bind(this));
     router.get('/tags', this.getModels.bind(this));

Diff for: packages/backend/vite.config.js

@@ -34,6 +34,8 @@ const config = {
       '/@/': join(PACKAGE_ROOT, 'src') + '/',
       '/@gen/': join(PACKAGE_ROOT, 'src-generated') + '/',
       '@shared/': join(PACKAGE_ROOT, '../shared') + '/',
+      '@jsdevtools/ono': '@jsdevtools/ono/cjs/index.js',
+      'ono': '@jsdevtools/ono/cjs/index.js',
     },
     mainFields: ['module', 'jsnext:main', 'jsnext'], //https://github.com/vitejs/vite/issues/16444
   },