feat(rest): add support for ajv-keywords

packages/rest/package.json

@@ -32,6 +32,7 @@
     "@types/serve-static": "1.13.2",
     "@types/type-is": "^1.6.2",
     "ajv": "^6.10.2",
+    "ajv-keywords": "^3.4.1",
     "body-parser": "^1.19.0",
     "cors": "^2.8.5",
     "debug": "^4.1.1",

packages/rest/src/__tests__/acceptance/validation/validation.acceptance.ts

@@ -38,7 +38,7 @@ describe('Validation at REST level', () => {
     @property({required: false, type: 'string', jsonSchema: {nullable: true}})
     description?: string | null;
 
-    @property({required: true})
+    @property({required: true, jsonSchema: {range: [0, 100]}})
     price: number;
 
     constructor(data: Partial<Product>) {
@@ -115,6 +115,7 @@ describe('Validation at REST level', () => {
       givenAnAppAndAClient(ProductController, {
         nullable: false,
         compiledSchemaCache: new WeakMap(),
+        ajvKeywords: ['range'],
       }),
     );
     after(() => app.stop());
@@ -150,6 +151,99 @@ describe('Validation at REST level', () => {
         },
       });
     });
+
+    it('rejects requests with price out of range', async () => {
+      const DATA = {
+        name: 'iPhone',
+        description: 'iPhone',
+        price: 200,
+      };
+      const res = await client
+        .post('/products')
+        .send(DATA)
+        .expect(422);
+
+      expect(res.body).to.eql({
+        error: {
+          statusCode: 422,
+          name: 'UnprocessableEntityError',
+          message:
+            'The request body is invalid. See error object `details` property for more info.',
+          code: 'VALIDATION_FAILED',
+          details: [
+            {
+              path: '.price',
+              code: 'maximum',
+              message: 'should be <= 100',
+              info: {comparison: '<=', limit: 100, exclusive: false},
+            },
+            {
+              path: '.price',
+              code: 'range',
+              message: 'should pass "range" keyword validation',
+              info: {keyword: 'range'},
+            },
+          ],
+        },
+      });
+    });
+  });
+
+  context('with request body validation options - {ajvKeywords: true}', () => {
+    class ProductController {
+      @post('/products')
+      async create(
+        @requestBody({required: true}) data: Product,
+      ): Promise<Product> {
+        return new Product(data);
+      }
+    }
+
+    before(() =>
+      givenAnAppAndAClient(ProductController, {
+        nullable: false,
+        compiledSchemaCache: new WeakMap(),
+        $data: true,
+        ajvKeywords: true,
+      }),
+    );
+    after(() => app.stop());
+
+    it('rejects requests with price out of range', async () => {
+      const DATA = {
+        name: 'iPhone',
+        description: 'iPhone',
+        price: 200,
+      };
+      const res = await client
+        .post('/products')
+        .send(DATA)
+        .expect(422);
+
+      expect(res.body).to.eql({
+        error: {
+          statusCode: 422,
+          name: 'UnprocessableEntityError',
+          message:
+            'The request body is invalid. See error object `details` property for more info.',
+          code: 'VALIDATION_FAILED',
+          details: [
+            {
+              path: '.price',
+              code: 'maximum',
+              message: 'should be <= 100',
+              info: {comparison: '<=', limit: 100, exclusive: false},
+            },
+            {
+              path: '.price',
+              code: 'range',
+              message: 'should pass "range" keyword validation',
+              info: {keyword: 'range'},
+            },
+          ],
+        },
+      });
+    });
   });
 
   // A request body schema can be provided explicitly by the user

packages/rest/src/types.ts

@@ -101,6 +101,12 @@ export interface RequestBodyValidationOptions extends ajv.Options {
    * to skip the default cache.
    */
   compiledSchemaCache?: SchemaValidatorCache;
+  /**
+   * Enable additional AJV keywords from https://github.com/epoberezkin/ajv-keywords
+   * - `true`: Add all keywords from `ajv-keywords`
+   * - `string[]`: Add an array of keywords from `ajv-keywords`
+   */
+  ajvKeywords?: true | string[];
 }
 
 /* eslint-disable @typescript-eslint/no-explicit-any */

packages/rest/src/validation/request-body.validator.ts

@@ -19,6 +19,8 @@ import {RequestBodyValidationOptions, SchemaValidatorCache} from '../types';
 const toJsonSchema = require('openapi-schema-to-json-schema');
 const debug = debugModule('loopback:rest:validation');
 
+const ajvKeywords = require('ajv-keywords');
+
 /**
  * Check whether the request body is valid according to the provided OpenAPI schema.
  * The JSON schema is generated from the OpenAPI schema which is typically defined
@@ -183,5 +185,11 @@ function createValidator(
   debug('AJV options', options);
   const ajv = new AJV(options);
 
+  if (options.ajvKeywords === true) {
+    ajvKeywords(ajv);
+  } else if (Array.isArray(options.ajvKeywords)) {
+    ajvKeywords(ajv, options.ajvKeywords);
+  }
+
   return ajv.compile(schemaWithRef);
 }