Discriminator validation issue

examples/validation-app/src/__tests__/acceptance/validate-discriminator.acceptance.ts

@@ -0,0 +1,89 @@
+// Copyright IBM Corp. and LoopBack contributors 2020. All Rights Reserved.
+// Node module: @loopback/example-validation-app
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {Client, expect} from '@loopback/testlab';
+import {ValidationApplication} from '../..';
+import {setupApplication} from './test-helper';
+
+const validCat = {
+  name: 'Kitty',
+  weight: 5,
+  kind: 'Cat',
+  animalProperties: {
+    color: 'grey',
+    whiskerLength: 2,
+  },
+};
+
+const validDog = {
+  name: 'Rex',
+  weight: 5,
+  kind: 'Dog',
+  animalProperties: {
+    breed: 'poodle',
+    barkVolume: 5,
+  },
+};
+
+describe('validate properties based on discriminated schemas', () => {
+  let client: Client;
+  let app: ValidationApplication;
+
+  before(givenAClient);
+
+  after(async () => {
+    await app.stop();
+  });
+
+  async function givenAClient() {
+    ({app, client} = await setupApplication());
+  }
+
+  it('should pass with valid cat properties', async () => {
+    await client.post('/pets').send(validCat).expect(200);
+  });
+
+  it('should pass with valid dog properties', async () => {
+    await client.post('/pets').send(validDog).expect(200);
+  });
+
+  it('should fail with error indicating invalid barkVolume type', async () => {
+    const invalidDog = {...validDog};
+    invalidDog.animalProperties.barkVolume = 'loud' as unknown as number;
+    const response = await client.post('/pets').send(invalidDog).expect(422);
+
+    expect(response.body.error.details.length).to.equal(1);
+    expect(response.body.error.details[0].message).to.equal('must be number');
+    expect(response.body.error.details).to.deepEqual([
+      {
+        code: 'type',
+        info: {
+          type: 'number',
+        },
+        message: 'must be number',
+        path: '/animalProperties/barkVolume',
+      },
+    ]);
+  });
+
+  it('should fail with error indicating invalid whiskerLength type', async () => {
+    const invalidCat = {...validCat};
+    invalidCat.animalProperties.whiskerLength = 'long' as unknown as number;
+    const response = await client.post('/pets').send(invalidCat).expect(422);
+
+    expect(response.body.error.details.length).to.equal(1);
+    expect(response.body.error.details[0].message).to.equal('must be number');
+    expect(response.body.error.details).to.deepEqual([
+      {
+        code: 'type',
+        info: {
+          type: 'number',
+        },
+        message: 'must be number',
+        path: '/animalProperties/whiskerLength',
+      },
+    ]);
+  });
+});

examples/validation-app/src/application.ts

@@ -6,7 +6,7 @@
 import {BootMixin} from '@loopback/boot';
 import {ApplicationConfig, createBindingFromClass} from '@loopback/core';
 import {RepositoryMixin} from '@loopback/repository';
-import {RestApplication} from '@loopback/rest';
+import {RestApplication, RestBindings} from '@loopback/rest';
 import {
   RestExplorerBindings,
   RestExplorerComponent,
@@ -32,6 +32,12 @@ export class ValidationApplication extends BootMixin(
     // Set up default home page
     this.static('/', path.join(__dirname, '../public'));
 
+    this.bind(RestBindings.REQUEST_BODY_PARSER_OPTIONS).to({
+      validation: {
+        discriminator: true,
+      },
+    });
+
     // Customize @loopback/rest-explorer configuration here
     this.configure(RestExplorerBindings.COMPONENT).to({
       path: '/explorer',

examples/validation-app/src/controllers/index.ts

@@ -4,3 +4,4 @@
 // License text available at https://opensource.org/licenses/MIT
 
 export * from './coffee-shop.controller';
+export * from './pet.controller';

examples/validation-app/src/controllers/pet.controller.ts

@@ -0,0 +1,30 @@
+// Copyright IBM Corp. and LoopBack contributors 2020. All Rights Reserved.
+// Node module: @loopback/example-validation-app
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {post, requestBody} from '@loopback/rest';
+import {Cat, Dog, Pet} from '../models';
+
+export class PetController {
+  constructor() {}
+
+  @post('/pets')
+  async create(
+    @requestBody({
+      content: {
+        'application/json': {
+          schema: {
+            discriminator: {
+              propertyName: 'kind',
+            },
+            oneOf: [{'x-ts-type': Cat}, {'x-ts-type': Dog}],
+          },
+        },
+      },
+    })
+    request: Pet,
+  ): Promise<Pet> {
+    return request;
+  }
+}

examples/validation-app/src/middleware/validation-error.middleware.ts

@@ -54,7 +54,10 @@ export class ValidationErrorMiddlewareProvider implements Provider<Middleware> {
     err: HttpErrors.HttpError,
   ): Response | undefined {
     // 2. customize error for particular endpoint
-    if (context.request.url === '/coffee-shops') {
+    if (
+      context.request.url === '/coffee-shops' ||
+      context.request.url === '/pets'
+    ) {
       // if this is a validation error from the PATCH method, customize it
       // for other validation errors, the default AJV error object will be sent
       if (err.statusCode === 422 && context.request.method === 'PATCH') {

examples/validation-app/src/models/index.ts

@@ -4,3 +4,4 @@
 // License text available at https://opensource.org/licenses/MIT
 
 export * from './coffee-shop.model';
+export * from './pet.model';

examples/validation-app/src/models/pet.model.ts

@@ -0,0 +1,86 @@
+import {Model, model, property} from '@loopback/repository';
+
+@model()
+export class CatProperties extends Model {
+  @property({
+    type: String,
+    required: true,
+  })
+  color: string;
+
+  @property({
+    type: Number,
+    required: true,
+  })
+  whiskerLength: number;
+}
+
+@model()
+export class DogProperties extends Model {
+  @property({
+    type: String,
+    required: true,
+  })
+  breed: string;
+
+  @property({
+    type: Number,
+    required: true,
+  })
+  barkVolume: number;
+}
+
+@model()
+export class Pet extends Model {
+  @property({
+    type: String,
+    required: true,
+  })
+  name: string;
+
+  @property({
+    type: Number,
+    required: false,
+  })
+  weight?: number;
+
+  kind: string;
+
+  animalProperties: CatProperties | DogProperties;
+}
+
+@model()
+export class Dog extends Pet {
+  @property({
+    type: String,
+    jsonSchema: {
+      enum: ['Dog'],
+    },
+    required: true,
+  })
+  kind: string;
+
+  @property({
+    type: DogProperties,
+    required: true,
+  })
+  animalProperties: DogProperties;
+}
+
+@model()
+export class Cat extends Pet {
+  @property({
+    type: String,
+    jsonSchema: {
+      enum: ['Cat'],
+    },
+    required: true,
+  })
+  kind: string;
+
+  @property({
+    type: CatProperties,
+    required: true,
+  })
+  animalProperties: CatProperties;
+}

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

@@ -84,7 +84,10 @@ export async function validateRequestBody(
  * @param openapiSchema - The OpenAPI schema to convert.
  */
 function convertToJsonSchema(openapiSchema: SchemaObject) {
-  const jsonSchema = toJsonSchema(openapiSchema);
+  const jsonSchema = toJsonSchema(openapiSchema, {
+    keepNotSupported: ['discriminator'],
+  });
+
   delete jsonSchema['$schema'];
   /* istanbul ignore if */
   if (debug.enabled) {