Strict mode: unknown keyword: "discriminator"

[manchuwook]

Hi All,
I've mostly using the same schema for the past few months - but I have applied the update for Loopback and now I'm getting grief about the discriminators. OpenAPI generator tells me I need to have them in order to do inheritance, but I'm confused as to why now LB is confused with it. Is there some setting that I need to switch off and will it cause problems with other stuff?

Request POST /v1/characters failed with status code 500. Error: strict mode: unknown keyword: "discriminator"
    at checkStrictMode (S:\dev\site\project\node_modules\ajv\lib\compile\util.ts:211:28)
    at Object.checkUnknownRules (S:\dev\site\project\node_modules\ajv\lib\compile\util.ts:27:22)
    at checkKeywords (S:\dev\site\project\node_modules\ajv\lib\compile\validate\index.ts:153:3)
    at Object.validateFunctionCode (S:\dev\site\project\node_modules\ajv\lib\compile\validate\index.ts:40:5)
    at Ajv.compileSchema (S:\dev\site\project\node_modules\ajv\lib\compile\index.ts:163:5)
    at Ajv.inlineOrCompile (S:\dev\site\project\node_modules\ajv\lib\compile\index.ts:228:45)
    at Ajv.resolveRef (S:\dev\site\project\node_modules\ajv\lib\compile\index.ts:223:44)
    at Object.code (S:\dev\site\project\node_modules\ajv\lib\vocabularies\core\ref.ts:18:33)
    at keywordCode (S:\dev\site\project\node_modules\ajv\lib\compile\validate\index.ts:523:9)
    at S:\dev\site\project\node_modules\ajv\lib\compile\validate\index.ts:228:21
    at CodeGen.code (S:\dev\site\project\node_modules\ajv\lib\compile\codegen\index.ts:525:33)
    at CodeGen.block (S:\dev\site\project\node_modules\ajv\lib\compile\codegen\index.ts:680:20)
    at schemaKeywords (S:\dev\site\project\node_modules\ajv\lib\compile\validate\index.ts:228:9)
    at typeAndKeywords (S:\dev\site\project\node_modules\ajv\lib\compile\validate\index.ts:161:3)
    at S:\dev\site\project\node_modules\ajv\lib\compile\validate\index.ts:100:5
    at CodeGen.code (S:\dev\site\project\node_modules\ajv\lib\compile\codegen\index.ts:525:33)

[raymondfeng]

It's related to AJV 8.x upgrade. See https://ajv.js.org/strict-mode.html#unknown-keywords.

[manchuwook]

Is this something I can do at the application level? A la .env's require('dotenv').config() ?

[raymondfeng]

https://loopback.io/doc/en/lb4/Extending-request-body-parsing.html#customize-parser-options

[manchuwook]

Well, I added it to index.ts

import { RestBindings } from '@loopback/rest';
import { ApplicationConfig, PlayerApiApplication } from './application';
import { MyJsonBodyParser } from './body-parsers';

export * from './application';
export * from './types';

export async function main(options: ApplicationConfig = {}) {
  const app = new PlayerApiApplication(options);

  app.bodyParser(MyJsonBodyParser, RestBindings.REQUEST_BODY_PARSER_JSON);

  await app.boot();
  await app.start();
 /** ... */
}

And then for the body parser

import { inject } from '@loopback/core';
import {
  BodyParser,
  BodyParserMiddleware,
  builtinParsers,
  getParserOptions,
  invokeBodyParserMiddleware,
  RequestBody,
  RequestBodyParserOptions,
  RestBindings,
  sanitizeJsonParse
} from '@loopback/rest';
import { json } from 'express';
import { is } from 'type-is';

export class MyJsonBodyParser implements BodyParser {
  name = builtinParsers.json;
  private jsonParser: BodyParserMiddleware;

  constructor(
    @inject(RestBindings.REQUEST_BODY_PARSER_OPTIONS, { optional: true })
    options: RequestBodyParserOptions = {},
  ) {
    // Unset strict
    options.json.strict = false;
  /** ... */
}

To which, it does nothing.

Request POST /v1/characters failed with status code 500. Error: strict mode: unknown keyword: "discriminator"

[manchuwook]

I figured it out

index.ts

  app.bind(RestBindings.REQUEST_BODY_PARSER_OPTIONS).to({
    limit: '1MB',
    json: {
      strict: false
    },
    text: {
      limit: '2MB'
    },
    /**
     * Validation options for AJV, see https://github.com/epoberezkin/ajv#options
     * This setting is global for all request body parsers and it cannot be
     * overridden inside parser specific properties such as `json` or `text`.
     */
    validation: {
      strict: false
    },
  });