Using @kbn/config-schema to validate Legacy Platform routes

route.ts

import { schema } from '@kbn/config-schema';

function defineMyRoute(server) {

  const routeValidationSchema = schema.object({
    foo: schema.string(),
    bar: schema.maybe(schema.number({ min: 2, max: 200 })),
    baz: schema.boolean()
  });

  server.route({
    method: 'POST',
    path: '/api/my_app/my_app_route',
    options: {
      validate: {
        payload: function(payloadBody) {
          return routeValidationSchema.validate(payloadBody);
        }
      }
    },
    handler(request, response) {
      doSomeWork(request);
    }
  });
}

Example output for failed request:

elastic-mbp:8.0.0 larry$ curl https://localhost:5601/foo/api/security/v1/me -u elastic:changeme -X POST -H kbn-xsrf:true -H content-type:application/json -d'{"foo": 12}'

{"statusCode":400,"error":"Bad Request","message":"[foo]: expected value of type [string] but got [number]","validation":{"source":"payload","keys":[]}}