Schema Validator Component (@dcl/schema-validator-component)

A component that exposes a middleware to be used to validate JSON schemas in HTTP bodies.

Features

• Validation of AJV schemas.

Usage

import { createSchemaValidatorComponent } from '@dcl/schema-validator-component'

const schema = {
  type: 'object',
  properties: {
    aTestProp: {
      type: 'string'
    }
  },
  required: ['aTestProp']
}

const { withSchemaValidatorMiddleware } = createSchemaValidatorComponent()

router.post('/v1/test', withSchemaValidatorMiddleware(schema))

The component also exposes addSchema and validateSchema for validating payloads outside the middleware:

const validator = createSchemaValidatorComponent()

validator.addSchema(schema, 'my-schema')
const { valid, errors } = validator.validateSchema('my-schema', payload)

Options

| Option | Type | Default | Description | | ----------------------- | --------- | ------- | -------------------------------------------------------------------------------------------- | | ensureJsonContentType | boolean | true | When true, the middleware rejects requests whose Content-Type is not application/json. |

Notes

• Each call to withSchemaValidatorMiddleware registers the schema under a random key in the shared Ajv instance. Register middlewares once at startup rather than per request, otherwise registered schemas will accumulate in memory.
• A request whose Content-Type is not application/json is rejected with HTTP 415 Unsupported Media Type (values like application/json; charset=utf-8 are accepted).
• The middleware reads the entire request body into memory via request.clone().json(). To bound body size, put a body-size limit in front of it — the @dcl/http-server maxBodySize option or its createBodySizeLimitMiddleware, which cap the body at the transport layer while streaming.
• When the body read fails with an error that already carries an HTTP status/statusCode (for example a 413 raised by an upstream @dcl/http-server body-size limiter on a chunked body), the middleware surfaces that status rather than masking it as a generic 400. Errors without a status (genuine JSON parse failures) still return 400.
• addSchema replaces any schema already registered under the given key, so repeated calls (e.g. from a hot-reload path) are safe.