Payload validation

You can use different validators in Hemera. A very popular and easy readable validator is Joi. Just install the hemera-joi package.

Joi validator

const Joi = hemera.joi
hemera.add(
  {
    topic: 'math',
    cmd: 'add',
    a: Joi.number().required(),
    b: Joi.number().required()
  },
  function(req, cb) {
    cb(null, req.a + req.b)
  }
)

JSON Schema

You can also use JSON-Schema. Just install the hemera-ajv package.

hemera.add(
  {
    topic: 'math',
    cmd: 'add',
    properties: {
      a: { type: 'number' },
      b: { type: 'number' }
    }
  },
  (req, cb) => {
    cb(null, req.a + req.b)
  }
)

Use your custom validator

We provide two methods setSchemaCompiler and setResponseSchemaCompiler which accepts a validation function. If you working with async validators you can return a promise as well.

hemera.setSchemaCompiler(schema => pattern =>
  return {
    error: new Error('invalid request payload')
  }
)
hemera.setResponseSchemaCompiler(schema => payload =>
  return {
    error: new Error('invalid response payload')
  }
)