Access zod IO schema in middleware

[noahdamiani]

Is it possible to access the IO schema as a callback parameter in middleware? I scrolled through all the properties of the request, response, and input params given by the middleware callback but did not see anything schema related, hoping I missed something. Outlining what I am trying to do below:

const middleware = createMiddleware({
  input: z.object({}),
  async middleware({ request, response }) {
    // Middleware is attached to each route, so in theory it would be possible 
    // to resolve the input/output schema for a given route?
    // i.e. request.route.input // request.route.output

    return doStuffWithZodModel(request.route.input)
  },
});

const withSchemaMiddleware = defaultEndpointsFactory.addMiddleware(middleware);

const helloWorldEndpoint = withSchemaMiddleware.build({
     ...
});

[RobinTail]

Hello @noahdamiani ,

I don't understand the use-case.
What are you trying to achieve exactly?

Handlers of the both Middleware and Endpoint do not receive the schema — they receive the parsed and validated input data.

However, it's easy for the handler to be aware of the schema — just declare it in a const in outer scope.

const mySchema = z.object({ /* ... */ });

const myMiddleware = createMiddleware({
  input: mySchema,
  middleware: async () => {
    return doYourStuff( mySchema )
  }
})

[noahdamiani]

I'm hoping to use the routes config as a mapping to retrieve a request schema given an endpoint uri. The example you've provided defines a model explicitly, whereas I am trying to retrieve the model dynamically. It sounds like middleware is not aware of the endpoint object or the uri provided in the routes config - I was hoping to access those in the middleware callback.

[RobinTail]

@noahdamiani , zod is a static type validator. The input schema assigned to the middleware or endpoint can not be dynamic. It can only be loose enough to fit all the variations, for example using .or() or using some refinement, based on the data being parsed.