# IMQBeforeCall interface · @imqueue/rpc

Source: https://imqueue.org/api/rpc/latest/rpc.imqbeforecall/
Published: 2026-08-04
Author: @imqueue maintainers (https://github.com/imqueue)
Package: @imqueue/rpc 3.5.3 — generated reference, not hand-written

Hook invoked before a call is dispatched.

**Signature:**

```typescript
export interface IMQBeforeCall<_T> 
```

## Remarks

On a service the hook receives `(request, response)`; on a client it receives `(request)` only, and `res` is always `undefined`.

Assigning `res.error` aborts the call — the method is never invoked and the error is returned to the caller. This is the supported way to reject a request from a hook. Assigning `res.data` has no effect, since it is overwritten by the method's result.

Throwing does not abort anything: the error is logged as a warning (see [BEFORE\_HOOK\_ERROR](https://imqueue.org/api/rpc/latest/rpc.before_hook_error/)) and dispatch proceeds.

The hook is invoked bound to the service or client instance, so a `function` expression can reach `this.logger` and `this.options` — but the type parameter is decorative, so `this` is not typed, and an arrow function does not receive the instance at all.