Type-Safe Events

Events are strongly typed and validated across the supported runtimes. Repository example files:

Python
TypeScript
Rust
Go

from typing import Any
from abxbus import BaseEvent

class OrderCreatedEvent(BaseEvent[dict[str, Any]]):
    order_id: str
    customer_id: str
    total_amount: float

import { BaseEvent } from 'abxbus'
import { z } from 'zod'

const OrderCreatedEvent = BaseEvent.extend('OrderCreatedEvent', {
  order_id: z.string(),
  customer_id: z.string(),
  total_amount: z.number(),
  event_result_type: z.object({ ok: z.boolean() }),
})

use abxbus::{
    event,
    event_bus::EventBus,
    BaseEvent,
};
use futures::executor::block_on;
use serde::{Deserialize, Serialize};

#[derive(Clone, Serialize, Deserialize, PartialEq, Debug)]
struct OrderResult {
    ok: bool,
}

event! {
    struct OrderCreatedEvent {
        order_id: String,
        customer_id: String,
        total_amount: f64,
        event_result_type: OrderResult,
        event_result_schema: r#"{
            "type": "object",
            "properties": {"ok": {"type": "boolean"}},
            "required": ["ok"]
        }"#,
    }
}

let bus = EventBus::new(Some("OrdersBus".to_string()));
bus.on(OrderCreatedEvent, |event: OrderCreatedEvent| async move {
    Ok(OrderResult {
        ok: event.total_amount > 0.0,
    })
});

let event = bus.emit(OrderCreatedEvent {
    order_id: "order-123".to_string(),
    customer_id: "customer-456".to_string(),
    total_amount: 42.50,
    ..Default::default()
});

let typed_result = block_on(event.event_result())?
    .expect("handler result");

type OrderCreatedEvent struct {
	OrderID     string  `json:"order_id"`
	CustomerID  string  `json:"customer_id"`
	TotalAmount float64 `json:"total_amount"`
}

type OrderResult struct {
	OK bool `json:"ok"`
}

bus := abxbus.NewEventBus("OrdersBus", nil)
bus.On(func(event OrderCreatedEvent) (OrderResult, error) {
	return OrderResult{OK: event.TotalAmount > 0}, nil
})

result, err := bus.Emit(OrderCreatedEvent{
	OrderID:     "order-123",
	CustomerID:  "customer-456",
	TotalAmount: 42.50,
}).EventResult()
if err != nil {
	panic(err)
}
typedResult, err := abxbus.EventResultAs[OrderResult](result)
if err != nil {
	panic(err)
}
_ = typedResult

Python payload validation is powered by Pydantic models.
TypeScript payload and result validation is powered by Zod schemas.
Rust uses event! to keep event fields and event metadata in one block. Primitive result schemas are derived automatically; structured result schemas are supplied through event_result_schema.
Go uses typed struct helpers for static shape at call sites, validates typed handler payloads against the declared payload struct, and derives JSON Schema from the declared result type for runtime result validation.

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Type-Safe Events