Exceptions

GamanJS menyediakan composeException untuk menangani error yang terjadi saat proses request. Exception handler bisa didaftarkan secara global (semua route) atau per-route.

Membuat Exception Handler

src/modules/app/exceptions/GlobalException.ts

import { composeException } from 'gaman/compose';

export default composeException((error, ctx) => {
  console.error(`[Error] ${ctx.path}:`, error.message);

  return ctx.send({
    error: error.message,
    path: ctx.path,
  }).error(); // 500
});

composeException menerima callback (error, ctx) => Response dan mengembalikan ExceptionHandler.

Global Exception Handler

Daftarkan di defineBootstrap via app.mount():

import { defineBootstrap } from 'gaman';
import router from './router';
import GlobalException from './modules/app/exceptions/GlobalException';

defineBootstrap(async (app) => {
  // Daftarkan global exception handler
  app.mount(GlobalException);

  app.mount(router);
  app.mountServer({ http: 3431 });
});

Global exception handler menangkap semua error yang tidak di-handle oleh exception handler per-route.

Per-Route Exception Handler

Override error handling untuk route spesifik:

import { composeRouter, composeException } from 'gaman/compose';
import PaymentController from './modules/app/controllers/PaymentController';

const PaymentErrorHandler = composeException((error, ctx) => {
  // Log ke external service
  console.error('[Payment Error]', error);

  return ctx.send({
    error: 'Payment processing failed',
    reference: ctx.request.id,
  }).error();
});

export default composeRouter((r) => {
  r.post('/payment/process', [PaymentController, 'Process'])
    .exception(PaymentErrorHandler);
});

Prioritas Exception Handler

Error terjadi di handler
    ↓
Ada per-route exception handler?
    → Ya: Gunakan per-route handler
    → Tidak: Ada global exception handler?
        → Ya: Gunakan global handler
        → Tidak: Return response 500 default

Contoh: Structured Error Handling

src/modules/app/exceptions/GlobalException.ts

import { composeException } from 'gaman/compose';

class AppError extends Error {
  constructor(
    message: string,
    public statusCode: number = 500,
    public errors?: Record<string, string[]>,
  ) {
    super(message);
  }
}

export default composeException((error, ctx) => {
  if (error instanceof AppError) {
    if (error.errors) {
      return ctx.send({
        message: error.message,
        errors: error.errors
      }).unprocessable();
    }
    return ctx.send({ message: error.message }).build(error.statusCode);
  }

  // Unknown error
  console.error('[Unhandled]', error);
  return ctx.send({ message: 'Internal Server Error' }).error();
});

Penggunaan di controller:

async Create(ctx) {
  const body = await ctx.json();

  if (!body.email) {
    throw new AppError('Validation failed', 422, {
      email: ['Email wajib diisi'],
    });
  }

  // ... logic
}