@alt-javascript/boot-azure-function

Azure Functions adapter for the @alt-javascript framework. Handles Azure Functions v4 HTTP trigger requests with CDI-managed controllers and a CDI middleware pipeline for cross-cutting concerns.

Part of the @alt-javascript monorepo.

Install

npm install @alt-javascript/boot-azure-function

Usage

// function/handler.js
import { Boot } from '@alt-javascript/boot';
import { Context, Singleton } from '@alt-javascript/cdi';
import { azureFunctionStarter } from '@alt-javascript/boot-azure-function';
import { TodoService } from './services.js';
import { TodoController } from './controllers.js';

const context = new Context([
  ...azureFunctionStarter(),
  new Singleton(TodoService),
  new Singleton(TodoController),
]);

const appCtxPromise = Boot.boot({ contexts: [context], run: false });

export async function handler(request, invocationContext) {
  const appCtx = await appCtxPromise;
  return appCtx.get('azureFunctionAdapter').handle(request, invocationContext);
}

Controller Convention

class TodoController {
  static __routes = [
    { method: 'GET',  path: '/todos',     handler: 'list'   },
    { method: 'POST', path: '/todos',     handler: 'create' },
    { method: 'GET',  path: '/todos/:id', handler: 'get'    },
  ];

  constructor() { this.todoService = null; } // autowired

  async list(request)   { return this.todoService.findAll(); }
  async create(request) { return this.todoService.create(request.body); }
  async get(request)    { return this.todoService.findById(request.params.id); }
}

Handlers return a plain object (200), { statusCode, body } (explicit), or null / undefined (204). The adapter returns Azure Functions v4 HttpResponseInit: { status, jsonBody, headers }.

Middleware Pipeline

azureFunctionStarter() registers three built-in middleware components:

| Component | Order | Behaviour | |---|---|---| | RequestLoggerMiddleware | 10 | Logs [METHOD] /path → status (Xms) | | ErrorHandlerMiddleware | 20 | Converts thrown errors to JSON error responses | | NotFoundMiddleware | 30 | Returns 404 for unmatched routes |

Add custom middleware by declaring static __middleware = { order: N }:

class AuthMiddleware {
  static __middleware = { order: 5 };

  async handle(request, next) {
    const token = request.headers.authorization?.replace('Bearer ', '');
    if (!token) return { statusCode: 401, body: { error: 'Unauthorized' } };
    return next({ ...request, user: { token } });
  }
}

Configuration

| Key | Default | Description | |---|---|---| | middleware.requestLogger.enabled | true | Enable request logging | | middleware.errorHandler.enabled | true | Enable error handler | | middleware.notFound.enabled | true | Enable 404 handler |

License

MIT