التواصل عبر HTTP (REST بين الخدمات)

import { ServiceNotFoundError, AuthenticationError } from './lib/base_repository';
import axios, { AxiosInstance } from 'axios';

// Anti-Corruption Layer — كل Provider له Client خاص به (Bulkhead)
const userServiceHttp: AxiosInstance = axios.create({
  baseURL: 'http://user-service:3001',
  timeout: 5000,
});

// Repository Protocol للمخدمات الخارجية
interface UserRepository {
  getUser(id: string): Promise<User>;
}

// Implementation — الطبقة الوحيدة التي تستورد axios مباشرة
class HttpUserRepository implements UserRepository {
  async getUser(id: string): Promise<User> {
    try {
      const { data } = await userServiceHttp.get(`/users/${id}`);
      return data;
    } catch (err) {
      if (axios.isAxiosError(err) && err.response?.status === 404) {
        throw new ServiceNotFoundError(`user/${id}`);
      }
      throw err;
    }
  }
}

// Service Layer — لا يعرف axios أو ORM
class UserService {
  constructor(private readonly userRepo: UserRepository) {}

  async getUser(id: string): Promise<User> {
    const user = await this.userRepo.getUser(id);
    if (!user.isActive) {
      throw new AuthenticationError(`User ${id} is deactivated`);
    }
    return user;
  }
}

const response = await axios.get('http://...', { timeout: 3000 });

async function withRetry(fn, retries = 3, delay = 1000) {
  for (let i = 0; i < retries; i++) {
    try {
      return await fn();
    } catch (err) {
      if (i === retries - 1) throw err;
      await new Promise(r => setTimeout(r, delay * Math.pow(2, i)));
    }
  }
}

import { DomainError } from './lib/base_repository';

// رمز خطأ موحد بين الخدمات — يرث من DomainError
class ServiceError extends DomainError {
  constructor(
    readonly code: string,
    message: string,
    readonly statusCode: number = 500,
  ) {
    super(message);
  }
}

openapi: 3.0.0
info:
  title: User Service
  version: 1.0.0
paths:
  /users/{id}:
    get:
      summary: الحصول على مستخدم
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: المستخدم المطلوب