This commit is contained in:
@@ -0,0 +1,430 @@
|
||||
# Node.js Advanced Patterns
|
||||
|
||||
Advanced patterns for dependency injection, database integration, authentication, caching, and API response formatting.
|
||||
|
||||
## Dependency Injection
|
||||
|
||||
### DI Container
|
||||
|
||||
```typescript
|
||||
// di-container.ts
|
||||
import { Pool } from "pg";
|
||||
import { UserRepository } from "./repositories/user.repository";
|
||||
import { UserService } from "./services/user.service";
|
||||
import { UserController } from "./controllers/user.controller";
|
||||
import { AuthService } from "./services/auth.service";
|
||||
|
||||
class Container {
|
||||
private instances = new Map<string, any>();
|
||||
|
||||
register<T>(key: string, factory: () => T): void {
|
||||
this.instances.set(key, factory);
|
||||
}
|
||||
|
||||
resolve<T>(key: string): T {
|
||||
const factory = this.instances.get(key);
|
||||
if (!factory) {
|
||||
throw new Error(`No factory registered for ${key}`);
|
||||
}
|
||||
return factory();
|
||||
}
|
||||
|
||||
singleton<T>(key: string, factory: () => T): void {
|
||||
let instance: T;
|
||||
this.instances.set(key, () => {
|
||||
if (!instance) {
|
||||
instance = factory();
|
||||
}
|
||||
return instance;
|
||||
});
|
||||
}
|
||||
}
|
||||
|
||||
export const container = new Container();
|
||||
|
||||
// Register dependencies
|
||||
container.singleton(
|
||||
"db",
|
||||
() =>
|
||||
new Pool({
|
||||
host: process.env.DB_HOST,
|
||||
port: parseInt(process.env.DB_PORT || "5432"),
|
||||
database: process.env.DB_NAME,
|
||||
user: process.env.DB_USER,
|
||||
password: process.env.DB_PASSWORD,
|
||||
max: 20,
|
||||
idleTimeoutMillis: 30000,
|
||||
connectionTimeoutMillis: 2000,
|
||||
}),
|
||||
);
|
||||
|
||||
container.singleton(
|
||||
"userRepository",
|
||||
() => new UserRepository(container.resolve("db")),
|
||||
);
|
||||
|
||||
container.singleton(
|
||||
"userService",
|
||||
() => new UserService(container.resolve("userRepository")),
|
||||
);
|
||||
|
||||
container.register(
|
||||
"userController",
|
||||
() => new UserController(container.resolve("userService")),
|
||||
);
|
||||
|
||||
container.singleton(
|
||||
"authService",
|
||||
() => new AuthService(container.resolve("userRepository")),
|
||||
);
|
||||
```
|
||||
|
||||
## Database Patterns
|
||||
|
||||
### PostgreSQL with Connection Pool
|
||||
|
||||
```typescript
|
||||
// config/database.ts
|
||||
import { Pool, PoolConfig } from "pg";
|
||||
|
||||
const poolConfig: PoolConfig = {
|
||||
host: process.env.DB_HOST,
|
||||
port: parseInt(process.env.DB_PORT || "5432"),
|
||||
database: process.env.DB_NAME,
|
||||
user: process.env.DB_USER,
|
||||
password: process.env.DB_PASSWORD,
|
||||
max: 20,
|
||||
idleTimeoutMillis: 30000,
|
||||
connectionTimeoutMillis: 2000,
|
||||
};
|
||||
|
||||
export const pool = new Pool(poolConfig);
|
||||
|
||||
// Test connection
|
||||
pool.on("connect", () => {
|
||||
console.log("Database connected");
|
||||
});
|
||||
|
||||
pool.on("error", (err) => {
|
||||
console.error("Unexpected database error", err);
|
||||
process.exit(-1);
|
||||
});
|
||||
|
||||
// Graceful shutdown
|
||||
export const closeDatabase = async () => {
|
||||
await pool.end();
|
||||
console.log("Database connection closed");
|
||||
};
|
||||
```
|
||||
|
||||
### MongoDB with Mongoose
|
||||
|
||||
```typescript
|
||||
// config/mongoose.ts
|
||||
import mongoose from "mongoose";
|
||||
|
||||
const connectDB = async () => {
|
||||
try {
|
||||
await mongoose.connect(process.env.MONGODB_URI!, {
|
||||
maxPoolSize: 10,
|
||||
serverSelectionTimeoutMS: 5000,
|
||||
socketTimeoutMS: 45000,
|
||||
});
|
||||
|
||||
console.log("MongoDB connected");
|
||||
} catch (error) {
|
||||
console.error("MongoDB connection error:", error);
|
||||
process.exit(1);
|
||||
}
|
||||
};
|
||||
|
||||
mongoose.connection.on("disconnected", () => {
|
||||
console.log("MongoDB disconnected");
|
||||
});
|
||||
|
||||
mongoose.connection.on("error", (err) => {
|
||||
console.error("MongoDB error:", err);
|
||||
});
|
||||
|
||||
export { connectDB };
|
||||
|
||||
// Model example
|
||||
import { Schema, model, Document } from "mongoose";
|
||||
|
||||
interface IUser extends Document {
|
||||
name: string;
|
||||
email: string;
|
||||
password: string;
|
||||
createdAt: Date;
|
||||
updatedAt: Date;
|
||||
}
|
||||
|
||||
const userSchema = new Schema<IUser>(
|
||||
{
|
||||
name: { type: String, required: true },
|
||||
email: { type: String, required: true, unique: true },
|
||||
password: { type: String, required: true },
|
||||
},
|
||||
{
|
||||
timestamps: true,
|
||||
},
|
||||
);
|
||||
|
||||
// Indexes
|
||||
userSchema.index({ email: 1 });
|
||||
|
||||
export const User = model<IUser>("User", userSchema);
|
||||
```
|
||||
|
||||
### Transaction Pattern
|
||||
|
||||
```typescript
|
||||
// services/order.service.ts
|
||||
import { Pool } from "pg";
|
||||
|
||||
export class OrderService {
|
||||
constructor(private db: Pool) {}
|
||||
|
||||
async createOrder(userId: string, items: any[]) {
|
||||
const client = await this.db.connect();
|
||||
|
||||
try {
|
||||
await client.query("BEGIN");
|
||||
|
||||
// Create order
|
||||
const orderResult = await client.query(
|
||||
"INSERT INTO orders (user_id, total) VALUES ($1, $2) RETURNING id",
|
||||
[userId, calculateTotal(items)],
|
||||
);
|
||||
const orderId = orderResult.rows[0].id;
|
||||
|
||||
// Create order items
|
||||
for (const item of items) {
|
||||
await client.query(
|
||||
"INSERT INTO order_items (order_id, product_id, quantity, price) VALUES ($1, $2, $3, $4)",
|
||||
[orderId, item.productId, item.quantity, item.price],
|
||||
);
|
||||
|
||||
// Update inventory
|
||||
await client.query(
|
||||
"UPDATE products SET stock = stock - $1 WHERE id = $2",
|
||||
[item.quantity, item.productId],
|
||||
);
|
||||
}
|
||||
|
||||
await client.query("COMMIT");
|
||||
return orderId;
|
||||
} catch (error) {
|
||||
await client.query("ROLLBACK");
|
||||
throw error;
|
||||
} finally {
|
||||
client.release();
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Authentication & Authorization
|
||||
|
||||
### JWT Authentication
|
||||
|
||||
```typescript
|
||||
// services/auth.service.ts
|
||||
import jwt from "jsonwebtoken";
|
||||
import bcrypt from "bcrypt";
|
||||
import { UserRepository } from "../repositories/user.repository";
|
||||
import { UnauthorizedError } from "../utils/errors";
|
||||
|
||||
export class AuthService {
|
||||
constructor(private userRepository: UserRepository) {}
|
||||
|
||||
async login(email: string, password: string) {
|
||||
const user = await this.userRepository.findByEmail(email);
|
||||
|
||||
if (!user) {
|
||||
throw new UnauthorizedError("Invalid credentials");
|
||||
}
|
||||
|
||||
const isValid = await bcrypt.compare(password, user.password);
|
||||
|
||||
if (!isValid) {
|
||||
throw new UnauthorizedError("Invalid credentials");
|
||||
}
|
||||
|
||||
const token = this.generateToken({
|
||||
userId: user.id,
|
||||
email: user.email,
|
||||
});
|
||||
|
||||
const refreshToken = this.generateRefreshToken({
|
||||
userId: user.id,
|
||||
});
|
||||
|
||||
return {
|
||||
token,
|
||||
refreshToken,
|
||||
user: {
|
||||
id: user.id,
|
||||
name: user.name,
|
||||
email: user.email,
|
||||
},
|
||||
};
|
||||
}
|
||||
|
||||
async refreshToken(refreshToken: string) {
|
||||
try {
|
||||
const payload = jwt.verify(
|
||||
refreshToken,
|
||||
process.env.REFRESH_TOKEN_SECRET!,
|
||||
) as { userId: string };
|
||||
|
||||
const user = await this.userRepository.findById(payload.userId);
|
||||
|
||||
if (!user) {
|
||||
throw new UnauthorizedError("User not found");
|
||||
}
|
||||
|
||||
const token = this.generateToken({
|
||||
userId: user.id,
|
||||
email: user.email,
|
||||
});
|
||||
|
||||
return { token };
|
||||
} catch (error) {
|
||||
throw new UnauthorizedError("Invalid refresh token");
|
||||
}
|
||||
}
|
||||
|
||||
private generateToken(payload: any): string {
|
||||
return jwt.sign(payload, process.env.JWT_SECRET!, {
|
||||
expiresIn: "15m",
|
||||
});
|
||||
}
|
||||
|
||||
private generateRefreshToken(payload: any): string {
|
||||
return jwt.sign(payload, process.env.REFRESH_TOKEN_SECRET!, {
|
||||
expiresIn: "7d",
|
||||
});
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Caching Strategies
|
||||
|
||||
```typescript
|
||||
// utils/cache.ts
|
||||
import Redis from "ioredis";
|
||||
|
||||
const redis = new Redis({
|
||||
host: process.env.REDIS_HOST,
|
||||
port: parseInt(process.env.REDIS_PORT || "6379"),
|
||||
retryStrategy: (times) => {
|
||||
const delay = Math.min(times * 50, 2000);
|
||||
return delay;
|
||||
},
|
||||
});
|
||||
|
||||
export class CacheService {
|
||||
async get<T>(key: string): Promise<T | null> {
|
||||
const data = await redis.get(key);
|
||||
return data ? JSON.parse(data) : null;
|
||||
}
|
||||
|
||||
async set(key: string, value: any, ttl?: number): Promise<void> {
|
||||
const serialized = JSON.stringify(value);
|
||||
if (ttl) {
|
||||
await redis.setex(key, ttl, serialized);
|
||||
} else {
|
||||
await redis.set(key, serialized);
|
||||
}
|
||||
}
|
||||
|
||||
async delete(key: string): Promise<void> {
|
||||
await redis.del(key);
|
||||
}
|
||||
|
||||
async invalidatePattern(pattern: string): Promise<void> {
|
||||
const keys = await redis.keys(pattern);
|
||||
if (keys.length > 0) {
|
||||
await redis.del(...keys);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Cache decorator
|
||||
export function Cacheable(ttl: number = 300) {
|
||||
return function (
|
||||
target: any,
|
||||
propertyKey: string,
|
||||
descriptor: PropertyDescriptor,
|
||||
) {
|
||||
const originalMethod = descriptor.value;
|
||||
|
||||
descriptor.value = async function (...args: any[]) {
|
||||
const cache = new CacheService();
|
||||
const cacheKey = `${propertyKey}:${JSON.stringify(args)}`;
|
||||
|
||||
const cached = await cache.get(cacheKey);
|
||||
if (cached) {
|
||||
return cached;
|
||||
}
|
||||
|
||||
const result = await originalMethod.apply(this, args);
|
||||
await cache.set(cacheKey, result, ttl);
|
||||
|
||||
return result;
|
||||
};
|
||||
|
||||
return descriptor;
|
||||
};
|
||||
}
|
||||
```
|
||||
|
||||
## API Response Format
|
||||
|
||||
```typescript
|
||||
// utils/response.ts
|
||||
import { Response } from "express";
|
||||
|
||||
export class ApiResponse {
|
||||
static success<T>(
|
||||
res: Response,
|
||||
data: T,
|
||||
message?: string,
|
||||
statusCode = 200,
|
||||
) {
|
||||
return res.status(statusCode).json({
|
||||
status: "success",
|
||||
message,
|
||||
data,
|
||||
});
|
||||
}
|
||||
|
||||
static error(res: Response, message: string, statusCode = 500, errors?: any) {
|
||||
return res.status(statusCode).json({
|
||||
status: "error",
|
||||
message,
|
||||
...(errors && { errors }),
|
||||
});
|
||||
}
|
||||
|
||||
static paginated<T>(
|
||||
res: Response,
|
||||
data: T[],
|
||||
page: number,
|
||||
limit: number,
|
||||
total: number,
|
||||
) {
|
||||
return res.json({
|
||||
status: "success",
|
||||
data,
|
||||
pagination: {
|
||||
page,
|
||||
limit,
|
||||
total,
|
||||
pages: Math.ceil(total / limit),
|
||||
},
|
||||
});
|
||||
}
|
||||
}
|
||||
```
|
||||
Reference in New Issue
Block a user