Agent skill

express-api-generator

Generates Express.js API routes with proper middleware, error handling, validation, and TypeScript support. Use when creating REST APIs or Express endpoints.

View SKILL.md on GitHub Repository
Stars 5
Forks 2

Install this agent skill to your Project

npx add-skill https://github.com/Dexploarer/claudius-skills/tree/main/examples/intermediate/framework-skills/express-api-generator

SKILL.md

Express.js API Generator Skill

Expert at creating well-structured Express.js APIs with TypeScript, proper error handling, and best practices.

When to Activate

  • "create Express API for [resource]"
  • "generate REST endpoints for [feature]"
  • "build Express routes for [entity]"
  • "scaffold Express API"

Complete API Structure

1. Router File

typescript
// routes/users.routes.ts
import { Router } from 'express';
import { UserController } from '../controllers/user.controller';
import { validate } from '../middleware/validation.middleware';
import { authenticate } from '../middleware/auth.middleware';
import { createUserSchema, updateUserSchema } from '../schemas/user.schema';

const router = Router();
const userController = new UserController();

// GET /api/users - List all users
router.get(
  '/',
  authenticate,
  userController.getAll
);

// GET /api/users/:id - Get user by ID
router.get(
  '/:id',
  authenticate,
  userController.getById
);

// POST /api/users - Create new user
router.post(
  '/',
  validate(createUserSchema),
  userController.create
);

// PUT /api/users/:id - Update user
router.put(
  '/:id',
  authenticate,
  validate(updateUserSchema),
  userController.update
);

// DELETE /api/users/:id - Delete user
router.delete(
  '/:id',
  authenticate,
  userController.delete
);

export default router;

2. Controller

typescript
// controllers/user.controller.ts
import { Request, Response, NextFunction } from 'express';
import { UserService } from '../services/user.service';
import { CreateUserDTO, UpdateUserDTO } from '../dto/user.dto';
import { ApiError } from '../utils/ApiError';
import { asyncHandler } from '../utils/asyncHandler';

export class UserController {
  private userService: UserService;

  constructor() {
    this.userService = new UserService();
  }

  getAll = asyncHandler(async (req: Request, res: Response) => {
    const { page = 1, limit = 10, search } = req.query;

    const result = await this.userService.getAll({
      page: Number(page),
      limit: Number(limit),
      search: search as string,
    });

    res.status(200).json({
      success: true,
      data: result.users,
      meta: {
        page: result.page,
        limit: result.limit,
        total: result.total,
        totalPages: Math.ceil(result.total / result.limit),
      },
    });
  });

  getById = asyncHandler(async (req: Request, res: Response) => {
    const { id } = req.params;

    const user = await this.userService.getById(id);

    if (!user) {
      throw new ApiError(404, 'User not found');
    }

    res.status(200).json({
      success: true,
      data: user,
    });
  });

  create = asyncHandler(async (req: Request, res: Response) => {
    const userData: CreateUserDTO = req.body;

    const user = await this.userService.create(userData);

    res.status(201).json({
      success: true,
      data: user,
      message: 'User created successfully',
    });
  });

  update = asyncHandler(async (req: Request, res: Response) => {
    const { id } = req.params;
    const userData: UpdateUserDTO = req.body;

    const user = await this.userService.update(id, userData);

    if (!user) {
      throw new ApiError(404, 'User not found');
    }

    res.status(200).json({
      success: true,
      data: user,
      message: 'User updated successfully',
    });
  });

  delete = asyncHandler(async (req: Request, res: Response) => {
    const { id } = req.params;

    await this.userService.delete(id);

    res.status(200).json({
      success: true,
      message: 'User deleted successfully',
    });
  });
}

3. Service Layer

typescript
// services/user.service.ts
import { User } from '../models/user.model';
import { CreateUserDTO, UpdateUserDTO } from '../dto/user.dto';
import { ApiError } from '../utils/ApiError';
import bcrypt from 'bcrypt';

interface GetAllOptions {
  page: number;
  limit: number;
  search?: string;
}

export class UserService {
  async getAll(options: GetAllOptions) {
    const { page, limit, search } = options;
    const skip = (page - 1) * limit;

    const query = search
      ? { $or: [
          { name: { $regex: search, $options: 'i' } },
          { email: { $regex: search, $options: 'i' } },
        ]}
      : {};

    const [users, total] = await Promise.all([
      User.find(query).skip(skip).limit(limit).select('-password'),
      User.countDocuments(query),
    ]);

    return { users, total, page, limit };
  }

  async getById(id: string) {
    const user = await User.findById(id).select('-password');
    return user;
  }

  async create(userData: CreateUserDTO) {
    const existingUser = await User.findOne({ email: userData.email });

    if (existingUser) {
      throw new ApiError(409, 'Email already exists');
    }

    const hashedPassword = await bcrypt.hash(userData.password, 10);

    const user = await User.create({
      ...userData,
      password: hashedPassword,
    });

    const userObject = user.toObject();
    delete userObject.password;

    return userObject;
  }

  async update(id: string, userData: UpdateUserDTO) {
    if (userData.password) {
      userData.password = await bcrypt.hash(userData.password, 10);
    }

    const user = await User.findByIdAndUpdate(
      id,
      { $set: userData },
      { new: true, runValidators: true }
    ).select('-password');

    return user;
  }

  async delete(id: string) {
    const user = await User.findByIdAndDelete(id);

    if (!user) {
      throw new ApiError(404, 'User not found');
    }

    return true;
  }
}

4. Validation Schema

typescript
// schemas/user.schema.ts
import Joi from 'joi';

export const createUserSchema = Joi.object({
  name: Joi.string().min(2).max(100).required(),
  email: Joi.string().email().required(),
  password: Joi.string().min(8).required(),
  role: Joi.string().valid('user', 'admin').default('user'),
});

export const updateUserSchema = Joi.object({
  name: Joi.string().min(2).max(100),
  email: Joi.string().email(),
  password: Joi.string().min(8),
  role: Joi.string().valid('user', 'admin'),
}).min(1);

5. Middleware

typescript
// middleware/validation.middleware.ts
import { Request, Response, NextFunction } from 'express';
import { Schema } from 'joi';
import { ApiError } from '../utils/ApiError';

export const validate = (schema: Schema) => {
  return (req: Request, res: Response, next: NextFunction) => {
    const { error, value } = schema.validate(req.body, {
      abortEarly: false,
      stripUnknown: true,
    });

    if (error) {
      const message = error.details.map(d => d.message).join(', ');
      throw new ApiError(400, message);
    }

    req.body = value;
    next();
  };
};
typescript
// middleware/auth.middleware.ts
import { Request, Response, NextFunction } from 'express';
import jwt from 'jsonwebtoken';
import { ApiError } from '../utils/ApiError';

interface JwtPayload {
  userId: string;
  email: string;
}

declare global {
  namespace Express {
    interface Request {
      user?: JwtPayload;
    }
  }
}

export const authenticate = (req: Request, res: Response, next: NextFunction) => {
  const token = req.headers.authorization?.replace('Bearer ', '');

  if (!token) {
    throw new ApiError(401, 'Authentication required');
  }

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET!) as JwtPayload;
    req.user = decoded;
    next();
  } catch (error) {
    throw new ApiError(401, 'Invalid or expired token');
  }
};

6. Error Handler

typescript
// utils/ApiError.ts
export class ApiError extends Error {
  constructor(
    public statusCode: number,
    public message: string,
    public errors: any[] = []
  ) {
    super(message);
    this.name = 'ApiError';
  }
}

// utils/asyncHandler.ts
import { Request, Response, NextFunction } from 'express';

export const asyncHandler = (fn: Function) => {
  return (req: Request, res: Response, next: NextFunction) => {
    Promise.resolve(fn(req, res, next)).catch(next);
  };
};

// middleware/errorHandler.ts
import { Request, Response, NextFunction } from 'express';
import { ApiError } from '../utils/ApiError';

export const errorHandler = (
  err: Error,
  req: Request,
  res: Response,
  next: NextFunction
) => {
  if (err instanceof ApiError) {
    return res.status(err.statusCode).json({
      success: false,
      message: err.message,
      errors: err.errors,
    });
  }

  console.error('Unexpected error:', err);

  res.status(500).json({
    success: false,
    message: 'Internal server error',
  });
};

File Structure

src/
├── routes/
│   └── user.routes.ts
├── controllers/
│   └── user.controller.ts
├── services/
│   └── user.service.ts
├── models/
│   └── user.model.ts
├── dto/
│   └── user.dto.ts
├── schemas/
│   └── user.schema.ts
├── middleware/
│   ├── auth.middleware.ts
│   ├── validation.middleware.ts
│   └── errorHandler.ts
└── utils/
    ├── ApiError.ts
    └── asyncHandler.ts

Best Practices

  • ✅ Separate routes, controllers, and services
  • ✅ Use TypeScript for type safety
  • ✅ Implement proper error handling
  • ✅ Validate input data
  • ✅ Use async/await with error handling
  • ✅ Implement authentication/authorization
  • ✅ Return consistent response format
  • ✅ Add pagination for list endpoints
  • ✅ Use HTTP status codes correctly
  • ✅ Handle edge cases
  • ✅ Add request logging
  • ✅ Implement rate limiting

Output Checklist

  • ✅ Routes file created
  • ✅ Controller implemented
  • ✅ Service layer added
  • ✅ Validation schemas defined
  • ✅ Middleware configured
  • ✅ Error handling setup
  • ✅ Tests created
  • 📝 API documentation provided

Recommended Agent Skills

Expand your agent's capabilities with these related and highly-rated skills.

Dexploarer/claudius-skills

smart-contract-generator

Generates Solidity smart contracts with security best practices (ERC-20, ERC-721, ERC-1155, custom). Use when user asks to "create smart contract", "solidity contract", "erc20 token", "nft contract", or "web3 contract".

5 2
Explore
Dexploarer/claudius-skills

threejs-scene-builder

Comprehensive Three.js and React Three Fiber skill for creating 3D scenes, characters, NPCs, procedural generation, animation retargeting, and interactive experiences. Use when user asks to "create Three.js scene", "setup React Three Fiber", "add 3D character", "create NPC AI", "procedural 3D generation", "retarget animation", "setup avatar system", or "create 3D game".

5 2
Explore
Dexploarer/claudius-skills

wcag-compliance-checker

Checks websites for WCAG 2.1 Level AA compliance, identifies accessibility violations, and provides remediation guidance. Use when user asks to "check accessibility", "wcag compliance", "a11y audit", "accessibility violations", or "screen reader testing".

5 2
Explore
Dexploarer/claudius-skills

kubernetes-manifest-generator

Generates Kubernetes manifests (Deployments, Services, Ingress, ConfigMaps, Secrets) with best practices for production workloads. Use when user asks to "create k8s manifest", "generate Kubernetes deployment", "setup k8s service", or "create Kubernetes resources".

5 2
Explore
Dexploarer/claudius-skills

terraform-module-builder

Generates reusable Terraform modules with best practices for AWS, Azure, GCP infrastructure as code. Use when user asks to "create Terraform module", "generate IaC module", "setup Terraform", or "create infrastructure module".

5 2
Explore
Dexploarer/claudius-skills

translation-key-extractor

Extracts hardcoded strings from code and converts them to translation keys for i18n. Use when user asks to "extract translations", "find hardcoded strings", "internationalize code", "setup i18n", or "create translation files".

5 2
Explore

Didn't find tool you were looking for?

Be as detailed as possible for better results