Crudy

A CRUD generator for Express.js with PostgreSQL that automatically detects table schemas and handles relations.

Features

• 🚀 Auto-detect schemas from PostgreSQL database (lazy loading - no database calls on creation)
• 🔗 Automatic relation detection from foreign keys
• 📦 Multi-table support - generate CRUD for multiple tables at once
• 🔍 Related data inclusion - GET requests automatically include related records
• 🛡️ Smart delete protection - shows which records are blocking deletions
• ⚡ Zero configuration - just pass table names

Installation

npm install github:eduardomagaldi/crudy
npm install pg express

Quick Start

const express = require('express')
const { Pool } = require('pg')
const createCrudyMulti = require('crudy')

const pool = new Pool({
  user: 'your_user',
  host: 'localhost',
  database: 'your_database',
  password: 'your_password',
  port: 5432,
})

const app = express()
app.use(express.json())

// ⚡ No await needed! createCrudyMulti is synchronous
// Schemas are loaded lazily on first request
const handlers = createCrudyMulti(['users', 'addresses', 'purchases'], pool)

// Response middleware
const sendResponse = (req, res) => {
  const status = res.locals.crudyStatus || 200
  const result = res.locals.crudyResult
  if (status === 204) return res.status(204).send()
  res.status(status).json(result)
}

// Set up routes
app.get('/users', handlers.users.handleGetAll, sendResponse)
app.get('/users/:id', handlers.users.handleGet, sendResponse)
app.post('/users', handlers.users.handleCreate, sendResponse)
app.put('/users/:id', handlers.users.handleUpdate, sendResponse)
app.delete('/users/:id', handlers.users.handleDelete, sendResponse)

// Repeat for other tables: handlers.addresses.*, handlers.purchases.*

app.listen(3000, () => {
  console.log('Server running on http://localhost:3000')
})

How It Works

Lazy Schema Loading

No database calls on creation! Schemas are automatically loaded and cached in memory on the first request. This means:

• ✅ Instant handler creation (synchronous, no await)
• ✅ Schemas cached as singleton (one query per table)
• ✅ Fast subsequent requests

Schema Auto-Detection

Crudy automatically detects:

• Column types, primary keys, foreign keys, auto-increment, required/optional fields

Relation Detection

Relations are automatically detected from:

1. Foreign key constraints
2. Column patterns (e.g., user_id → users table)

Relation Types:

• belongsTo - Included as singular property: address.user
• hasMany - Included as plural property: user.addresses

API

createCrudyMulti(tableNames, db)

Creates CRUD handlers for multiple tables. Synchronous - no await needed!

Parameters:

• tableNames (string[]) - Array of table names
• db (pg.Pool) - PostgreSQL connection pool

Returns: Object with table names as keys, each containing:

• handleGetAll(req, res, next) - Get all records
• handleGet(req, res, next) - Get single record by ID
• handleCreate(req, res, next) - Create new record
• handleUpdate(req, res, next) - Update record by ID
• handleDelete(req, res, next) - Delete record by ID
• tableName - Table name
• schema - Schema object (available after first request)

Response Format

GET with Relations

{
  "id": 1,
  "email": "[email protected]",
  "addresses": [{ "id": 1, "street": "123 Main St", "user_id": 1 }],
  "user": { "id": 1, "email": "[email protected]" }
}

DELETE with Relations

If deleting a record referenced by others:

{
  "error": "Cannot delete: this record is referenced by other records",
  "details": "2 record(s) in 'addresses' table (IDs: 1, 2)"
}

Status: 409 Conflict

Query Parameters

Filter results using query parameters:

GET /[email protected]&is_active=true

Error Handling

Handlers set response data in res.locals:

• res.locals.crudyStatus - HTTP status code
• res.locals.crudyResult - Response data or error object

Status codes: 200 (Success), 201 (Created), 204 (No Content), 404 (Not Found), 409 (Conflict), 500 (Server Error)

Requirements

• Node.js 14+
• PostgreSQL database
• pg package (peer dependency)
• express package

License

ISC