codesnips

express

typescript 
export class AppError extends Error {
  public readonly statusCode: number;
  public readonly code: string;
  public readonly isOperational: boolean;

  constructor(message: string, statusCode = 500, code = 'INTERNAL_ERROR', isOperational = true) {

Backend: normalize errors with a single Express handler

express error-handling typescript
by codesnips 4 tabs
javascript 
const crypto = require('crypto');

function computeSignature(secret, timestamp, payload) {
  return crypto
    .createHmac('sha256', secret)
    .update(`${timestamp}.${payload}`, 'utf8')

Verify Stripe-Style Webhook Signatures With HMAC in Express Before Processing

webhooks hmac security
by codesnips 2 tabs
javascript 
const express = require('express');
const { toCsv } = require('./csvSerializer');
const { fetchOrders } = require('./orderRepository');

const router = express.Router();

Content Negotiation in Express: Serve JSON or CSV From One Route

express content-negotiation rest-api
by codesnips 3 tabs
typescript 
import { Response } from 'express';

type Client = { id: number; res: Response };

const clients = new Map<string, Set<Client>>();
let nextId = 1;

SSE endpoint for server-to-browser events

realtime sse express
by codesnips 3 tabs
javascript 
const { Pool } = require('pg');
const Cursor = require('pg-cursor');

const pool = new Pool();

async function* streamUsers({ since, batchSize = 500 }) {

Stream a Large JSON Array Response in Node.js Without Buffering

nodejs streams transform-stream
by codesnips 3 tabs
javascript 
const sharp = require('sharp');

const DEFAULTS = {
  maxWidth: 1600,
  maxHeight: 1600,
  format: 'webp',

Resize and Compress Uploaded Images with Sharp Before Saving to Disk

nodejs express sharp
by codesnips 3 tabs
lua 
-- KEYS[1] = current window key, KEYS[2] = previous window key
-- ARGV: limit, window_ms, elapsed_ms
local limit = tonumber(ARGV[1])
local window = tonumber(ARGV[2])
local elapsed = tonumber(ARGV[3])

Sliding-Window Rate Limiting for Express Routes Backed by Redis

express redis rate-limiting
by codesnips 4 tabs
sql 
CREATE TABLE idempotency_keys (
    id              BIGSERIAL PRIMARY KEY,
    idempotency_key TEXT        NOT NULL,
    request_path    TEXT        NOT NULL,
    request_fingerprint TEXT    NOT NULL,
    status          TEXT        NOT NULL DEFAULT 'in_progress',

Idempotent POST Requests with an Idempotency-Key Middleware in Express

express idempotency middleware
by codesnips 3 tabs
typescript 
const rawOrigins = process.env.ALLOWED_ORIGINS ?? "";

export const allowedOrigins = new Set(
  rawOrigins
    .split(",")
    .map((o) => o.trim())

CORS configuration that’s explicit (no *)

security http express
by codesnips 3 tabs
javascript 
class TokenBucket {
  constructor(capacity, refillPerSecond) {
    this.capacity = capacity;
    this.refillPerMs = refillPerSecond / 1000;
    this.tokens = capacity;
    this.lastRefill = Date.now();

Token Bucket Rate Limiter Middleware for Express with Per-Key Buckets

nodejs express rate-limiting
by codesnips 4 tabs
typescript 
import sharp from 'sharp';

export interface Variant {
  name: string;
  width: number;
  quality: number;

Generate WebP Image Thumbnails on Upload with Sharp and Express

express sharp image-processing
by codesnips 3 tabs
javascript 
const jwt = require('jsonwebtoken');

const ACCESS_SECRET = process.env.JWT_ACCESS_SECRET;
const REFRESH_SECRET = process.env.JWT_REFRESH_SECRET;
const ISSUER = 'api.example.com';
const AUDIENCE = 'example-web';

Sign and Verify JWT Access Tokens in Express Auth Middleware

express jwt authentication
by codesnips 3 tabs