Security Protection

Next.js Admin Middleware: JWT Route Guard Practice in Cloudflare Workers Edge Runtime

NestJS Sensitive Word Filtering: AC Automaton Pipe Implementation and Performance Optimization

The blog system's comment content uses the AC Automaton algorithm for sensitive word detection, integrated transparently as a NestJS Pipe. It covers a three-level sensitive word grading strategy, detection performance of < 1ms for a 100,000-word dictionary, a Redis hot-update mechanism, and a multi-layered defense design.

NestJS reCAPTCHA v3 Integration in Practice: Unnoticeable Human Verification, Blocking Script Bots from Scratch

The comment interface of the blog system is under attack from script bots. By integrating Google reCAPTCHA v3, we achieve unnoticeable human verification. This covers the complete implementation of RecaptchaService, a four-tier score processing strategy, Guard integration, and frontend token acquisition.

NestJS Like Deduplication: Fingerprint + Redis Guard Pattern with Distributed Lock

The like endpoint of the blog system implements an anti-spam mechanism using the Fingerprint + Redis Guard pattern. This covers the fingerprint formula (MD5 hash), SET NX atomic operation, 24-hour expiration strategy, and a graceful degradation plan when Redis is unavailable.

NestJS JWT + RBAC Permission System in Practice: From Open APIs to Fine-Grained Access Control

The blog system's management interfaces have evolved from a completely open state to a two-tier protection system of JWT authentication + RBAC permissions, covering the complete implementation of AdminJwtAuthGuard, PermissionsGuard, @RequirePermission decorator, and RolePermissions configuration.

NestJS Device Fingerprint Risk Control System: Redis Blacklist, Multi-Account Detection, and 24h Withdrawal Cooldown

An in-depth analysis of a production-grade NestJS device security service, covering the complete implementation of Redis dual-cache strategy, multi-account detection, automatic banning, and withdrawal cooldown.

Full-Stack KYC Identity Verification System: AWS Rekognition Face Liveness + NestJS Backend + Admin Review

AI Comment Moderation: Zero-Cost Automatic Content Filtering with Gemini 2.0 Flash

A blog system integrates Google Gemini 2.0 Flash (permanently free) to achieve AI-powered automatic comment moderation. Covers a three-tier review mechanism, asynchronous BullMQ queue processing, automatic reply prompt design, and non-blocking architecture design points.