[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"skill:01M6AEDC7FXZN6VBWRD2XJZZ93":3,"skill-same:01M6AEDC7FXZN6VBWRD2XJZZ93":83},{"skillNo":4,"name":5,"nameZh":6,"description":7,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":16,"categories":17,"keywords":29,"publishedAt":51,"linkOnly":52,"markdownContent":53,"markdownBody":54,"frontMatter":55,"refName":59,"commitSha":60,"skillDirectory":61,"forksCount":62,"repositoryHtmlUrl":63,"repositoryHomepageUrl":64,"ownerHtmlUrl":65,"ownerBlogUrl":66,"ownerDescription":67,"updatedAt":68,"install":69,"resources":82},"01M6AEDC7FXZN6VBWRD2XJZZ93","cc-skill-backend-patterns",null,"Backend architecture patterns, API design, database optimization, and server-side best practices for Node.js, Express, and Next.js API routes.","davila7\u002Fclaude-code-templates","davila7","https:\u002F\u002Favatars.githubusercontent.com\u002Fu\u002F6216945?v=4","01M6ADEWWFPS191NFM0Y1EX1JH","Daniel Avila","01M6ADJHGM78PHQRD3XZTFDVKK",33481,"MIT","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fdevelopment\u002Fcc-skill-backend-patterns\u002FSKILL.md",[18,23,26],{"categoryNo":19,"categoryName":20,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000010","后端与接口","SCENARIO","使用场景",{"categoryNo":24,"categoryName":25,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000015","视觉设计",{"categoryNo":27,"categoryName":28,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000023","Skill与智能体开发",[30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50],"patterns","cc","cc skill backend patterns","backend","backend patterns","Next.js","for","server-side","express","next","database optimization","node","design","api","architecture patterns","Optimization","server","database","best practices","api design","architecture","2026-11-10 10:12:30",false,"---\nname: cc-skill-backend-patterns\ndescription: Backend architecture patterns, API design, database optimization, and server-side best practices for Node.js, Express, and Next.js API routes.\nmetadata:\n  author: affaan-m\n  version: \"1.0\"\n---\n\n# Backend Development Patterns\n\nBackend architecture patterns and best practices for scalable server-side applications.\n\n## API Design Patterns\n\n### RESTful API Structure\n\n```typescript\n\u002F\u002F ✅ Resource-based URLs\nGET    \u002Fapi\u002Fmarkets                 # List resources\nGET    \u002Fapi\u002Fmarkets\u002F:id             # Get single resource\nPOST   \u002Fapi\u002Fmarkets                 # Create resource\nPUT    \u002Fapi\u002Fmarkets\u002F:id             # Replace resource\nPATCH  \u002Fapi\u002Fmarkets\u002F:id             # Update resource\nDELETE \u002Fapi\u002Fmarkets\u002F:id             # Delete resource\n\n\u002F\u002F ✅ Query parameters for filtering, sorting, pagination\nGET \u002Fapi\u002Fmarkets?status=active&sort=volume&limit=20&offset=0\n```\n\n### Repository Pattern\n\n```typescript\n\u002F\u002F Abstract data access logic\ninterface MarketRepository {\n  findAll(filters?: MarketFilters): Promise\u003CMarket[]>\n  findById(id: string): Promise\u003CMarket | null>\n  create(data: CreateMarketDto): Promise\u003CMarket>\n  update(id: string, data: UpdateMarketDto): Promise\u003CMarket>\n  delete(id: string): Promise\u003Cvoid>\n}\n\nclass SupabaseMarketRepository implements MarketRepository {\n  async findAll(filters?: MarketFilters): Promise\u003CMarket[]> {\n    let query = supabase.from('markets').select('*')\n\n    if (filters?.status) {\n      query = query.eq('status', filters.status)\n    }\n\n    if (filters?.limit) {\n      query = query.limit(filters.limit)\n    }\n\n    const { data, error } = await query\n\n    if (error) throw new Error(error.message)\n    return data\n  }\n\n  \u002F\u002F Other methods...\n}\n```\n\n### Service Layer Pattern\n\n```typescript\n\u002F\u002F Business logic separated from data access\nclass MarketService {\n  constructor(private marketRepo: MarketRepository) {}\n\n  async searchMarkets(query: string, limit: number = 10): Promise\u003CMarket[]> {\n    \u002F\u002F Business logic\n    const embedding = await generateEmbedding(query)\n    const results = await this.vectorSearch(embedding, limit)\n\n    \u002F\u002F Fetch full data\n    const markets = await this.marketRepo.findByIds(results.map(r => r.id))\n\n    \u002F\u002F Sort by similarity\n    return markets.sort((a, b) => {\n      const scoreA = results.find(r => r.id === a.id)?.score || 0\n      const scoreB = results.find(r => r.id === b.id)?.score || 0\n      return scoreA - scoreB\n    })\n  }\n\n  private async vectorSearch(embedding: number[], limit: number) {\n    \u002F\u002F Vector search implementation\n  }\n}\n```\n\n### Middleware Pattern\n\n```typescript\n\u002F\u002F Request\u002Fresponse processing pipeline\nexport function withAuth(handler: NextApiHandler): NextApiHandler {\n  return async (req, res) => {\n    const token = req.headers.authorization?.replace('Bearer ', '')\n\n    if (!token) {\n      return res.status(401).json({ error: 'Unauthorized' })\n    }\n\n    try {\n      const user = await verifyToken(token)\n      req.user = user\n      return handler(req, res)\n    } catch (error) {\n      return res.status(401).json({ error: 'Invalid token' })\n    }\n  }\n}\n\n\u002F\u002F Usage\nexport default withAuth(async (req, res) => {\n  \u002F\u002F Handler has access to req.user\n})\n```\n\n## Database Patterns\n\n### Query Optimization\n\n```typescript\n\u002F\u002F ✅ GOOD: Select only needed columns\nconst { data } = await supabase\n  .from('markets')\n  .select('id, name, status, volume')\n  .eq('status', 'active')\n  .order('volume', { ascending: false })\n  .limit(10)\n\n\u002F\u002F ❌ BAD: Select everything\nconst { data } = await supabase\n  .from('markets')\n  .select('*')\n```\n\n### N+1 Query Prevention\n\n```typescript\n\u002F\u002F ❌ BAD: N+1 query problem\nconst markets = await getMarkets()\nfor (const market of markets) {\n  market.creator = await getUser(market.creator_id)  \u002F\u002F N queries\n}\n\n\u002F\u002F ✅ GOOD: Batch fetch\nconst markets = await getMarkets()\nconst creatorIds = markets.map(m => m.creator_id)\nconst creators = await getUsers(creatorIds)  \u002F\u002F 1 query\nconst creatorMap = new Map(creators.map(c => [c.id, c]))\n\nmarkets.forEach(market => {\n  market.creator = creatorMap.get(market.creator_id)\n})\n```\n\n### Transaction Pattern\n\n```typescript\nasync function createMarketWithPosition(\n  marketData: CreateMarketDto,\n  positionData: CreatePositionDto\n) {\n  \u002F\u002F Use Supabase transaction\n  const { data, error } = await supabase.rpc('create_market_with_position', {\n    market_data: marketData,\n    position_data: positionData\n  })\n\n  if (error) throw new Error('Transaction failed')\n  return data\n}\n\n\u002F\u002F SQL function in Supabase\nCREATE OR REPLACE FUNCTION create_market_with_position(\n  market_data jsonb,\n  position_data jsonb\n)\nRETURNS jsonb\nLANGUAGE plpgsql\nAS $$\nBEGIN\n  -- Start transaction automatically\n  INSERT INTO markets VALUES (market_data);\n  INSERT INTO positions VALUES (position_data);\n  RETURN jsonb_build_object('success', true);\nEXCEPTION\n  WHEN OTHERS THEN\n    -- Rollback happens automatically\n    RETURN jsonb_build_object('success', false, 'error', SQLERRM);\nEND;\n$$;\n```\n\n## Caching Strategies\n\n### Redis Caching Layer\n\n```typescript\nclass CachedMarketRepository implements MarketRepository {\n  constructor(\n    private baseRepo: MarketRepository,\n    private redis: RedisClient\n  ) {}\n\n  async findById(id: string): Promise\u003CMarket | null> {\n    \u002F\u002F Check cache first\n    const cached = await this.redis.get(`market:${id}`)\n\n    if (cached) {\n      return JSON.parse(cached)\n    }\n\n    \u002F\u002F Cache miss - fetch from database\n    const market = await this.baseRepo.findById(id)\n\n    if (market) {\n      \u002F\u002F Cache for 5 minutes\n      await this.redis.setex(`market:${id}`, 300, JSON.stringify(market))\n    }\n\n    return market\n  }\n\n  async invalidateCache(id: string): Promise\u003Cvoid> {\n    await this.redis.del(`market:${id}`)\n  }\n}\n```\n\n### Cache-Aside Pattern\n\n```typescript\nasync function getMarketWithCache(id: string): Promise\u003CMarket> {\n  const cacheKey = `market:${id}`\n\n  \u002F\u002F Try cache\n  const cached = await redis.get(cacheKey)\n  if (cached) return JSON.parse(cached)\n\n  \u002F\u002F Cache miss - fetch from DB\n  const market = await db.markets.findUnique({ where: { id } })\n\n  if (!market) throw new Error('Market not found')\n\n  \u002F\u002F Update cache\n  await redis.setex(cacheKey, 300, JSON.stringify(market))\n\n  return market\n}\n```\n\n## Error Handling Patterns\n\n### Centralized Error Handler\n\n```typescript\nclass ApiError extends Error {\n  constructor(\n    public statusCode: number,\n    public message: string,\n    public isOperational = true\n  ) {\n    super(message)\n    Object.setPrototypeOf(this, ApiError.prototype)\n  }\n}\n\nexport function errorHandler(error: unknown, req: Request): Response {\n  if (error instanceof ApiError) {\n    return NextResponse.json({\n      success: false,\n      error: error.message\n    }, { status: error.statusCode })\n  }\n\n  if (error instanceof z.ZodError) {\n    return NextResponse.json({\n      success: false,\n      error: 'Validation failed',\n      details: error.errors\n    }, { status: 400 })\n  }\n\n  \u002F\u002F Log unexpected errors\n  console.error('Unexpected error:', error)\n\n  return NextResponse.json({\n    success: false,\n    error: 'Internal server error'\n  }, { status: 500 })\n}\n\n\u002F\u002F Usage\nexport async function GET(request: Request) {\n  try {\n    const data = await fetchData()\n    return NextResponse.json({ success: true, data })\n  } catch (error) {\n    return errorHandler(error, request)\n  }\n}\n```\n\n### Retry with Exponential Backoff\n\n```typescript\nasync function fetchWithRetry\u003CT>(\n  fn: () => Promise\u003CT>,\n  maxRetries = 3\n): Promise\u003CT> {\n  let lastError: Error\n\n  for (let i = 0; i \u003C maxRetries; i++) {\n    try {\n      return await fn()\n    } catch (error) {\n      lastError = error as Error\n\n      if (i \u003C maxRetries - 1) {\n        \u002F\u002F Exponential backoff: 1s, 2s, 4s\n        const delay = Math.pow(2, i) * 1000\n        await new Promise(resolve => setTimeout(resolve, delay))\n      }\n    }\n  }\n\n  throw lastError!\n}\n\n\u002F\u002F Usage\nconst data = await fetchWithRetry(() => fetchFromAPI())\n```\n\n## Authentication & Authorization\n\n### JWT Token Validation\n\n```typescript\nimport jwt from 'jsonwebtoken'\n\ninterface JWTPayload {\n  userId: string\n  email: string\n  role: 'admin' | 'user'\n}\n\nexport function verifyToken(token: string): JWTPayload {\n  try {\n    const payload = jwt.verify(token, process.env.JWT_SECRET!) as JWTPayload\n    return payload\n  } catch (error) {\n    throw new ApiError(401, 'Invalid token')\n  }\n}\n\nexport async function requireAuth(request: Request) {\n  const token = request.headers.get('authorization')?.replace('Bearer ', '')\n\n  if (!token) {\n    throw new ApiError(401, 'Missing authorization token')\n  }\n\n  return verifyToken(token)\n}\n\n\u002F\u002F Usage in API route\nexport async function GET(request: Request) {\n  const user = await requireAuth(request)\n\n  const data = await getDataForUser(user.userId)\n\n  return NextResponse.json({ success: true, data })\n}\n```\n\n### Role-Based Access Control\n\n```typescript\ntype Permission = 'read' | 'write' | 'delete' | 'admin'\n\ninterface User {\n  id: string\n  role: 'admin' | 'moderator' | 'user'\n}\n\nconst rolePermissions: Record\u003CUser['role'], Permission[]> = {\n  admin: ['read', 'write', 'delete', 'admin'],\n  moderator: ['read', 'write', 'delete'],\n  user: ['read', 'write']\n}\n\nexport function hasPermission(user: User, permission: Permission): boolean {\n  return rolePermissions[user.role].includes(permission)\n}\n\nexport function requirePermission(permission: Permission) {\n  return async (request: Request) => {\n    const user = await requireAuth(request)\n\n    if (!hasPermission(user, permission)) {\n      throw new ApiError(403, 'Insufficient permissions')\n    }\n\n    return user\n  }\n}\n\n\u002F\u002F Usage\nexport const DELETE = requirePermission('delete')(async (request: Request) => {\n  \u002F\u002F Handler with permission check\n})\n```\n\n## Rate Limiting\n\n### Simple In-Memory Rate Limiter\n\n```typescript\nclass RateLimiter {\n  private requests = new Map\u003Cstring, number[]>()\n\n  async checkLimit(\n    identifier: string,\n    maxRequests: number,\n    windowMs: number\n  ): Promise\u003Cboolean> {\n    const now = Date.now()\n    const requests = this.requests.get(identifier) || []\n\n    \u002F\u002F Remove old requests outside window\n    const recentRequests = requests.filter(time => now - time \u003C windowMs)\n\n    if (recentRequests.length >= maxRequests) {\n      return false  \u002F\u002F Rate limit exceeded\n    }\n\n    \u002F\u002F Add current request\n    recentRequests.push(now)\n    this.requests.set(identifier, recentRequests)\n\n    return true\n  }\n}\n\nconst limiter = new RateLimiter()\n\nexport async function GET(request: Request) {\n  const ip = request.headers.get('x-forwarded-for') || 'unknown'\n\n  const allowed = await limiter.checkLimit(ip, 100, 60000)  \u002F\u002F 100 req\u002Fmin\n\n  if (!allowed) {\n    return NextResponse.json({\n      error: 'Rate limit exceeded'\n    }, { status: 429 })\n  }\n\n  \u002F\u002F Continue with request\n}\n```\n\n## Background Jobs & Queues\n\n### Simple Queue Pattern\n\n```typescript\nclass JobQueue\u003CT> {\n  private queue: T[] = []\n  private processing = false\n\n  async add(job: T): Promise\u003Cvoid> {\n    this.queue.push(job)\n\n    if (!this.processing) {\n      this.process()\n    }\n  }\n\n  private async process(): Promise\u003Cvoid> {\n    this.processing = true\n\n    while (this.queue.length > 0) {\n      const job = this.queue.shift()!\n\n      try {\n        await this.execute(job)\n      } catch (error) {\n        console.error('Job failed:', error)\n      }\n    }\n\n    this.processing = false\n  }\n\n  private async execute(job: T): Promise\u003Cvoid> {\n    \u002F\u002F Job execution logic\n  }\n}\n\n\u002F\u002F Usage for indexing markets\ninterface IndexJob {\n  marketId: string\n}\n\nconst indexQueue = new JobQueue\u003CIndexJob>()\n\nexport async function POST(request: Request) {\n  const { marketId } = await request.json()\n\n  \u002F\u002F Add to queue instead of blocking\n  await indexQueue.add({ marketId })\n\n  return NextResponse.json({ success: true, message: 'Job queued' })\n}\n```\n\n## Logging & Monitoring\n\n### Structured Logging\n\n```typescript\ninterface LogContext {\n  userId?: string\n  requestId?: string\n  method?: string\n  path?: string\n  [key: string]: unknown\n}\n\nclass Logger {\n  log(level: 'info' | 'warn' | 'error', message: string, context?: LogContext) {\n    const entry = {\n      timestamp: new Date().toISOString(),\n      level,\n      message,\n      ...context\n    }\n\n    console.log(JSON.stringify(entry))\n  }\n\n  info(message: string, context?: LogContext) {\n    this.log('info', message, context)\n  }\n\n  warn(message: string, context?: LogContext) {\n    this.log('warn', message, context)\n  }\n\n  error(message: string, error: Error, context?: LogContext) {\n    this.log('error', message, {\n      ...context,\n      error: error.message,\n      stack: error.stack\n    })\n  }\n}\n\nconst logger = new Logger()\n\n\u002F\u002F Usage\nexport async function GET(request: Request) {\n  const requestId = crypto.randomUUID()\n\n  logger.info('Fetching markets', {\n    requestId,\n    method: 'GET',\n    path: '\u002Fapi\u002Fmarkets'\n  })\n\n  try {\n    const markets = await fetchMarkets()\n    return NextResponse.json({ success: true, data: markets })\n  } catch (error) {\n    logger.error('Failed to fetch markets', error as Error, { requestId })\n    return NextResponse.json({ error: 'Internal error' }, { status: 500 })\n  }\n}\n```\n\n**Remember**: Backend patterns enable scalable, maintainable server-side applications. Choose patterns that fit your complexity level.","# Backend Development Patterns\n\nBackend architecture patterns and best practices for scalable server-side applications.\n\n## API Design Patterns\n\n### RESTful API Structure\n\n```typescript\n\u002F\u002F ✅ Resource-based URLs\nGET    \u002Fapi\u002Fmarkets                 # List resources\nGET    \u002Fapi\u002Fmarkets\u002F:id             # Get single resource\nPOST   \u002Fapi\u002Fmarkets                 # Create resource\nPUT    \u002Fapi\u002Fmarkets\u002F:id             # Replace resource\nPATCH  \u002Fapi\u002Fmarkets\u002F:id             # Update resource\nDELETE \u002Fapi\u002Fmarkets\u002F:id             # Delete resource\n\n\u002F\u002F ✅ Query parameters for filtering, sorting, pagination\nGET \u002Fapi\u002Fmarkets?status=active&sort=volume&limit=20&offset=0\n```\n\n### Repository Pattern\n\n```typescript\n\u002F\u002F Abstract data access logic\ninterface MarketRepository {\n  findAll(filters?: MarketFilters): Promise\u003CMarket[]>\n  findById(id: string): Promise\u003CMarket | null>\n  create(data: CreateMarketDto): Promise\u003CMarket>\n  update(id: string, data: UpdateMarketDto): Promise\u003CMarket>\n  delete(id: string): Promise\u003Cvoid>\n}\n\nclass SupabaseMarketRepository implements MarketRepository {\n  async findAll(filters?: MarketFilters): Promise\u003CMarket[]> {\n    let query = supabase.from('markets').select('*')\n\n    if (filters?.status) {\n      query = query.eq('status', filters.status)\n    }\n\n    if (filters?.limit) {\n      query = query.limit(filters.limit)\n    }\n\n    const { data, error } = await query\n\n    if (error) throw new Error(error.message)\n    return data\n  }\n\n  \u002F\u002F Other methods...\n}\n```\n\n### Service Layer Pattern\n\n```typescript\n\u002F\u002F Business logic separated from data access\nclass MarketService {\n  constructor(private marketRepo: MarketRepository) {}\n\n  async searchMarkets(query: string, limit: number = 10): Promise\u003CMarket[]> {\n    \u002F\u002F Business logic\n    const embedding = await generateEmbedding(query)\n    const results = await this.vectorSearch(embedding, limit)\n\n    \u002F\u002F Fetch full data\n    const markets = await this.marketRepo.findByIds(results.map(r => r.id))\n\n    \u002F\u002F Sort by similarity\n    return markets.sort((a, b) => {\n      const scoreA = results.find(r => r.id === a.id)?.score || 0\n      const scoreB = results.find(r => r.id === b.id)?.score || 0\n      return scoreA - scoreB\n    })\n  }\n\n  private async vectorSearch(embedding: number[], limit: number) {\n    \u002F\u002F Vector search implementation\n  }\n}\n```\n\n### Middleware Pattern\n\n```typescript\n\u002F\u002F Request\u002Fresponse processing pipeline\nexport function withAuth(handler: NextApiHandler): NextApiHandler {\n  return async (req, res) => {\n    const token = req.headers.authorization?.replace('Bearer ', '')\n\n    if (!token) {\n      return res.status(401).json({ error: 'Unauthorized' })\n    }\n\n    try {\n      const user = await verifyToken(token)\n      req.user = user\n      return handler(req, res)\n    } catch (error) {\n      return res.status(401).json({ error: 'Invalid token' })\n    }\n  }\n}\n\n\u002F\u002F Usage\nexport default withAuth(async (req, res) => {\n  \u002F\u002F Handler has access to req.user\n})\n```\n\n## Database Patterns\n\n### Query Optimization\n\n```typescript\n\u002F\u002F ✅ GOOD: Select only needed columns\nconst { data } = await supabase\n  .from('markets')\n  .select('id, name, status, volume')\n  .eq('status', 'active')\n  .order('volume', { ascending: false })\n  .limit(10)\n\n\u002F\u002F ❌ BAD: Select everything\nconst { data } = await supabase\n  .from('markets')\n  .select('*')\n```\n\n### N+1 Query Prevention\n\n```typescript\n\u002F\u002F ❌ BAD: N+1 query problem\nconst markets = await getMarkets()\nfor (const market of markets) {\n  market.creator = await getUser(market.creator_id)  \u002F\u002F N queries\n}\n\n\u002F\u002F ✅ GOOD: Batch fetch\nconst markets = await getMarkets()\nconst creatorIds = markets.map(m => m.creator_id)\nconst creators = await getUsers(creatorIds)  \u002F\u002F 1 query\nconst creatorMap = new Map(creators.map(c => [c.id, c]))\n\nmarkets.forEach(market => {\n  market.creator = creatorMap.get(market.creator_id)\n})\n```\n\n### Transaction Pattern\n\n```typescript\nasync function createMarketWithPosition(\n  marketData: CreateMarketDto,\n  positionData: CreatePositionDto\n) {\n  \u002F\u002F Use Supabase transaction\n  const { data, error } = await supabase.rpc('create_market_with_position', {\n    market_data: marketData,\n    position_data: positionData\n  })\n\n  if (error) throw new Error('Transaction failed')\n  return data\n}\n\n\u002F\u002F SQL function in Supabase\nCREATE OR REPLACE FUNCTION create_market_with_position(\n  market_data jsonb,\n  position_data jsonb\n)\nRETURNS jsonb\nLANGUAGE plpgsql\nAS $$\nBEGIN\n  -- Start transaction automatically\n  INSERT INTO markets VALUES (market_data);\n  INSERT INTO positions VALUES (position_data);\n  RETURN jsonb_build_object('success', true);\nEXCEPTION\n  WHEN OTHERS THEN\n    -- Rollback happens automatically\n    RETURN jsonb_build_object('success', false, 'error', SQLERRM);\nEND;\n$$;\n```\n\n## Caching Strategies\n\n### Redis Caching Layer\n\n```typescript\nclass CachedMarketRepository implements MarketRepository {\n  constructor(\n    private baseRepo: MarketRepository,\n    private redis: RedisClient\n  ) {}\n\n  async findById(id: string): Promise\u003CMarket | null> {\n    \u002F\u002F Check cache first\n    const cached = await this.redis.get(`market:${id}`)\n\n    if (cached) {\n      return JSON.parse(cached)\n    }\n\n    \u002F\u002F Cache miss - fetch from database\n    const market = await this.baseRepo.findById(id)\n\n    if (market) {\n      \u002F\u002F Cache for 5 minutes\n      await this.redis.setex(`market:${id}`, 300, JSON.stringify(market))\n    }\n\n    return market\n  }\n\n  async invalidateCache(id: string): Promise\u003Cvoid> {\n    await this.redis.del(`market:${id}`)\n  }\n}\n```\n\n### Cache-Aside Pattern\n\n```typescript\nasync function getMarketWithCache(id: string): Promise\u003CMarket> {\n  const cacheKey = `market:${id}`\n\n  \u002F\u002F Try cache\n  const cached = await redis.get(cacheKey)\n  if (cached) return JSON.parse(cached)\n\n  \u002F\u002F Cache miss - fetch from DB\n  const market = await db.markets.findUnique({ where: { id } })\n\n  if (!market) throw new Error('Market not found')\n\n  \u002F\u002F Update cache\n  await redis.setex(cacheKey, 300, JSON.stringify(market))\n\n  return market\n}\n```\n\n## Error Handling Patterns\n\n### Centralized Error Handler\n\n```typescript\nclass ApiError extends Error {\n  constructor(\n    public statusCode: number,\n    public message: string,\n    public isOperational = true\n  ) {\n    super(message)\n    Object.setPrototypeOf(this, ApiError.prototype)\n  }\n}\n\nexport function errorHandler(error: unknown, req: Request): Response {\n  if (error instanceof ApiError) {\n    return NextResponse.json({\n      success: false,\n      error: error.message\n    }, { status: error.statusCode })\n  }\n\n  if (error instanceof z.ZodError) {\n    return NextResponse.json({\n      success: false,\n      error: 'Validation failed',\n      details: error.errors\n    }, { status: 400 })\n  }\n\n  \u002F\u002F Log unexpected errors\n  console.error('Unexpected error:', error)\n\n  return NextResponse.json({\n    success: false,\n    error: 'Internal server error'\n  }, { status: 500 })\n}\n\n\u002F\u002F Usage\nexport async function GET(request: Request) {\n  try {\n    const data = await fetchData()\n    return NextResponse.json({ success: true, data })\n  } catch (error) {\n    return errorHandler(error, request)\n  }\n}\n```\n\n### Retry with Exponential Backoff\n\n```typescript\nasync function fetchWithRetry\u003CT>(\n  fn: () => Promise\u003CT>,\n  maxRetries = 3\n): Promise\u003CT> {\n  let lastError: Error\n\n  for (let i = 0; i \u003C maxRetries; i++) {\n    try {\n      return await fn()\n    } catch (error) {\n      lastError = error as Error\n\n      if (i \u003C maxRetries - 1) {\n        \u002F\u002F Exponential backoff: 1s, 2s, 4s\n        const delay = Math.pow(2, i) * 1000\n        await new Promise(resolve => setTimeout(resolve, delay))\n      }\n    }\n  }\n\n  throw lastError!\n}\n\n\u002F\u002F Usage\nconst data = await fetchWithRetry(() => fetchFromAPI())\n```\n\n## Authentication & Authorization\n\n### JWT Token Validation\n\n```typescript\nimport jwt from 'jsonwebtoken'\n\ninterface JWTPayload {\n  userId: string\n  email: string\n  role: 'admin' | 'user'\n}\n\nexport function verifyToken(token: string): JWTPayload {\n  try {\n    const payload = jwt.verify(token, process.env.JWT_SECRET!) as JWTPayload\n    return payload\n  } catch (error) {\n    throw new ApiError(401, 'Invalid token')\n  }\n}\n\nexport async function requireAuth(request: Request) {\n  const token = request.headers.get('authorization')?.replace('Bearer ', '')\n\n  if (!token) {\n    throw new ApiError(401, 'Missing authorization token')\n  }\n\n  return verifyToken(token)\n}\n\n\u002F\u002F Usage in API route\nexport async function GET(request: Request) {\n  const user = await requireAuth(request)\n\n  const data = await getDataForUser(user.userId)\n\n  return NextResponse.json({ success: true, data })\n}\n```\n\n### Role-Based Access Control\n\n```typescript\ntype Permission = 'read' | 'write' | 'delete' | 'admin'\n\ninterface User {\n  id: string\n  role: 'admin' | 'moderator' | 'user'\n}\n\nconst rolePermissions: Record\u003CUser['role'], Permission[]> = {\n  admin: ['read', 'write', 'delete', 'admin'],\n  moderator: ['read', 'write', 'delete'],\n  user: ['read', 'write']\n}\n\nexport function hasPermission(user: User, permission: Permission): boolean {\n  return rolePermissions[user.role].includes(permission)\n}\n\nexport function requirePermission(permission: Permission) {\n  return async (request: Request) => {\n    const user = await requireAuth(request)\n\n    if (!hasPermission(user, permission)) {\n      throw new ApiError(403, 'Insufficient permissions')\n    }\n\n    return user\n  }\n}\n\n\u002F\u002F Usage\nexport const DELETE = requirePermission('delete')(async (request: Request) => {\n  \u002F\u002F Handler with permission check\n})\n```\n\n## Rate Limiting\n\n### Simple In-Memory Rate Limiter\n\n```typescript\nclass RateLimiter {\n  private requests = new Map\u003Cstring, number[]>()\n\n  async checkLimit(\n    identifier: string,\n    maxRequests: number,\n    windowMs: number\n  ): Promise\u003Cboolean> {\n    const now = Date.now()\n    const requests = this.requests.get(identifier) || []\n\n    \u002F\u002F Remove old requests outside window\n    const recentRequests = requests.filter(time => now - time \u003C windowMs)\n\n    if (recentRequests.length >= maxRequests) {\n      return false  \u002F\u002F Rate limit exceeded\n    }\n\n    \u002F\u002F Add current request\n    recentRequests.push(now)\n    this.requests.set(identifier, recentRequests)\n\n    return true\n  }\n}\n\nconst limiter = new RateLimiter()\n\nexport async function GET(request: Request) {\n  const ip = request.headers.get('x-forwarded-for') || 'unknown'\n\n  const allowed = await limiter.checkLimit(ip, 100, 60000)  \u002F\u002F 100 req\u002Fmin\n\n  if (!allowed) {\n    return NextResponse.json({\n      error: 'Rate limit exceeded'\n    }, { status: 429 })\n  }\n\n  \u002F\u002F Continue with request\n}\n```\n\n## Background Jobs & Queues\n\n### Simple Queue Pattern\n\n```typescript\nclass JobQueue\u003CT> {\n  private queue: T[] = []\n  private processing = false\n\n  async add(job: T): Promise\u003Cvoid> {\n    this.queue.push(job)\n\n    if (!this.processing) {\n      this.process()\n    }\n  }\n\n  private async process(): Promise\u003Cvoid> {\n    this.processing = true\n\n    while (this.queue.length > 0) {\n      const job = this.queue.shift()!\n\n      try {\n        await this.execute(job)\n      } catch (error) {\n        console.error('Job failed:', error)\n      }\n    }\n\n    this.processing = false\n  }\n\n  private async execute(job: T): Promise\u003Cvoid> {\n    \u002F\u002F Job execution logic\n  }\n}\n\n\u002F\u002F Usage for indexing markets\ninterface IndexJob {\n  marketId: string\n}\n\nconst indexQueue = new JobQueue\u003CIndexJob>()\n\nexport async function POST(request: Request) {\n  const { marketId } = await request.json()\n\n  \u002F\u002F Add to queue instead of blocking\n  await indexQueue.add({ marketId })\n\n  return NextResponse.json({ success: true, message: 'Job queued' })\n}\n```\n\n## Logging & Monitoring\n\n### Structured Logging\n\n```typescript\ninterface LogContext {\n  userId?: string\n  requestId?: string\n  method?: string\n  path?: string\n  [key: string]: unknown\n}\n\nclass Logger {\n  log(level: 'info' | 'warn' | 'error', message: string, context?: LogContext) {\n    const entry = {\n      timestamp: new Date().toISOString(),\n      level,\n      message,\n      ...context\n    }\n\n    console.log(JSON.stringify(entry))\n  }\n\n  info(message: string, context?: LogContext) {\n    this.log('info', message, context)\n  }\n\n  warn(message: string, context?: LogContext) {\n    this.log('warn', message, context)\n  }\n\n  error(message: string, error: Error, context?: LogContext) {\n    this.log('error', message, {\n      ...context,\n      error: error.message,\n      stack: error.stack\n    })\n  }\n}\n\nconst logger = new Logger()\n\n\u002F\u002F Usage\nexport async function GET(request: Request) {\n  const requestId = crypto.randomUUID()\n\n  logger.info('Fetching markets', {\n    requestId,\n    method: 'GET',\n    path: '\u002Fapi\u002Fmarkets'\n  })\n\n  try {\n    const markets = await fetchMarkets()\n    return NextResponse.json({ success: true, data: markets })\n  } catch (error) {\n    logger.error('Failed to fetch markets', error as Error, { requestId })\n    return NextResponse.json({ error: 'Internal error' }, { status: 500 })\n  }\n}\n```\n\n**Remember**: Backend patterns enable scalable, maintainable server-side applications. Choose patterns that fit your complexity level.",{"name":5,"metadata":56,"description":7},{"author":57,"version":58},"affaan-m","1.0","main","2b749c82b5d11fac39d9a6e021ce3f5b8a541bd1","cli-tool\u002Fcomponents\u002Fskills\u002Fdevelopment\u002Fcc-skill-backend-patterns",3931,"https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates","https:\u002F\u002Faitmpl.com","https:\u002F\u002Fgithub.com\u002Fdavila7","https:\u002F\u002Fdanielavila.me","Building AI dev tools with LLMs","2026-11-14 06:14:46",{"source":8,"skillName":5,"commands":70,"prompt":80,"zipAvailable":81},[71,74,77],{"tool":72,"command":73},"npx","npx skills add davila7\u002Fclaude-code-templates --skill cc-skill-backend-patterns",{"tool":75,"command":76},"bunx","bunx skills add davila7\u002Fclaude-code-templates --skill cc-skill-backend-patterns",{"tool":78,"command":79},"pnpm","pnpm dlx skills add davila7\u002Fclaude-code-templates --skill cc-skill-backend-patterns","安装技能，技能地址：https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fdevelopment\u002Fcc-skill-backend-patterns\u002FSKILL.md",true,[],[84,111,138,168,203,227],{"skillNo":85,"name":86,"nameZh":6,"description":87,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":88,"categories":89,"keywords":91,"publishedAt":51},"01M70NHBTQ8BV0A2SCAZXEPHCX","wealthville-pool-scoring","Score DeFi liquidity pools before providing liquidity. Returns a 0-100 pool score and an Enter\u002FHold\u002FExit\u002FReduce\u002FAvoid verdict with calibrated confidence for ~68,800 Solana pools and 575 EVM pools, plus a public miss-inclusive track record. Use when asked whether a pool is worth LPing into, which pools look best right now, or how accurate the scores have actually been.","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fweb-data\u002Fwealthville-pool-scoring\u002FSKILL.md",[90],{"categoryNo":27,"categoryName":28,"taxonomyType":21,"taxonomyTypeDesc":22},[92,93,94,95,96,36,97,98,99,100,101,102,103,104,105,106,107,108,109,110],"scoring","pool","wealthville pool scoring","liquidity","which","exit","now","use","when","reduce","with","record","track","verdict","evm","solana","how","public","look",{"skillNo":112,"name":113,"nameZh":6,"description":114,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":115,"categories":116,"keywords":118,"publishedAt":51},"01M70MB6VR8ERJ4EM8D5KHBMEV","technical-debt-auditor","Scans a codebase and produces a quantified technical debt report with a prioritized remediation plan. Analyzes dead code, TODO\u002FFIXME\u002FHACK markers, dependency staleness, complexity hotspots, code duplication signals, test coverage gaps, unused exports, and outdated patterns. Use this skill when the user asks to audit their codebase for tech debt, wants a health check of their code quality, says things like \"where should I focus refactoring\", \"find code smells\", \"audit my codebase\", \"what technical debt do we have\", \"prioritize cleanup work\", or asks about code quality metrics. Also trigger when the user mentions \"code rot\", \"legacy cleanup\", \"refactoring priorities\", or wants to understand the overall health of a project before a major effort. Trigger even if the user doesn't say \"technical debt\" explicitly — any request to systematically assess code quality and identify improvement priorities belongs here.","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fdevelopment\u002Ftechnical-debt-auditor\u002FSKILL.md",[117],{"categoryNo":27,"categoryName":28,"taxonomyType":21,"taxonomyTypeDesc":22},[119,120,121,122,123,124,125,126,127,128,129,100,130,131,132,133,134,135,136,137],"technical debt","debt","technical","technical debt auditor","auditor","coverage","complexity","markers","project","cleanup","unused","code","todo","work","plan","focus","signals","audit","dependency",{"skillNo":139,"name":140,"nameZh":6,"description":141,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":15,"licenseFileUrl":6,"sourceHtmlUrl":142,"categories":143,"keywords":151,"publishedAt":51},"01M70KPYH9QNHCNME5GJQGE22K","readonly-sql-guard","Make an agent's database access provably read-only. Use when an agent runs caller-supplied SQL against a production\u002FERP\u002Fanalytics database (a \"query\" MCP tool, text-to-SQL, an admin console), or when reviewing DB-access code for write\u002FDDL\u002Fside-effect\u002Ftransaction-escape risks. Checks what a statement CALLS, not just its shape.","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fdatabase\u002Freadonly-sql-guard\u002FSKILL.md",[144,145,146],{"categoryNo":19,"categoryName":20,"taxonomyType":21,"taxonomyTypeDesc":22},{"categoryNo":27,"categoryName":28,"taxonomyType":21,"taxonomyTypeDesc":22},{"categoryNo":147,"categoryName":148,"taxonomyType":149,"taxonomyTypeDesc":150},"01JBSEEDCAT000000000000033","数据分析师","PROFESSION","适用职业",[152,153,154,155,156,157,158,36,159,160,161,162,163,164,165,99,166,47,100,167],"readonly","guard","sql guard","sql","readonly sql guard","erp","effect","read-only","db","just","tool","calls","only","MCP","access","query",{"skillNo":169,"name":170,"nameZh":6,"description":171,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":172,"licenseFileUrl":173,"sourceHtmlUrl":174,"categories":175,"keywords":179,"publishedAt":51},"01M6AFY6F7CC2BBZP1QD6VTNVC","web-artifacts-builder","Suite of tools for creating elaborate, multi-component claude.ai HTML artifacts using modern frontend web technologies (React, Tailwind CSS, shadcn\u002Fui). Use for complex artifacts requiring state management, routing, or shadcn\u002Fui components - not for simple single-file HTML\u002FJSX artifacts.","Apache-2.0","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Futilities\u002Fweb-artifacts-builder\u002FLICENSE.txt","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Futilities\u002Fweb-artifacts-builder\u002FSKILL.md",[176],{"categoryNo":177,"categoryName":178,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000009","前端开发",[180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,36,202],"artifacts builder","web","web artifacts builder","artifacts","builder","state","routing","state management","component","css","frontend","ui","Tools","file","components","shadcn","react","Tailwind","suite","jsx","html","single-file","ui components",{"skillNo":204,"name":205,"nameZh":6,"description":206,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":172,"licenseFileUrl":207,"sourceHtmlUrl":208,"categories":209,"keywords":214,"publishedAt":51},"01M6AFWF33SFV9Z3SF4PEEE4BF","webapp-testing","Toolkit for interacting with and testing local web applications using Playwright. Supports verifying frontend functionality, debugging UI behavior, capturing browser screenshots, and viewing browser logs.","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fsecurity\u002Fwebapp-testing\u002FLICENSE.txt","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fsecurity\u002Fwebapp-testing\u002FSKILL.md",[210,213],{"categoryNo":211,"categoryName":212,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000008","测试与质量",{"categoryNo":177,"categoryName":178,"taxonomyType":21,"taxonomyTypeDesc":22},[215,216,217,218,219,181,220,190,191,221,222,223,224,36,225,102,226],"webapp testing","testing","webapp","browser","playwright","applications","debugging","toolkit","logs","screenshots","local","behavior",{"skillNo":228,"name":229,"nameZh":6,"description":230,"descriptionZh":6,"repositoryFullName":8,"ownerLogin":9,"ownerAvatarUrl":10,"ownerAccountNo":11,"ownerDisplayName":12,"repositoryNo":13,"starsCount":14,"licenseSpdxId":172,"licenseFileUrl":231,"sourceHtmlUrl":232,"categories":233,"keywords":241,"publishedAt":51},"01M6AF67Q67JJJ5V51JR2P52KA","discernment-nudge","After you give a substantive answer or draft that the user may act on — advice or recommendations, drafted artifacts such as goals, plans, pitches, proposals, or emails, estimates or projections, analysis or interpretation of data, factual claims they may rely on, or a multi-step argument — invoke this skill BEFORE finalizing your reply and then, if it applies, append 2-3 short follow-up questions, each tied to something specific in what you just produced, that help the user check key facts, probe the reasoning or assumptions, and notice missing context. Do this at most once per conversation. Skip it when the user asked a trivial how-to or simple lookup, wants a purely educational explanation, asked you only to format, convert, or assemble a file from content they provided, is writing code they will run, is doing creative writing or casual chat, or already asked you to double-check, cite, or review — the skill file explains these boundaries and the exact output format.","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fproductivity\u002Fdiscernment-nudge\u002FLICENSE.txt","https:\u002F\u002Fgithub.com\u002Fdavila7\u002Fclaude-code-templates\u002Fblob\u002Fmain\u002Fcli-tool\u002Fcomponents\u002Fskills\u002Fproductivity\u002Fdiscernment-nudge\u002FSKILL.md",[234,237,238],{"categoryNo":235,"categoryName":236,"taxonomyType":21,"taxonomyTypeDesc":22},"01JBSEEDCAT000000000000018","写作与文案",{"categoryNo":27,"categoryName":28,"taxonomyType":21,"taxonomyTypeDesc":22},{"categoryNo":239,"categoryName":240,"taxonomyType":149,"taxonomyTypeDesc":150},"01JBSEEDCAT000000000000036","内容创作者",[242,243,244,245,246,247,248,249,183,250,193,130,251,252,253,254,255,164,256,100,257,258,259,260,261,108,262],"discernment nudge","nudge","interpretation","help","run","reasoning","data","writing","lookup","content","review","conversation","short","up","invoke","you","analysis","claims","argument","assemble","recommendations"]