Daily micro-tips for C#, SQL, performance, and scalable backend engineering.
🧹 using var x = new StreamReader(); Old using needed braces and indentation. Using declarations dispose at end of scope. Less nesting, cleaner code. ❌ Old Using (Nested) using (var file = new StreamReader(“data.txt”)) { using (var writer = new StreamWriter(“output.txt”)) { writer.Write(file.ReadToEnd()); } } ✅ Using Declaration using var file = new StreamReader(“data.txt”); using […]
➕ Add Methods to Interfaces Without Breaking Implementations Adding to interface breaks all implementers. Default interface methods provide implementation. Existing code continues to work. ❌ Before (Breaks) interface ILogger { void Log(string message); // Adding new method breaks all implementers } ✅ Default Method (No Break) interface ILogger { void Log(string message); void LogError(string error) […]
📅 JOIN with Missing Dates? Fill the Gaps Sales report missing dates = misleading. Generate series creates sequences. Fill missing dates with zero sales. 📝 PostgreSQL generate_series — Generate numbers 1 to 100 SELECT generate_series(1, 100); — Generate dates SELECT generate_series( ‘2024-01-01’::date, ‘2024-12-31’::date, ‘1 day’::interval ); — Generate with step SELECT generate_series(0, 100, 10); — […]
🌍 Development, Staging, Production — One Config appsettings.Development.json works. Environment variables override config in production. No code changes. No redeploys. 📝 ASP.NET Core Setup // Program.cs var builder = WebApplication.CreateBuilder(args); // Environment variables override appsettings.json builder.Configuration.AddEnvironmentVariables(); // Or prefix to avoid conflicts builder.Configuration.AddEnvironmentVariables(“MYAPP_”); // Set environment builder.Environment.EnvironmentName = Environment.GetEnvironmentVariable(“ASPNETCORE_ENVIRONMENT”) ?? “Production”; // appsettings.json { “Database”: […]
📦 No Internet? No Problem. Need to share repo offline? Git bundle packs entire repo into a single file. USB transfer, email, any method works. 📝 Create Bundle # Bundle entire repo git bundle create myrepo.bundle –all # Bundle specific branch git bundle create feature.bundle feature-branch # Bundle range of commits git bundle create updates.bundle […]
🔄 Browser Cache Returns Old Data GET requests are cached. Cache-Control headers prevent stale data. Always fresh for dynamic content. 📝 Server Headers # No caching (always fresh) Cache-Control: no-store, no-cache, must-revalidate # Cache for 1 hour Cache-Control: public, max-age=3600 # Cache but revalidate Cache-Control: public, max-age=3600, must-revalidate # Private cache (browser only) Cache-Control: private, […]
🏷️ break only breaks inner loop Need to exit nested loops? Labeled statements break or continue outer loops. Perfect for search in matrix. ❌ Without Label (Cannot break outer) for (let i = 0; i < 10; i++) { for (let j = 0; j < 10; j++) { if (found) { break; // Only […]
⚡ Tell Browser What’s Important Browsers discover resources as they parse HTML. Resource hints tell browser earlier. Faster LCP, better UX. 📝 Preload (Critical Resources) <!– Fonts (discovered late in CSS) –> <link rel=”preload” href=”font.woff2″ as=”font” type=”font/woff2″ crossorigin> <!– Hero image (discovered after CSS) –> <link rel=”preload” href=”hero.jpg” as=”image”> <!– Critical CSS (inline? No, preload) […]
⌨️ Show Focus Only for Keyboard Users Mouse users don’t need focus rings. Keyboard users do. :focus-visible shows focus only when needed. Best of both worlds. ❌ :focus (Always Shows) /* Ugly outline on mouse click */ button:focus { outline: 2px solid blue; } /* Mouse users see blue ring unnecessarily */ ✅ :focus-visible (Smart) […]
⏪ Go Back in Time Installing drivers? Registry edits? System Restore takes snapshot. If something breaks, revert to working state. 🔧 Create Restore Point Method 1: Start → Create a restore point Method 2: Win + R → sysdm.cpl → System Protection To create: 1. Click “Create” 2. Name it (e.g., “Before driver update”) 3. […]
🚀 10 Second Query → 0.1 Second Don’t know SQL optimization? AI analyzes query, suggests indexes, rewrites for speed. Massive performance gains. 📝 The Prompt I have a slow SQL query that needs optimization. Current query: [paste your SQL query] Database: [PostgreSQL/MySQL/SQL Server] Table sizes: – users: 1 million rows – orders: 5 million rows […]
🔄 One CLI, Multiple Docker Daemons Docker CLI talks to local daemon. Docker context switches to remote daemon. Build on local, deploy to remote. No SSH or env vars. 📝 Create and Use Contexts # List contexts docker context ls # Create context for remote Docker (with SSH) docker context create remote –docker host=ssh://user@remote-server # […]
⭐ DNS Pods Should Evict Batch Jobs When cluster is full, which pods get evicted? Priority Classes define importance. Critical pods survive. Batch jobs go first. 📝 Define Priority Classes apiVersion: scheduling.k8s.io/v1 kind: PriorityClass metadata: name: critical value: 1000000000 globalDefault: false description: “Critical system pods that must never be evicted” — apiVersion: scheduling.k8s.io/v1 kind: PriorityClass […]
🏷️ More Than Categories and Tags Posts have categories, tags. Products need brands, sizes, colors. Custom taxonomies create any classification system. 📝 Register Custom Taxonomy // functions.php function create_product_taxonomies() { // Brand taxonomy (hierarchical like categories) register_taxonomy(‘product_brand’, ‘product’, array( ‘labels’ => array( ‘name’ => ‘Brands’, ‘singular_name’ => ‘Brand’, ‘search_items’ => ‘Search Brands’, ‘all_items’ => ‘All […]
✨ Separate Texture from Color Healing Brush blends texture and color. Frequency Separation separates them. Edit color without affecting skin pores. Edit texture without changing color. 📝 Create Frequency Separation 1. Duplicate layer twice (Ctrl+J, Ctrl+J) 2. Name top layer “Texture”, middle “Color”, hide top 3. Select Color layer → Filter → Blur → Gaussian […]
🧹 One Click, Whole Solution Cleaned Code formatting, unused using removal, sorting members — CodeMaid does it all. Automatic code cleanup on save. 🔧 Features Install: Extensions → CodeMaid Features: – Reorganize members (fields, properties, methods) – Remove unused usings – Sort usings alphabetically – Format document – Remove blank lines – Insert file header […]
♻️ Stop Allocating Temporary Arrays new byte[1024] allocates and GC collects. ArrayPool<T> reuses arrays. Zero allocation for temporary buffers. Huge GC reduction. 📝 Basic ArrayPool Usage using System.Buffers; // Rent array (might be larger than requested) byte[] buffer = ArrayPool.Shared.Rent(1024); try { // Use buffer await stream.ReadAsync(buffer, 0, 1024); Process(buffer); } finally { // Return […]
⚡ Delegate Overhead? Use Function Pointers. Delegates are fast, but not zero-cost. Function pointers (C# 9+) call native code or high-frequency callbacks with minimal overhead. 📝 Basic Function Pointer unsafe { // Delegate (managed) Func addDelegate = (a, b) => a + b; // Function pointer (unmanaged) delegate* addPointer = &Add; int result1 = addDelegate(5, […]
🔍 LIKE ‘%word%’ is Slow LIKE with leading wildcard can’t use indexes. Full-Text Search indexes words. Search millions of rows in milliseconds. 📝 Create Full-Text Index — PostgreSQL CREATE INDEX idx_posts_search ON posts USING GIN (to_tsvector(‘english’, title || ‘ ‘ || content)); — MySQL ALTER TABLE posts ADD FULLTEXT INDEX idx_search (title, content); — SQL […]
⚡ 100x Faster Responses with One Line of Code Same endpoint called repeatedly? Database query every time? Output caching stores HTTP responses. No database, no processing. 📝 Basic Output Caching // Program.cs builder.Services.AddOutputCache(); app.UseOutputCache(); // Controller [ApiController] [Route(“api/[controller]”)] public class ProductsController : ControllerBase { [HttpGet] [OutputCache(Duration = 60)] // Cache for 60 seconds public async […]
⚙️ Run Scripts Automatically on Git Events Run tests before commit? Lint before push? Git hooks automate anything. No more forgotten steps. 📝 pre-commit Hook #!/bin/bash # .git/hooks/pre-commit # Run linter npm run lint if [ $? -ne 0 ]; then echo “❌ Linter failed. Fix errors before commit.” exit 1 fi # Run tests […]
⚡ 30% Faster API Calls Each fetch opens new TCP connection. Handshake overhead. Connection: keep-alive reuses connections. Faster subsequent requests. 📝 Server Configuration # Node.js (Express) const server = app.listen(3000); server.keepAliveTimeout = 60000; // 60 seconds server.headersTimeout = 61000; # Nginx keepalive_timeout 65s; keepalive_requests 100; # Apache KeepAlive On MaxKeepAliveRequests 100 KeepAliveTimeout 5 # IIS […]
📊 _.groupBy() is Finally Native Grouping arrays required Lodash or manual reduce. Object.groupBy() is native. No more dependencies. 📝 Basic GroupBy const users = [ { name: ‘Alice’, role: ‘admin’ }, { name: ‘Bob’, role: ‘user’ }, { name: ‘Charlie’, role: ‘admin’ } ]; const byRole = Object.groupBy(users, user => user.role); // { // admin: […]
🔒 Disable Camera, Microphone, Geolocation by Default Third-party scripts accessing sensitive APIs? Permissions Policy controls which features are allowed. Defense in depth. 📝 HTTP Header # Disable everything Permissions-Policy: geolocation=(), camera=(), microphone=(), payment=() # Allow only same origin Permissions-Policy: geolocation=(self), camera=(self) # Allow specific domains Permissions-Policy: geolocation=(self “https://trusted.com”) # Allow all (default) Permissions-Policy: geolocation=* 🎯 […]
📐 CSS Variables Now Have Types! CSS variables are strings. @property defines types: number, color, length. Enables smooth transitions. 📝 Defining Typed Properties @property –progress { syntax: ”; inherits: false; initial-value: 0%; } @property –primary-color { syntax: ”; inherits: true; initial-value: #3498db; } @property –spacing { syntax: ‘ | ‘; inherits: false; initial-value: 0px; } […]
🗑️ Never Run Disk Cleanup Again Temporary files, recycle bin, downloads folder — fill your disk. Storage Sense cleans automatically. Set it and forget it. 🔧 Enable Storage Sense Settings → System → Storage → Storage Sense → On Configure: – Run Storage Sense: Every day / Week / Month / Low disk space – […]
📚 Turn // Comments into Beautiful Documentation JSDoc, XML comments, docstrings are structured. AI converts comments to Markdown docs. Publish anywhere. 📝 The Prompt Convert these code comments into API documentation: [Paste code with JSDoc/XML comments here] Requirements: – Generate readable Markdown – Include function signatures with types – Add example usage for each function […]
🔑 npm install Needs Token. But Token Shouldn’t Be in Image. Build-time secrets (npm tokens, SSH keys) often leak into layers. Docker BuildKit secrets mount secrets at build time, never stored. 📝 Dockerfile with Secrets # syntax=docker/dockerfile:1.4 FROM node:18 AS builder WORKDIR /app COPY package*.json ./ # Secret mount (not stored in layer) RUN –mount=type=secret,id=npmrc […]
🛡️ Don’t Drain All Pods at Once Node draining, cluster upgrades kill pods. PodDisruptionBudget (PDB) ensures minimum availability during voluntary disruptions. 📝 PDB Examples # At least 2 pods available at all times apiVersion: policy/v1 kind: PodDisruptionBudget metadata: name: app-pdb spec: minAvailable: 2 selector: matchLabels: app: myapp # No more than 1 pod unavailable apiVersion: […]
💾 WP_Query Too Slow? Go Direct. WP_Query is convenient but slow for complex reports. $wpdb runs raw SQL. 100x faster for large datasets. 📝 Basic $wpdb global $wpdb; // Get single value $user_count = $wpdb->get_var(“SELECT COUNT(*) FROM {$wpdb->users}”); // Get single row $user = $wpdb->get_row(“SELECT * FROM {$wpdb->users} WHERE ID = 123”); // Get all […]