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Introduction Modern software systems are distributed, complex, and constantly changing. When something breaks in production, you need answers fast. That's where observability comes in. Observability is the ability to understand the internal state of a system purely from its external outputs — without needing to redeploy, add debug code, or guess. It goes beyond traditional monitoring, which only tells you whether something is wrong. Observability tells you why it's wrong, where it started, and how it's spreading. In this article, we'll explore the three pillars of observability, set up a real Node.js API instrumented with Prometheus and Grafana , and walk through how to detect and diagnose a real-world issue using the data we collect. The Three Pillars of Observability 1. Logs Logs are discrete, timestamped records of events that happened in your system. They're the most familiar form of observability — every developer has done console.log debugging at some point. Example: [2026-07-02T10:34:21Z] INFO User 4821 logged in from IP 192.168.1.10 [2026-07-02T10:34:25Z] ERROR Failed to process payment for order #9932: timeout Logs are great for capturing specific events, errors, and context. But they can become expensive at scale and hard to query across millions of lines. 2. Metrics Metrics are numeric measurements collected over time. Unlike logs, they're aggregated and efficient to store and query. Common examples: HTTP request count per minute p95 response latency CPU and memory usage Error rate per endpoint Metrics are the backbone of dashboards and alerts. 3. Traces Traces follow a single request as it travels across multiple services. In a microservices architecture, a user request might touch 5–10 services. A trace shows you exactly where time was spent and where failures occurred. Tools like Jaeger , Zipkin , and OpenTelemetry handle distributed tracing. Why Prometheus and Grafana? There are many observability platforms out there: Datadog, New Relic, Dynatrace, Az

I used to spend ten hours every week doing content research manually. Checking competitor blogs. Scanning Reddit threads. Copying and pasting search results into a spreadsheet. Trying to spot patterns in an ocean of unstructured text. It was exhausting, slow, and completely unnecessary. Once I learned to automate this with Python and a few affordable APIs, I cut that ten-hour grind down to under thirty minutes. Here is the exact system I built, what it costs, and how you can replicate it yourself. The Quick Answer To automate content research with Python, combine a search API like Serper to pull structured Google search data, BeautifulSoup or requests-html to parse page content, and an LLM API like Gemini to synthesize insights into actionable content briefs. Connect these three components in a sequential Python pipeline and you have a fully automated research agent that runs in minutes instead of hours. What I Actually Built I needed a system that could do three things automatically: First, find what real people are asking about any topic across Reddit, Quora, and Google search. Second, identify what my top competitors have written about that topic and where the gaps are. Third, summarize everything into a clean content brief I can use to write or generate an article. I built this using Python with three core components: the Serper API for search data, BeautifulSoup for page parsing, and the Google Gemini API for synthesis. Total monthly cost: about twelve dollars. I document the full working version of this system — including the Flask web interface and WordPress publishing integration — at https://zerofilterdiary.com Step-by-Step Build Guide Step 1: Install the Required Libraries pip install requests beautifulsoup4 python-dotenv google-generativeai Step 2: Set Up Your API Keys Create a .env file in your project root: SERPER_API_KEY=your_serper_key_here GEMINI_API_KEY=your_gemini_key_here Step 3: Search for Real Discussions Using Serper API import requests import

Testing a food delivery app is hard. Testing an on-demand logistics app is harder. Food delivery has...

We need to have a serious talk about the Model Context Protocol. Everyone is losing their minds over "vibe coding" right now. You plug an MCP server into Cursor, Claude Code, or VS Code, tell the AI to fix a bug across three directories, and go grab a coffee while it spins up local servers, reads files, and executes terminal commands. It feels like absolute magic. But honestly? It's also completely terrifying. Maybe I’m just paranoid, but it seems like we’ve collectively skipped the part where we ask ourselves if giving a statistical text-prediction engine raw, unvetted access to our local machines is a good idea. Some security folks are already warning that we’re walking directly into a massive remote code execution crisis. Think about it. Most MCP servers run as local subprocesses. They inherit your exact user permissions. If you run your editor as an admin or with access to sensitive environment variables, so does the AI. And the real issue isn't that the AI will spontaneously turn evil. The issue is prompt injection. The Security Void in the Hype I spent some time looking through public MCP servers on GitHub recently, and the sheer lack of input validation is wild. Because developers are rushing to build cool tools, basic security hygiene has completely lagged behind. If an AI agent reads an untrusted string—like a malicious comment in a GitHub issue, an automated email, or a dirty record inside a database—it can easily be manipulated into executing an injection payload. The model doesn't know the difference between your system instructions and the data it's processing. It treats them exactly the same. What happens when a prompt injection tricks a standard filesystem MCP tool into looking for a file named ../../../../../../etc/passwd or pulling your private AWS keys? The tool just does it. It’s a classic path traversal vulnerability, except instead of a malicious hacker typing it into a web form, an automated agent is doing it because a piece of text told it to.

The Problem When you put RabbitMQ's Management UI behind an nginx reverse proxy under a sub-path like /rabbitmq/ , queue detail pages and many API calls break silently. The root cause: nginx normalizes the request URI before proxying. It decodes %2F (the URL-encoded forward slash) into a literal / . RabbitMQ's Management API uses %2F to represent the default virtual host ( / ) in API paths: GET /api/queues/%2F/my-queue When nginx decodes it: GET /api/queues///my-queue ← broken What Doesn't Work The common advice of using merge_slashes off or a rewrite directive doesn't fully solve this because nginx still normalizes $uri before forwarding. The Fix Use $request_uri inside an if block. Unlike $uri , $request_uri holds the raw, undecoded URI exactly as the client sent it — nginx never touches it. nginx # RabbitMQ: API paths — use $request_uri to preserve %2F (never decoded by nginx) location ~* ^/rabbitmq/api/ { if ($request_uri ~* "^/rabbitmq/(.*)") { proxy_pass http://rabbitmq:15672/$1; } proxy_buffering off; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Forwarded-Proto https; } # RabbitMQ: general UI (JS, CSS, static assets, non-API pages) location ~* ^/rabbitmq/ { rewrite ^/rabbitmq/(.*)$ /$1 break; proxy_pass http://rabbitmq:15672; proxy_buffering off; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Forwarded-Proto https; }

Pernah kepikiran, "Sebenarnya AI agent saya inget apa aja sih soal saya?" Kalau iya, tulisan ini buat kamu. Masalahnya: Memori AI Itu Kotak Hitam Kalau kamu pakai AI agent yang punya memori jangka panjang (persistent memory), kamu mungkin pernah ngerasa gak nyaman karena beberapa hal ini: Gak tahu persis apa yang diingat AI tentang kamu Gak tahu file-nya disimpan di mana Gak bisa edit memori itu tanpa ngetik perintah lewat chat Takut kalau file memorinya rusak, semua informasi hilang begitu saja Studi kasus di tulisan ini pakai Hermes Agent , agent open-source besutan Nous Research. Sebagai konteks buat yang belum familiar: Hermes Agent adalah agent AI open-source yang berjalan sebagai proses (daemon) mandiri di server milikmu sendiri, mengumpulkan memori lintas sesi, menjalankan tugas terjadwal, terhubung ke belasan platform pesan, dan menulis skill-nya sendiri dari pengalaman. Framework berlisensi MIT ini dirilis Februari 2026 dan dengan cepat menarik perhatian komunitas open-source AI. Hermes menyimpan memorinya di dua file utama: USER.md (profil tentang kamu) dan MEMORY.md (catatan agent soal lingkungan kerja, kebiasaan, dan pelajaran yang dipetik), plus satu file lagi SOUL.md untuk "kepribadian" si agent. Semuanya disimpan dalam format teks polos yang dipisah pakai karakter § , seperti ini: Preferensimu: komunikasi singkat dan langsung § Namamu Budi, awal 30-an, tinggal di Surabaya § Penggemar PKM / Building a Second Brain Format ini fungsional, tapi ada beberapa kekurangan: Susah diedit langsung karena bukan format yang ramah manusia Gak ada riwayat versi — sekali salah edit, informasi bisa hilang selamanya Gak ada tampilan visual — susah lihat semua catatan sekaligus Gak ada antarmuka grafis — harus lewat chat agent atau edit file mentah Solusinya: pindahkan memori itu ke Obsidian , aplikasi catatan berbasis markdown yang mendukung riwayat versi lewat git dan bisa diedit bebas. Arsitektur Sistemnya Sistem sinkronisasi ini punya empat lapisan: ┌───────────────

An AI feature can feel impressive and still be a bad product decision. The demo is fast. The answer sounds useful. The team is excited. Then usage grows and nobody can answer the basic questions: Is it accurate enough? Is it saving time? Which customers trust it? Why did costs spike? Should we scale it, fix it, or kill it? That is the trap an AI metrics baseline prevents. A baseline is not a dashboard full of vanity charts. It is a small set of before-and-after measurements that tells you whether an AI workflow is getting better, getting worse, or merely getting more expensive. Why AI features fail without a baseline Most software teams already track uptime, errors, and conversion. AI features need those too, but they also need new signals because model behavior is probabilistic. A normal API either returns the expected response or throws an error. An AI workflow can return: a fluent answer that is wrong a correct answer with missing evidence a useful answer that costs too much a slow answer that users abandon a safe answer that refuses too often a cheap answer that hurts trust a high-rated answer that does not improve the business workflow Without a baseline, every production discussion becomes opinion-driven: "The model seems better." "Users like it." "The new prompt reduced hallucinations." "The expensive model is worth it." Maybe. Maybe not. The baseline turns those claims into measurable comparisons. What an AI metrics baseline is An AI metrics baseline is the starting measurement for the workflow before you optimize or scale it. It answers five questions: What does the workflow cost today? How good are the outputs today? How fast and reliable is the experience today? Do users adopt and reuse it? Does it improve the real task it claims to improve? You do not need 80 metrics on day one. You need a small set of metrics that match the feature's risk and purpose. For example: Feature Useful baseline Support answer bot resolution rate, citation quality, escalation r

The Token Bucket Algorithm: Server-Side API Rate Limiting in ~40 Lines Plenty of tutorials teach you how to survive someone else's rate limit with retries and backoff. Far fewer show you how to build one. If you run an API, you need rate limiting on your side too — to protect your database from a runaway client, keep one noisy tenant from starving everyone else, and give abusive traffic a polite 429 instead of a melted server. The cleanest algorithm for the job is the token bucket . Let's implement it from scratch, then make it production-ready. How token bucket works Picture a bucket that holds up to capacity tokens. Every request removes one token. The bucket refills at a steady refillRate (tokens per second), up to its cap. If a request arrives and the bucket is empty, it's rejected. This gives you two useful properties at once: A sustained rate — the long-run average, set by refillRate . A burst allowance — clients can spend the whole bucket at once, set by capacity . That burst tolerance is why token bucket feels fair. A user who's been quiet for a minute can fire off a batch of requests without being punished for it. A minimal implementation Here's a self-contained bucket in JavaScript. No dependencies, no timers — we compute refill lazily based on elapsed time, which is both simpler and more accurate than a background interval. class TokenBucket { constructor ( capacity , refillRatePerSec ) { this . capacity = capacity ; this . refillRate = refillRatePerSec ; this . tokens = capacity ; this . lastRefill = Date . now (); } _refill () { const now = Date . now (); const elapsedSec = ( now - this . lastRefill ) / 1000 ; this . tokens = Math . min ( this . capacity , this . tokens + elapsedSec * this . refillRate ); this . lastRefill = now ; } take ( cost = 1 ) { this . _refill (); if ( this . tokens >= cost ) { this . tokens -= cost ; return { ok : true , remaining : Math . floor ( this . tokens ) }; } const deficit = cost - this . tokens ; const retryAfter = Mat

Web Scraping with Python in 2026: Best Libraries and Anti-Bot Strategies Web scraping in 2026 looks very different from 2020. Sites are smarter, anti-bot systems are more aggressive, and the legal landscape has evolved. Here's what actually works now. The 2026 Scraping Landscape Challenge 2020 Solution 2026 Solution Bot detection Rotate User-Agent Fingerprint randomization + residential proxies CAPTCHAs Manual solving Turnstile/hCaptcha solvers JavaScript rendering Selenium Playwright (faster, more reliable) Rate limiting Sleep between requests Adaptive pacing + request signing IP blocking VPN rotation Residential proxy pools Best Libraries in 2026 1. Playwright (Best for JS-heavy sites) from playwright.sync_api import sync_playwright def scrape_with_playwright ( url ): with sync_playwright () as p : browser = p . chromium . launch ( headless = True ) page = browser . new_page () page . goto ( url , wait_until = " networkidle " ) data = page . query_selector_all ( " .job-item " ) results = [] for item in data : title = item . query_selector ( " h2 " ). text_content () results . append ( title ) browser . close () return results 2. httpx + Selectolax (Fast, no JS needed) import httpx from selectolax.parser import HTMLParser def scrape_static ( url ): resp = httpx . get ( url , headers = { " User-Agent " : " Mozilla/5.0 " }) tree = HTMLParser ( resp . text ) for node in tree . css ( " .listing " ): print ( node . text ()) 3. API-First Approach (Always check first!) Many sites have hidden or public APIs that make scraping unnecessary: url = " https://www.freelancer.com/api/projects/0.1/projects/active/?query=python " data = httpx . get ( url ). json () Anti-Bot Strategies That Work 1. Request Fingerprint Randomization import random def get_random_headers (): browsers = [ " Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 " , " Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 " , ] return { " User-Agent " : random . choice ( browsers ), " A

Breaking long documents into overlapping chunks, preserving context, and reassembling with FastAPI At LectuLibre, we’ve built an AI‑powered platform that translates entire books—EPUBs and PDFs—using large language models. When we first hooked up Claude’s API, we naively fed it a 300‑page PDF in one request. It failed immediately. Claude 3 Opus has a 200K token window, but a 300‑page book can easily run to 300K tokens or more. Even if we squeezed it in, the output would be truncated and the quality would degrade at the extremes of the context window. So we faced a classic long‑document problem: how do you translate a book that’s larger than the model’s context window? Here’s the real approach we ended up with, the code we wrote, and the lessons we learned. The Problem: Token Limits Are Real Claude 3 Opus and Haiku models (and most LLMs) have a maximum context length—200,000 tokens for Opus. A token is roughly ¾ of a word. A 300‑page novel with ~75,000 words translates to about 100K tokens, so it should fit, right? But translations from English to Spanish can expand by 15–20%, and the prompt instructions, system message, and the user message itself all eat into that budget. Plus, we needed to send the entire source text in every call to give the model full context. That’s not feasible. We could have tried a simple split: cut the book at arbitrary page boundaries and translate piecemeal. That fails spectacularly. Narrative breaks mid‑sentence, and phrases like “the previous chapter” lose their referents. We needed a more intelligent chunking strategy. Our Approach: Sliding Window with Overlapping Paragraphs We settled on a sliding window chunking algorithm based on paragraphs, with a generous overlap. Here’s the idea: Split the source text into paragraphs (using \n\n ). Build chunks of max_chunk_tokens (we used 180,000 to keep a safety margin), adding paragraphs one by one and counting tokens with tiktoken . When the chunk exceeds the limit, we start a new chunk but we

It's pretty common to throw a layer of HTTP Basic auth on a WordPress site: a staging environment before launch, an internal test instance only employees should see, or any environment that wants an extra gate before the WordPress login screen itself. From a maintenance-tool point of view, this setup creates a peculiar "half-working, half-broken" asymmetry. The SSH/WP-CLI side runs fine. But everything HTTP-based — visual checks, thumbnail generation, browser-based fallback updates — hits 401 and dies. This post walks through how we resolved that asymmetry. What was breaking — two parallel paths, both blocked A maintenance tool actually touches a Basic-auth-protected site through two distinct paths: Playwright path : visual checks, thumbnail capture, browser fallback updates when SSH isn't available. browser.new_context() → navigation → screenshot urllib path : HTTP status checks (pre/post-update 200/5xx/4xx monitoring, rollback decisions) With no credentials, both paths see a 401 Unauthorized from the protected site. The Playwright symptom is the obvious one: the screenshot you save is the browser's "authentication required" dialog. The thumbnail grid fills with dark auth-prompt images, and you start wondering whether anything actually works. The urllib symptom is much worse — it silently breaks rollback decisions . A 401 baseline followed by another 401 after the update looks like "nothing changed = healthy." Real failures can hide behind that match, and the rollback that should have fired never does. The design — consolidate credential extraction into one helper When the same credentials need to flow through multiple code paths, picking them out of the site dict separately at each call site invites format-mismatch and missed-update bugs. So the first thing we did was build a small core/basic_auth_utils.py module that owns every form of credential extraction . # core/basic_auth_utils.py def get_basic_auth_tuple ( site ): """ Return (user, password), or None if not

WebMCP lets a web page expose tools that AI agents can discover and execute inside the browser. That...

I've been building on DynamoDB since around 2015, and these days I build tools for it: dynoxide , a DynamoDB engine, and Nubo , a native client. So I'm not neutral about it. It's the first database I reach for, and with reason - the operational overhead is close to nil, no connections to pool or instances to size, and it holds the same single-digit-millisecond reads whether the table has a thousand items or a billion. The data modelling is a craft, and a satisfying one. It's also one of the harder databases to learn, and that's the part I keep coming back to. DynamoDB punishes the instincts you bring from SQL. You don't normalise and join at read time; you work out the questions your app will ask first, and shape the data around those access patterns, until one table answers all of them. It's a real shift in how you think, and it's where a lot of people bounce off - it feels backwards right up until it clicks. The people who teach it best all teach it the same way. Alex DeBrie's The DynamoDB Book , the arc.codes team's examples, Rick Houlihan's re:Invent talks - the legendary ones, where he models half a dozen access patterns onto a single table at a hundred miles an hour - none of them hand you rules to memorise. They show you patterns and make you run them. I learned a lot of my DynamoDB from all three, and it stuck because I was building as I went. That last part is the bit that's hard to come by on your own. Reading about an access pattern and having it in your fingers are different things, and to run one - build the table, write the items, fire the query and see what comes back - you need an AWS account, or a local emulator installed and seeded. Enough friction that plenty of people read about single-table design without ever building one. There was a second thing pulling the same way. dynoxide had learned to run in the browser only last month, compiled to WebAssembly with no server behind it, and it was a preview I didn't fully trust. What it needed was a real

If you've ever worked with e-commerce data, you know that "a pair of jeans" is never just one product. A single style might come in 5 washes, 8 sizes, and 3 inseam lengths. That's 120 potential SKUs. Handling this correctly in an API can be tricky, so let me share a pattern I've used for structuring product variants. The core problem is balancing flexibility with performance. You want customers to filter by size, color, and fit without making dozens of API calls. Here's a simple but effective approach using a normalized database schema with a flat query layer: -- Products table (the "parent") CREATE TABLE products ( id UUID PRIMARY KEY , name TEXT NOT NULL , description TEXT , base_price DECIMAL ( 10 , 2 ), category TEXT ); -- Variants table (the actual sellable items) CREATE TABLE variants ( id UUID PRIMARY KEY , product_id UUID REFERENCES products ( id ), sku TEXT UNIQUE NOT NULL , size TEXT , color TEXT , wash TEXT , inseam TEXT , price DECIMAL ( 10 , 2 ), -- can override base price stock_quantity INT , image_url TEXT ); The key insight? Keep the product metadata (description, care instructions, brand story) in the products table, but put all the sellable attributes in variants. This lets you run queries like: -- Find all size 28 jeans in "mid wash" under $80 SELECT p . name , v . color , v . wash , v . price , v . stock_quantity FROM products p JOIN variants v ON p . id = v . product_id WHERE p . category = &# 039 ; women - jeans &# 039 ; AND v . size = &# 039 ; 28 &# 039 ; AND v . wash LIKE &# 039 ; % mid %&# 039 ; AND v . price & lt ; 80 AND v . stock_quantity & gt ; 0 ORDER BY v . price ; For the frontend, I usually return a flattened structure: { "product": { "id": "abc -123 " , "name": "Classic Straight Leg Jean" , "description": "High-rise fit in stretch denim..." , "availableSizes": [ " 24 " , " 25 " , " 26 " , " 27 "

Most developers have experimented with ChatGPT or GitHub Copilot. But when it comes to building AI-powered applications, simply calling an LLM API isn't enough. Understanding what's happening behind the scenes helps you design systems that are scalable, reliable, and cost-effective. In this article, we'll explore four concepts every software engineer should know: tokens, embeddings, transformers, and Retrieval-Augmented Generation (RAG). 1. LLMs Think in Tokens, Not Words One of the biggest misconceptions about Large Language Models (LLMs) is that they understand words like humans do. In reality, they process tokens, which are smaller units of text. For example: Prompt: Explain dependency injection in Spring Boot. is first converted into a sequence of tokens before the model processes it. Why does this matter? API pricing is based on the number of input and output tokens. Longer prompts increase latency and cost. Every model has a maximum context window measured in tokens. When building AI applications, prompt design isn't just about getting better answers—it's also about optimizing performance and cost. 2. Transformers: The Breakthrough Behind Modern AI Before 2017, language models processed text one word at a time using architectures like RNNs and LSTMs. They struggled with long conversations because earlier context was gradually forgotten. The introduction of the Transformer architecture changed this with a mechanism called self-attention. Instead of reading text sequentially, transformers analyze the relationships between all tokens in a sentence simultaneously. Consider this sentence: "The server restarted because it ran out of memory." The model understands that "it" refers to "the server", not "memory", by assigning attention to the relevant words. This ability to capture context efficiently is what powers modern LLMs like GPT, Gemini, Claude, and Llama. 3. Embeddings Enable Semantic Search Suppose a customer searches: "How can I get my money back?" But your

React useIntersectionObserver Hook: Lazy Load & Detect Visibility (2026) You want to load an image only when it scrolls near the viewport. Or fire an analytics event the first time a card is actually seen . Or trigger "load more" when the user reaches the bottom of a list. Every one of these is the same question — is this element on screen yet? — and for years the answer was a scroll listener that fired hundreds of times a second, re-read getBoundingClientRect() on each tick, and still managed to miss the edge cases. IntersectionObserver is the browser API that answers that question correctly, asynchronously, and off the main thread. useIntersectionObserver is the hook that wires it into React without the useEffect / useRef /cleanup boilerplate — and without the leak-on-unmount and stale-closure bugs the hand-rolled version always ships. This post covers the real @reactuses/core API, the three patterns you'll actually reach for, and how to tune threshold , rootMargin , and root . SSR-safe and typed. Why Not Just Use a Scroll Listener? The old way to know whether an element was visible looked like this: listen to scroll , and on every event measure the element against the viewport. useEffect (() => { function onScroll () { const rect = el . getBoundingClientRect (); if ( rect . top < window . innerHeight ) { setVisible ( true ); } } window . addEventListener ( ' scroll ' , onScroll ); return () => window . removeEventListener ( ' scroll ' , onScroll ); }, []); This has two problems baked in. First, scroll fires on the main thread, dozens of times per second, and getBoundingClientRect() forces a synchronous layout each time — that's exactly the recipe for janky scrolling. Second, it only catches elements crossing the viewport ; the moment your scroll happens inside a container, you're re-deriving geometry by hand. IntersectionObserver flips the model. You hand the browser a target and a threshold, and it tells you — asynchronously, batched, off the scroll path — when

🚀 Build Your First Space Shooter Game with Limn Engine A Complete Step-by-Step Tutorial for JavaScript Beginners Welcome! In this tutorial, you'll build a complete space shooter game using Limn Engine — a zero‑configuration 2D game engine that runs in your browser. What you'll build: A spaceship that moves, shoots bullets, fights waves of enemies, and keeps score. All in about 100 lines of code . By the end, you'll understand: How to create a game loop How to handle keyboard input How to detect collisions How to use particles for visual effects How to manage game state (lives, score, game over) 🎮 Want to play the finished game? Click here to play Space Shooter Live! Before We Start What You Need A text editor (VS Code, Notepad, or any code editor) A web browser (Chrome, Firefox, Edge) Limn Engine — download epic.js from limn-engine-doc.vercel.app What You Should Know Basic JavaScript (variables, functions, arrays, if-statements) How to open an HTML file in a browser No game development experience required! Step 1: The HTML Structure Every Limn Engine game starts with a simple HTML file. <!doctype html> <html> <head> <script src= "asset/epic.js" ></script> </head> <body> <script> // All your game code goes here </script> </body> </html> What's happening: <script src="asset/epic.js"> — loads the Limn Engine library Everything inside the second <script> tag is your game code Save this as game.html and open it in your browser. You should see a blank canvas with a blue gradient background. Step 2: Setting Up the Game The first thing we need is a Display — this is the engine that creates the canvas, runs the game loop, and handles input. const display = new Display (); display . perform (); // Activates performance mode (dual-canvas rendering) display . start ( 800 , 600 ); // Creates an 800×600 canvas What's happening: new Display() — creates the engine display.perform() — turns on high-performance mode display.start(800, 600) — creates a canvas 800 pixels wide and 600 p

One day a multi-site administrator reported a strange bug: "After running the app's SSH connection test 2-3 times, my IP can't reach SSH on that server for a long while ." The errors came back as Connection refused or Connection closed by ... . The server wasn't down, and SSH from a different IP worked fine. The source IP was being temporarily banned at the server. Two external investigation reports gave the cause: server-side protection mechanisms ( fail2ban or PerSourcePenalties in OpenSSH 25+) detect short-windowed authentication failure spikes and temporarily ban the source IP. But the user had only clicked the test button 2-3 times — why were failures "spiking"? The answer turned out to be paramiko's default behavior . paramiko's default — trying many keys per connection paramiko.SSHClient.connect() defaults two options to True : client . connect ( ' host ' , pkey = my_key , # The following are True by default: # look_for_keys=True, # also try ~/.ssh/id_* files # allow_agent=True, # also try ssh-agent registered keys ) When the explicitly passed pkey fails, paramiko falls back through ssh-agent registered keys → ~/.ssh/id_* files → password auth in order. Convenient for developers with a single key. Disastrous for a multi-site administrator: The SSH agent has multiple per-site keys registered ~/.ssh/ holds several id_rsa / id_ed25519 files A single connect call ends up trying 5-10 keys in sequence That blows past the server's MaxAuthTries (default 6) on a single connection So what looked to the user like "one connection test" was being seen by the server as " a suspicious IP racking up 5-10 auth failures in a row ." Repeat that 2-3 times and the protection mechanism declares the IP "exceeded threshold" and bans it. The fix — look_for_keys=False and allow_agent=False paramiko exposes options to scope key trial. We set them explicitly in connect_kwargs : connect_kwargs = { ' pkey ' : my_key , ' look_for_keys ' : False , # don't try ~/.ssh/id_* ' allow_agent ' : F

You export a CSV from a UK system and double-click it in US Excel — 28/05/2026 suddenly looks like May 28, or something even stranger. The file isn't corrupt. Excel is guessing your date format based on your computer's locale. This short guide covers why that happens, how to import CSV correctly, and how to batch-fix dates that are already wrong. For the full walkthrough with examples, see the official guide: How to Fix Excel CSV Date Import Problems . Why Excel breaks CSV dates A CSV is plain text. It does not store whether a value is a date or a string. When you double-click to open, Excel parses using your regional settings: US Excel: MM/DD/YYYY UK / Europe: DD/MM/YYYY Dates like 03/04/2025 are the most dangerous — both parts are ≤ 12. US Excel may read April 3; UK Excel reads March 4. Excel won't warn you. Other common traps: Dates exported as serial numbers (e.g. 44927 ) Two-digit years triggering century guesses Re-saving as CSV destroys formats a second time The right way: don't double-click the CSV Open Excel first — don't double-click the .csv file Data → Get Data from Text/CSV (older Excel: Data → From Text) Set date columns to Text if you need to preserve the original string Confirm the source region (US / UK), then convert to a single format For team data exchange, agree on ISO 8601: YYYY-MM-DD in your schema — unambiguous, sorts correctly as text, and works in JSON APIs and databases. Ambiguous value US reads as UK reads as Safe format (ISO) 03/04/2025 2025-04-03 2025-03-04 Confirm source region 28/05/2026 — 2026-05-28 2026-05-28 05/28/2026 2026-05-28 — 2026-05-28 Already broken? Fix dates in the browser (no server upload) I built a free tool cluster on FormatList — everything runs locally in your browser : 1. Date Format Fixer — bulk repair Paste a date column or upload .csv / .txt Ambiguous rows highlighted; optional US / UK preference Export ISO / US / UK or download a fixed CSV Best for: normalizing a whole column to ISO before a database or API imp

AI crawlers now appear in many server logs alongside traditional search bots. Some are used for search retrieval, some for training, and some for broader web indexing. If you care about AI search visibility, you need to know which ones can access your public pages. The most common accidental blocker is simple: a robots.txt rule or CDN bot setting that prevents AI crawlers from reaching the content you want discovered. The major AI crawler tokens to check Here are crawler tokens you may see in logs or robots.txt rules: Crawler token Company Notes GPTBot OpenAI Documented OpenAI crawler token OAI-SearchBot OpenAI Documented OpenAI search-related crawler token ChatGPT-User OpenAI Documented OpenAI user-triggered agent token ClaudeBot Anthropic Documented Anthropic crawler token Claude-SearchBot Anthropic Documented Anthropic search-related crawler token Google-Extended Google Google control token for Gemini Apps and Vertex AI use CCBot Common Crawl Web corpus crawler used by many downstream systems PerplexityBot Perplexity Commonly referenced Perplexity crawler token Crawler names and purposes change. Always confirm against official platform documentation before making sitewide access decisions. First, check what is actually happening Before you change anything, find out who is already crawling. If you have server logs: grep -E "GPTBot|OAI-SearchBot|ChatGPT-User|ClaudeBot|Claude-SearchBot|Google-Extended|CCBot|PerplexityBot" access.log If you use Cloudflare, check bot and security events and filter by user agent. Three quick diagnostic steps: Open https://yourdomain.com/robots.txt and look for broad Disallow: / rules. Confirm the sitemap is listed in robots.txt or discoverable at /sitemap.xml . Use our AEO Checker to validate robots.txt and flag restrictive AI crawler rules. The most common mistake The blunt rule that makes sites invisible to many crawlers: User-agent: * Disallow: / This blocks every well-behaved crawler that follows the wildcard rule. If you see it on