标签：#p

Tilt a CD or DVD under a desk lamp and a band of color sweeps across its surface. The disc is not painted; it is a spiral of microscopic pits, packed so tightly that they act on light the way a finely ruled scientific instrument does. Each wavelength of white light leaves the surface at its own angle, and your eye sees the result fanned out as a rainbow. That is a diffraction grating at work. The same principle that decorates a CD is the engine inside spectrometers that identify chemical elements, tune lasers, and read the composition of distant stars. This article explains how a grating spreads light, how to compute the angles, and where the analysis goes wrong. Why this calculation matters A prism also splits white light, but a grating does it with far more control and far more precision. Because the spreading depends on a countable number — the spacing between lines — a grating can be designed to send a chosen wavelength to a chosen angle. That predictability is what makes it the heart of the spectrometer. Spectroscopy underpins a remarkable range of work. Astronomers read a star's chemistry and velocity from the dark lines in its spectrum. Chemists identify unknown compounds by the wavelengths they absorb. Telecommunications engineers use gratings to combine and separate the many wavelengths sharing a single optical fiber. In every case the first task is the same: given the grating and the light, predict the angle at which each wavelength emerges. Get that wrong and a spectral line lands on the wrong detector pixel, and the measurement is meaningless. The core formula A diffraction grating is a surface ruled with a large number of equally spaced, parallel lines. When light passes through or reflects off it, each line acts as a source of secondary waves. Those waves interfere, and they reinforce each other only in specific directions — the directions where waves from neighboring lines arrive exactly in step. The condition for that reinforcement is the grating equ

Originally published at ffmpeg-micro.com If you've tried running FFmpeg inside a Pipedream workflow, you've probably hit one of two walls: the step timed out before processing finished, or the FFmpeg binary wasn't available. These are the most common complaints in Pipedream community threads, and neither has a clean workaround. Why FFmpeg Breaks in Pipedream Pipedream workflows run Node.js steps with a 30-second default execution timeout . Paid plans extend that to 300 seconds. But even five minutes isn't enough to transcode most videos. A 10-minute 1080p file can take 3-8 minutes to process depending on the codec and output settings. Longer videos or higher-quality encodes blow past that limit every time. The timeout kills your step mid-execution. No partial output. No graceful failure. Just a dead workflow. Then there's the binary problem. FFmpeg isn't available in Pipedream's runtime environment. Developers on the Pipedream community forums have tried downloading the static binary at runtime, setting PATH variables, and running chmod inside a Node.js step. Some of these hacks work intermittently. Most break the next time Pipedream updates its execution environment. And even if you solve both problems, Pipedream steps have memory constraints that make video processing unreliable. A single high-resolution transcode can exhaust available RAM and crash silently. The Fix: Call an FFmpeg API Instead The timeout issue goes away when you stop running FFmpeg inside the workflow. Make an HTTP request to an external API instead. The API processes the video on its own infrastructure with no time limit. Your Pipedream step sends the request, gets back a job ID, and moves on. FFmpeg Micro processes video through a standard REST API, so any Pipedream HTTP step can call it. No marketplace plugin to install. No binary to configure. Just a POST request and a polling loop. This is different from tools like Rendi or Renderio.dev that require a native Pipedream marketplace integratio

Originally published at ffmpeg-micro.com You need server-side video processing in your Swift app. Maybe you're building a Vapor backend that transcodes user uploads, a macOS utility that batch-converts media files, or a command-line tool that generates thumbnails. FFmpeg is the standard tool for the job, but getting it into a Swift project isn't as simple as adding a package dependency. Running FFmpeg from Swift with Process Swift's Foundation framework provides the Process class for running external commands. If FFmpeg is installed on the machine, you can shell out to it directly: import Foundation let process = Process () process . executableURL = URL ( fileURLWithPath : "/opt/homebrew/bin/ffmpeg" ) process . arguments = [ "-i" , "input.mp4" , "-c:v" , "libx264" , "-crf" , "23" , "-preset" , "medium" , "-c:a" , "aac" , "-b:a" , "128k" , "output.mp4" ] let pipe = Pipe () process . standardOutput = pipe process . standardError = pipe try process . run () process . waitUntilExit () let data = pipe . fileHandleForReading . readDataToEndOfFile () let output = String ( data : data , encoding : . utf8 ) ?? "" print ( output ) guard process . terminationStatus == 0 else { fatalError ( "FFmpeg failed with exit code \( process . terminationStatus ) " ) } This works on macOS and Linux. Install FFmpeg with brew install ffmpeg on macOS or apt-get install ffmpeg on Ubuntu, point executableURL at the binary, and you're running. But you own that FFmpeg install on every machine. On Linux servers, you're managing the binary across deploys. On macOS CI runners, you're adding Homebrew steps to your build pipeline. And on iOS, Process doesn't exist at all. Processing Video via Cloud API (No FFmpeg Install) Skip the local binary entirely. FFmpeg Micro exposes full FFmpeg capabilities through a REST API. Send a video URL, pick your settings, get processed video back. If you're familiar with how this works in Node.js or Kotlin , the pattern is identical. Here's the basic flow using URLSe

A while back I wrote about 64% of our merged PRs being written by AI . A few people (reasonably) asked: "nice story, but can I verify any of that?" So we put it on a public, auto-updating dashboard: 👉 www.codens.ai/stats/en It shows, for our GitHub organization: What % of merged PRs are authored by AI agents (currently 65%) Median time from PR-open to merge (2 minutes) Who merged what — task-execution agents vs maintenance bots vs auto-fix vs humans Weekly AI-merge counts and a per-repository breakdown Every number is tallied straight from the GitHub API by a small collector script, and the page regenerates itself weekly. We can't inflate it — it's measured, and the down weeks show up too (that's kind of the point). Why bother making it public Two reasons. 1. "Trust me bro" doesn't scale. When you claim most of your code is AI-written, the only honest move is to expose the raw counts so anyone can sanity-check them. The dashboard is that receipt. 2. It's a live dogfooding test. The whole thing — the PRD, the implementation, the review, the auto-fix on production errors — runs on Codens , our own AI dev-automation suite. If our own numbers ever tanked, the dashboard would be the first place it'd show. Public accountability is a good forcing function. Funny footnote: the dashboard itself was code-reviewed by our own AI reviewer before it shipped, and it caught two real bugs — an OG-image percentage that had drifted out of sync with the live number, and a broken error-fallback that would have blanked the page on malformed data. The tool built to sell "AI reviews your PRs" reviewed the PR that announces it. We'll take it. If you want to see the same machinery on your repos, there's a 14-day free trial (no card): codens.ai . Japanese version of the dashboard is here .

This week's Java roundup for June 29th, 2026, features news highlighting: a new JEP candidate, Strict Field Initialization; point releases of GraalVM, JReleaser, RefactorFirst and Java Operator SDK; maintenance releases of GlassFish and Micronaut; the second milestone release of Grails 8.0; and the beta release of Open Liberty 26.0.0.7. By Michael Redlich

Free API to get Open Graph data, title & images for any URL Discussion | Link

Fortunately, it shouldn't take too much extra space.

To start off, I appreciate the community support I have received on the post about being behind. I am behind, and I can't prove it but does it matter? Achievement that feels shallow on paper FrancisTRᴅᴇᴠ (っ◔◡◔)っ FrancisTRᴅᴇᴠ (っ◔◡◔)っ FrancisTRᴅᴇᴠ (っ◔◡◔)っ Follow Jun 22 I am behind, and I can't prove it but does it matter? # discuss # community # mentalhealth # career 149 reactions 89 comments 4 min read I couldn't respond to every single one because of the overwhelming comments I have received! Rest assure, I will respond to each and every one of you and I am glad to be part of this community! With that said, I want to return the favor to the community about something important. I recently talked to @georgekobaidze and @codingwithjiro in the Virtual Coffee group about life in general. What I notice about our conversation how we ended up talking about regrets and how we should have done this and that. For example, we talked about not networking or not doing beyond the coursework at our University/College because of how non-social we are. Of course, we all have regrets like these and we improve overtime. As we kept the conversation going, there is something that comes down to the root based on the conversations we have and conversations I had overall. One side is that we have regrets and as a result, we improve. We self-reflect on our wants and needs and we improvise from there. For example, for me, I never did networking because of the fear of what other people thinks. I slowly realized that 99% of the irrational thoughts never comes true. Even if it does, I know myself that I could handle the situation. As a result, I took small steps and joined dev.to. We all know where I am at now XD On the other hand, there are people who identifies these regrets they have, but does not act on it. It has become common to college students who says that the "Job Market is Cooked" and that "They are not good enough". To be fair, impostor syndrome is real and yes, the job market is coo

So, a few months ago I got curious about dropshipping — not as a "get rich quick" scheme, but as a real engineering problem. Inventory syncing, pricing algorithms, order routing, supplier APIs... turns out there's a surprising amount of code you can write in this space. Here's my honest breakdown. The Setup I built a small pipeline using Node.js + PostgreSQL that: Pulls product data from multiple suppliers via their APIs Applies dynamic pricing rules (cost-based, competitor-based, and margin-based) Syncs inventory levels every 15 minutes Auto-generates product descriptions using a simple template engine Routes incoming orders to the correct supplier Nothing fancy. Nothing magical. Just plumbing. What Went Right Automation saves real hours. Manually updating 200+ SKUs is soul-crushing. A cron job and a few API calls replaced about 3 hours of daily work. Template-based descriptions at scale. I used a mix of structured product attributes and Handlebars templates to generate descriptions. Not ChatGPT-level prose, but consistent and fast. Price monitoring was the real MVP. A simple scraper that checked competitor prices every 6 hours let me stay competitive without guessing. What Went Wrong Supplier APIs are... inconsistent. Some return JSON. Some return XML. One returned a CSV inside a JSON field. Parsing supplier data became 60% of the project. Race conditions in inventory sync. I sold an item that was out of stock. Twice. Lesson learned: add a buffer threshold and use proper locking. I underestimated customer support automation. Tracking numbers, returns, delays — this is where the "boring" engineering work actually matters the most. The Creative Part Here's where it got fun. I experimented with: A/B testing product images — randomly serving different hero images and tracking conversion rates Seasonal keyword injection — appending trending search terms to product titles based on Google Trends data A "dead stock" detector — flagging products with zero views in 30 days

How I Cut My LLM API Bill by 40x: A Freelancer's Migration Story Last month I almost choked on my coffee when my OpenAI dashboard showed $487.32 for a single client project. That's not profit. That's a panic attack. As a freelancer running a one-person shop, every line item on my monthly expenses gets scrutinized harder than my code reviews. I spent the next weekend stress-testing alternatives, and honestly? I was annoyed at myself for not doing it sooner. The savings are obscene. Let me walk you through exactly what I found, what I migrated to, and how the switch took maybe 20 minutes total. Let me Start With the Damage Here's what I was paying before. OpenAI's GPT-4o runs $2.50 per million input tokens and $10.00 per million output tokens. For one of my retainer clients — a SaaS company whose support chatbot I maintain — I'm pushing roughly 50 million tokens through a month on input and another 15 million on output. Do the math with me: 50M × $2.50 = $125 on input alone. 15M × $10.00 = $150 on output. That's $275/month just for that one client's chatbot. Add my other three active clients and suddenly I'm staring at a $400-500 OpenAI bill every month like clockwork. For a freelancer, that's a third of a client's monthly retainer gone before I even touch my actual engineering hours. Unacceptable. The Alternative Landscape (And Why I Picked What I Picked) I went down the rabbit hole. I tested seven different model providers over a long weekend, ran the same prompts through each, compared output quality, latency, and price. Here's the full breakdown I compiled in a spreadsheet (because yes, freelancers absolutely live in spreadsheets): GPT-4o (OpenAI): $2.50 input / $10.00 output per million tokens. The default. The expensive default. GPT-4o-mini (OpenAI): $0.15 input / $0.60 output per million tokens. Already 16.7× cheaper than its big sibling. DeepSeek V4 Flash (Global API): $0.18 input / $0.25 output per million tokens. Forty times cheaper than GPT-4o. Qwen3-32B (G

I built a web front end for an Nmap-based port scanner: a FastAPI backend, a React dashboard, background scan jobs, a plugin system. It worked. Then I sat down and audited it like an attacker would — and found a stack of real weaknesses, plus a lesson in why you verify an exploit before you call it one. This is the honest version: the holes I found, the unauthenticated-RCE chain I thought I had, why it didn't actually fire, and the hardening I shipped anyway. Repo: https://github.com/DipesThapa/PortScanner This is my own project, audited and fixed by me. No third-party systems were touched. Scanners are dual-use — only ever point one at hosts you own or are authorised to test. Hole 1: no authentication, anywhere The foundation: every API route and the /ws/status WebSocket were open. No API key, no session. The Dockerfile bound 0.0.0.0:8000 and ran as root. Anyone who could reach the port could drive scans, hit the upload endpoint, and read every job's logs. api_router = APIRouter () # no dependencies — fully open This is the real, unambiguous problem. Everything below is only interesting because it sat behind no auth. Hole 2: an upload endpoint that allowlisted its own files Deep-dive follow-up commands ran against an allowlist — good instinct. But an upload endpoint wrote a file, chmod +x 'd it, and then added it to that same allowlist: for item in scripts_dir . glob ( " * " ): if item . is_file (): allowed . add ( str ( item . absolute ())) # upload authorises itself An allowlist any input can extend isn't an allowlist. This is a genuine design footgun. Hole 3: the RCE I thought I had — and why it didn't fire Here's the chain I got excited about: the scan target flows toward Nmap's argv, and it's subprocess.run(..., shell=False) . No shell injection — but you don't need a shell to abuse Nmap. If a target became --script=/uploaded.nse , Nmap would load and run that NSE (Lua) script, and NSE can call os.execute . Upload a malicious .nse (Hole 2), get Nmap to load it

Developers love building things. Sometimes the hardest part isn't writing code—it's organizing data. Over the past few months, I've been building a large SVG library containing more than 180,000 vector files. At first, I assumed collecting the files would be the biggest challenge. I was wrong. The real challenge was organizing them. The Duplicate Problem Once a collection reaches hundreds of thousands of files, duplicates become unavoidable. Different sources often contain identical icons with different filenames. For example: facebook.svg facebook-logo.svg facebook-icon.svg facebook-black.svg facebook-circle.svg Some of these are genuine variations. Others are simply duplicates from different icon packs. Automatically detecting the difference isn't always easy. Collections Instead of Files Instead of treating every SVG as an individual page, I decided to build everything around collections. Examples include: Facebook Docker Kubernetes Payment Icons Weather Icons Medical Icons Programming Languages Each collection groups similar SVGs together, making browsing much easier than searching individual files. Keeping Search Engines Happy One interesting problem appeared during development. Should every individual SVG page be indexed? After experimenting with different structures, I chose a different approach. Only complete, content-rich collections are indexed. Individual SVG pages remain accessible but are excluded from search engine indexes. This avoids creating hundreds of thousands of thin pages while allowing search engines to focus on pages that actually provide value. Automation Managing thousands of collections manually isn't realistic. Several background scripts now automate most repetitive tasks: Collection descriptions Meta titles Meta descriptions FAQ generation Sitemap updates Controlled indexing This allows the library to continue growing without requiring manual editing for every collection. Data Cleanup One task I underestimated was cleanup. Large datasets

Multiplayer bugs in Unity rarely look like networking bugs. They look like "the game froze," "the player teleported," or "it worked in the Editor and broke in the WebGL build." By the time you've traced it back to the actual cause, you've usually burned an afternoon. Here are 10 issues that show up constantly in Unity networking code — WebSocket-based, Socket.IO, or otherwise — with the actual root cause and the fix. A few of these come straight out of real regression tests and commit history in socketio-unity , an MIT-licensed Socket.IO v4 client for Unity. The rest are patterns you'll recognize if you've shipped a multiplayer game. 1. Reconnect wipes your room/namespace state Symptom: Connection drops for two seconds, comes back, and the player is no longer in their room/lobby/channel — even though the server never removed them. Cause: A common (bad) reconnect implementation tears down the whole client and rebuilds it from scratch — including the list of channels/namespaces the player had joined. The reconnect "succeeds" at the transport level but silently drops application-level state. Fix: Reconnect logic should preserve subscriptions across the transport reset and only re-emit join / connect for namespaces the client already had open. If you're rebuilding the socket object on every reconnect attempt, stop — reconnect the transport, keep the namespace map. // Wrong: rebuilds everything, loses namespace state void OnReconnect () => CreateFreshEngine (); // Right: reuses the existing namespace map void OnReconnect () => ReconnectEngine (); // _namespaces untouched 2. "get_gameObject can only be called from the main thread" Symptom: Random UnityException thrown from inside a network event handler, but only sometimes — usually right when the server sends something. Cause: Your WebSocket/network library delivers callbacks on its own I/O thread. Any Unity API call ( transform.position = , Instantiate , even some Debug.Log paths) from that thread throws. Fix: Never tou

FCC to let ISPs stop listing all passthrough fees, give single "up to" price.

The industry is described as a "dual-track" race. On one side are incumbents (Big Tech) with massive infrastructure and deep pockets. On the other is a wave of nimble startups specializing in specific engineering, error-correction, and simulation challenges. The sector is currently transitioning beyond the Noisy Intermediate-Scale Quantum (NISQ) era toward fault-tolerant systems and commercial quantum advantage—the point where quantum machines reliably outperform classical supercomputers for useful tasks. These companies are building the foundational cloud-accessible platforms and hardware: Amazon Braket (AWS) IBM Google Quantum AI Microsoft NVIDIA These players are driving innovation in specific qubit modalities or niches: Superconducting Qubits: Rigetti Computing, IQM, and Atlantic Quantum. Trapped Ion: IonQ, Quantinuum, and Alpine Quantum Technologies. Neutral Atom: QuEra, PASQAL, and Atom Computing. Photonic: Xanadu, PsiQuantum, and Quandela. Silicon/CMOS: Diraq and Silicon Quantum Computing. Error Correction: Riverlane and Q-CTRL are focused on the "noise" problem, helping make unstable qubits behave predictably. Software & Algorithms: Classiq (design automation) and Multiverse Computing (finance/optimization applications). Quantum-Safe Cybersecurity: PQShield and evolutionQ are developing cryptographic solutions to protect data against future quantum threats.

Automation is the part of DevOps that actually earns the title. Day 6 was two of the most everyday automation tasks there are, and both had a trap sitting in plain sight. One Linux task, one AWS task. Schedule a recurring job with cron, and launch an EC2 instance from the AWS CLI. The tasks come from the KodeKloud Engineer platform if you want the same lab to work through. Cron: five fields, one rule that trips everyone Cron is the scheduler that has quietly run Linux automation for decades. You hand it a job and a schedule, and its daemon, crond, wakes up every minute to check whether anything is due. If that daemon is not running, nothing fires, so the first move is making sure it is installed and enabled. # Become root sudo su - # Install the cron daemon if it is missing yum install cronie -y # Enable it at boot, start it now, and confirm it is alive systemctl enable crond.service systemctl start crond.service systemctl status crond.service cronie is the package name on RHEL-family distros. enable makes the service survive a reboot, start brings it up right now, and status is how you confirm it is actually running instead of assuming it is. Now edit the crontab: # Edit the current user's crontab crontab -e # minute hour day-of-month month day-of-week command 0 2 * * * /path/to/script.sh # List what is currently scheduled crontab -l That line runs the script every day at 2am. The five fields, in order, are minute, hour, day of month, month, and day of week: minute: 0 to 59 hour: 0 to 23 day of month: 1 to 31 month: 1 to 12 day of week: 0 to 7, where both 0 and 7 mean Sunday Here is the rule that quietly breaks schedules. When you set both the day-of-month field and the day-of-week field to something other than a star, cron treats them as OR, not AND. So 0 0 13 * 5 does not mean midnight on Friday the 13th. It means midnight on every 13th of the month, and also every Friday, whichever lands first. If you actually want the AND, you restrict one field in cron and che

The open-source ecosystem is converging on a hard question: when a commit is written with AI assistance, how do we know — and how do we enforce the disclosure policy? Python's discourse, Linux kernel's Assisted-by trailer, Fedora's AI policy, Apache's disclosure guidelines — every major project is grappling with this. But until now, there has been no tool at the CI level to enforce whatever policy a project chooses. Commit Check v2.11.0 introduces AI Attribution Governance — a new feature that detects known AI tool signatures in commit messages and lets projects decide whether to forbid them outright. To our knowledge, no existing tool enforces this kind of policy at the CI level. The industry need The conversation around AI disclosure is no longer theoretical: The Linux kernel standardized on the Assisted-by: trailer format — but deliberately stopped short of CI enforcement. As Sasha Levin noted at the Maintainers Summit, the kernel sets the convention, not the gate. The Python community is actively discussing whether Claude Code usage should be documented VS Code issue #313962 proposes replacing Co-authored-by with Assisted-by for AI agents Fedora requires AI disclosure (recommends the Assisted-by trailer). QEMU and Gentoo go further and forbid AI-generated contributions entirely. Each community defines its own policy — but none provides a neutral enforcement layer. That is the gap Commit Check fills. Configuration: a single toggle Commit Check keeps it simple. One configuration value, three ways to set it. TOML ( cchk.toml ): [commit] ai_attribution = "forbid" CLI: commit-check --message --ai-attribution = forbid Environment variable: CCHK_AI_ATTRIBUTION = forbid commit-check --message Two modes: Mode Behavior "ignore" No validation (default, backward compatible) "forbid" Rejects any commit containing known AI tool signatures There is no require mode in this release — only ignore and forbid . The reason is pragmatic: requiring an Assisted-by or similar trailer is

Hit a perfect 7-day streak this week, splitting my time between a massive aesthetic pivot in my...

If your Prime Day purchases included a new desk, TV stand, bookshelf, or other furniture you still haven’t assembled, Hoto’s PixelDrive cordless screwdriver can help speed up the process. It’s currently on sale for $59.99 ($20 off) at Amazon, matching its best price to date. From tightening loose screws on furniture to repairing electronics, the […]

submitted by /u/lIlIlIKXKXlIlIl [link] [留言]