Skip to content
yceffort
PostsSeriesTagsAbout🧪 Research
KO

Tweaks

theme
accent palette
film grain
minimal mode
05 POSTS

Networking 1

  • â—† OG Scraping Server Design Notes · Part 2
    #security#nodejs#backend

    Building an OG Scraping Server in Node.js (2): How SSRF Gets Through

    A feature where the server opens a URL the user handed it has the textbook conditions for SSRF written into its spec. Six ways a whitelist gets bypassed first, then five defensive principles that block them, all actually run on Node. Strip IPv4-mapped by hand and it gets through in hex notation, undici lookup hook is never called when the host is an IP literal, and URL.hostname keeps the brackets on an IPv6 literal. The final post of a two-part design note on OG scraping servers.

    2026-08-22·25 min read
  • â—† OG Scraping Server Design Notes · Part 1
    #web-scraping#backend#nodejs

    Building an OG Scraping Server in Node.js (1): From Runtime Choice to Error Rate and Latency

    The "10% error rate" of a link preview server is a single number that five different kinds of failure got mashed into. This post works out why this workload is I/O bound at that TPS, where runtime choice actually diverges across four points, and then moves on to lowering the error rate with User-Agent and encoding. Node built-in TextDecoder turns CP949 extension characters into different characters without raising an error, and a scraped og:title is not an API response but user input. It also covers cache stampedes, negative caching, and a two-million-run simulation that verifies "P95 under one second" by working backwards from the cache hit rate. The first post of a two-part design note on OG scraping servers.

    2026-08-22·33 min read
  • â—† Kubernetes for Frontend Developers · Part 4
    #kubernetes#devops#debugging

    How Do Pods Terminate? Measuring the Causes and Fixes of Deploy-Time Errors

    Even a deploy that changes not a single line of code leaks errors. This is a measured record of tagging every failure that leaks during rolling deploys by type and timestamp, performing an autopsy on four causes, and stacking prescriptions one layer at a time until the count reaches zero. Includes the actual Next.js shutdown code, hostage draining, and the real CrashLoopBackOff timetable. Part 4 of the Kubernetes for frontend developers series.

    2026-08-08·Updated 2026-08-09·20 min read
  • â—† Kubernetes for Frontend Developers · Part 3
    #kubernetes#networking#devops

    How Does Traffic Reach My Pod? From ClusterIP to port-forward

    A Service's ClusterIP is an IP attached to no machine, yet curl reaches it. iptables rules and conntrack, EndpointSlice, cluster DNS and ndots, Gateway, and port-forward: a record of opening up the entire path a request takes to a pod, directly in a kind cluster. Part 3 of the Kubernetes for frontend developers series.

    2026-08-06·27 min read
  • â—† Directive Deep Dive · Part 2
    #react#nextjs#networking

    React Server Functions Deep Dive: To the End of "use server"

    What happens behind a single line of "use server"?

    2026-03-09·26 min read
mailMail icongithubtwitter
yceffort
•
© 2026
•
https://yceffort.kr