[{"data":1,"prerenderedAt":284},["ShallowReactive",2],{"api:\u002Fapi\u002Fconfig:en":3,"api:\u002Fapi\u002Fprofile:":8,"api:\u002Fapi\u002Fcategories:en":19,"api:\u002Fapi\u002Fprojects\u002Fledger-core:en":177,"api:\u002Fapi\u002Fnotes:en":232},{"email":4,"lang":5,"name":6,"role":7},"djrciv@gmail.com","en","Ewsirdev","Web developer: websites, landing pages and Go services",{"name":6,"handle":6,"contacts":9,"note":18},{"email":10,"github":12,"telegram":15},{"url":11,"label":4},"mailto:djrciv@gmail.com",{"url":13,"label":14},"https:\u002F\u002Fgithub.com\u002Fewsir247","github.com\u002Fewsir247",{"url":16,"label":17},"https:\u002F\u002Ft.me\u002FEwsirdev","@Ewsirdev","Contacts: Telegram, GitHub, email. This file is the single source of contacts for the site, the contact block, JSON-LD sameAs, security.txt and llms.txt.",[20,49,80,108,144],{"slug":21,"title":22,"blurb":23,"variant":24,"palette":25,"layout":26,"count":27,"preview":28,"stack":44},"landings","Landing pages","One page, one job. Hand-written markup where possible, plus one WebGL experiment.","drop","ice","shots",6,[29,34,39],{"slug":30,"title":31,"shot":32,"hue":33},"landing-studio","Halftone: lighting studio","\u002Fshots\u002Flanding-studio-desktop-sm.webp",212,{"slug":35,"title":36,"shot":37,"hue":38},"landing-saas","Kill Switch: subscription tracker","\u002Fshots\u002Flanding-saas-desktop-sm.webp",182,{"slug":40,"title":41,"shot":42,"hue":43},"landing-event","Small Scale: conference","\u002Fshots\u002Flanding-event-desktop-sm.webp",124,[45,46,47,48],"CSS","HTML","GitHub Actions","JS",{"slug":50,"title":51,"blurb":52,"variant":53,"palette":54,"layout":55,"count":56,"langs":57,"preview":61,"stack":77},"sites","Multi-page sites","Sites with their own structure, routing and forms: from a client project to a set of niche pages.","merge","violet","frames",8,[58],{"lang":59,"count":60},"TypeScript",5,[62,67,72],{"slug":63,"title":64,"shot":65,"hue":66},"legal-multipage-site","Multi-page legal services website","\u002Fshots\u002Flegal-multipage-site-desktop-sm.webp",250,{"slug":68,"title":69,"shot":70,"hue":71},"niche-landings","Catalog of 10 niche demo landing pages","\u002Fshots\u002Fniche-landings-desktop-sm.webp",32,{"slug":73,"title":74,"shot":75,"hue":76},"docs-engine","Sverlo: a documentation generator in Node.js","\u002Fshots\u002Fdocs-engine-desktop-sm.webp",25,[47,59,78,79],"Cloudflare Pages","axe",{"slug":81,"title":82,"blurb":83,"variant":84,"palette":85,"layout":86,"count":27,"langs":87,"preview":90,"stack":105},"apps","Web apps","Apps you use: with a server, auth and e-mail, or offline-first PWAs where the data stays in the browser.","torus","mint","phone",[88],{"lang":59,"count":89},4,[91,96,101],{"slug":92,"title":93,"shot":94,"hue":95},"bad-club-booking-app","Bad Club: seat booking for a gaming coworking space","\u002Fshots\u002Fbad-club-booking-app-desktop-sm.webp",150,{"slug":97,"title":98,"shot":99,"hue":100},"typing-lab","typing-lab: a touch-typing trainer","\u002Fshots\u002Ftyping-lab-desktop-sm.webp",45,{"slug":102,"title":103,"shot":104,"hue":100},"budget-split","budget-split: shared expense tracker","\u002Fshots\u002Fbudget-split-desktop-sm.webp",[59,106,79,107],"Vite","vitest",{"slug":109,"title":110,"blurb":111,"variant":112,"palette":113,"layout":114,"count":115,"langs":116,"preview":125,"stack":141},"backend","Backends","Services with an API, a database and tests: in Go, Rust, Python and TypeScript. A language filter sits inside the section.","crystal","steel","list",24,[117,120,122,124],{"lang":118,"count":119},"Go",12,{"lang":121,"count":89},"Python",{"lang":123,"count":89},"Rust",{"lang":59,"count":89},[126,131,136],{"slug":127,"title":128,"shot":129,"hue":130},"kanban-tasks","Amber: kanban board","\u002Fshots\u002Fkanban-tasks-desktop-sm.webp",344,{"slug":132,"title":133,"shot":134,"hue":135},"link-shortener","Short: link shortener","\u002Fshots\u002Flink-shortener-desktop-sm.webp",111,{"slug":137,"title":138,"shot":139,"hue":140},"booking-slots","Appointment booking","\u002Fshots\u002Fbooking-slots-desktop-sm.webp",65,[142,47,143,118],"Docker","SQLite",{"slug":145,"title":146,"blurb":147,"variant":148,"palette":149,"layout":150,"count":27,"langs":151,"preview":158,"stack":174},"cli","CLI tools","Terminal programs: one binary, clear flags, an exit code you can check in a script.","swarm","champagne","terminal",[152,154,156,157],{"lang":118,"count":153},3,{"lang":121,"count":155},1,{"lang":123,"count":155},{"lang":59,"count":155},[159,164,169],{"slug":160,"title":161,"shot":162,"hue":163},"gitpulse","GitPulse: git repository analytics","\u002Fshots\u002Fgitpulse-desktop-sm.webp",7,{"slug":165,"title":166,"shot":167,"hue":168},"logslice","logslice: log analysis with no dependencies","\u002Fshots\u002Flogslice-desktop-sm.webp",160,{"slug":170,"title":171,"shot":172,"hue":173},"envguard","envguard: a linter and a safe for .env files","\u002Fshots\u002Fenvguard-desktop-sm.webp",35,[47,175,142,176],"CLI","stdlib only",{"slug":178,"title":179,"type":109,"category":109,"lang":123,"live_url":180,"stack":181,"description":188,"highlights":189,"run":194,"hue":195,"og":196,"shots":197,"case":205,"case_lang":5,"prev":226,"next":229},"ledger-core","ledger-core: double entry and a hash-chained journal","https:\u002F\u002Fledger-core.ewsir.space",[123,182,143,183,184,185,186,142,187,47],"axum","SHA-256","proptest","musl","distroless","cargo-audit","A double-entry accounting core in Rust: accounts, postings, an immutable journal with a hash chain, an integrity check and a trial balance. Money is integers only (i64, minor units), a transaction sums to exactly 0, arithmetic is checked. Each record stores prev_hash and a SHA-256 of its fields; GET \u002Fv1\u002Fverify recomputes the chain and names the tampered record. Idempotent by Idempotency-Key.",[190,191,192,193],"The posting invariant: lines sum to 0, 2 to 100 lines, one currency; overflow gives 422, not a panic","The hash chain: any change to an amount, memo or account is caught and the tampered record is named","19 tests, property tests: a posting and the balance of all accounts always sum to 0","An 11.4 MB image; 3.5 MiB idle and 4.5 MiB after 200 requests, the chain stayed intact","cd ledger-core && cargo run --release",52,"\u002Fog\u002Fen\u002Fledger-core.jpg",{"desktop":198,"desktop_sm":199,"mobile":200,"dw":201,"dh":202,"mw":203,"mh":204},"\u002Fshots\u002Fledger-core-desktop.webp","\u002Fshots\u002Fledger-core-desktop-sm.webp","\u002Fshots\u002Fledger-core-mobile.webp",1280,800,390,844,{"about":206,"features":209,"run":216,"notes":221},[207,208],"The task: show how to keep accounting invariants at the service level rather than \"hoping the client behaves\": money without floats, a posting that always nets to zero, a journal that cannot be quietly rewritten.","The solution: Rust (axum + SQLite). Amounts are i64 in minor units, arithmetic is checked; every record stores prev_hash and a SHA-256 over all its fields with length prefixes, and GET \u002Fv1\u002Fverify recomputes the chain and names the tampered record. SQLite triggers forbid UPDATE and DELETE.",[210,211,212,213,214,215],"The posting invariant: lines sum to exactly 0, 2 to 100 lines, zero amounts forbidden, one currency; overflow gives 422, not a panic","Idempotency by Idempotency-Key: the same key and body return the original record, a different body gives 409","The hash chain and \u002Fv1\u002Fverify: numbering continuity, prev_hash and a recomputed hash of every record","A trial balance; the debit and credit totals must match","19 tests; property tests: a posting always sums to 0, any change to an amount, memo or account is caught and points at the right record","Result: an 11.4 MB image, 3.5 MiB idle and 4.5 MiB after 200 requests (100 parallel postings and 100 reads), the chain stayed intact",[217,218,219,220],"git clone \u003Crepository on request> ledger-core","cd ledger-core","DEMO_SEED=1 cargo run --release","# http:\u002F\u002Flocalhost:8115",[222,223,224,225],"The chain catches an edit or deletion in the middle but not tail truncation: head_hash has to be stored outside.","Whoever has the database file can drop the triggers: the defence is the chain check.","Numbers above 2^53 lose precision in JavaScript clients; there is no reversal entity.","The project runs on a small VPS with demo data: no redundancy or backups.",{"slug":227,"title":228},"flag-store","flag-store: feature flags with percentage rollout",{"slug":230,"title":231},"csv-doctor","csv-doctor: CSV profiling and cleaning",[233,240,244,249,254,259,264,269,274,279],{"slug":234,"lang":5,"title":235,"date":236,"summary":237,"project":238,"minutes":239},"csp-no-inline-nuxt","CSP without inline scripts: what had to be switched off in Nuxt","2026-10-30","Why a strict script-src self policy breaks static Nuxt, which three steps made the site compatible, and the build check that keeps it so.","landscape-bureau-nuxt",2,{"slug":241,"lang":5,"title":242,"date":236,"summary":243,"project":178,"minutes":239},"hash-chain-tail-truncation","A hash-chained journal: what it catches and what it does not","How ledger-core builds a SHA-256 chain and checks it through \u002Fv1\u002Fverify, why tampering in the middle shows but tail truncation does not.",{"slug":245,"lang":5,"title":246,"date":236,"summary":247,"project":248,"minutes":239},"qr-from-scratch","A QR code from scratch: Reed-Solomon, masks and proving it right","How a zero-dependency QR encoder in TypeScript is built, and four independent ways to check that the matrix is correct.","qr-svg",{"slug":250,"lang":5,"title":251,"date":236,"summary":252,"project":253,"minutes":239},"sm2-day-boundaries","SM-2 and day boundaries: why the schedule is stored as dates","How flashcards-sm2 and habit-tracker avoid shifts from time zones and daylight saving: dates instead of timestamps and a movable day boundary.","flashcards-sm2",{"slug":255,"lang":5,"title":256,"date":236,"summary":257,"project":258,"minutes":239},"ssrf-after-dns","SSRF in webhooks: checking the address after DNS","Why a webhook delivery service checks the addresses after DNS resolution, not the URL string, and how hook-relay connects to the very address it checked.","hook-relay",{"slug":260,"lang":5,"title":261,"date":236,"summary":262,"project":263,"minutes":239},"token-bucket-integers","A token bucket on integers: what property tests check","How rate-gate computes a token bucket without floats, why milli-tokens, and which three properties the proptest property tests prove.","rate-gate",{"slug":265,"lang":5,"title":266,"date":267,"summary":268,"project":137,"minutes":155},"double-booking","Double booking: a transaction plus a partial UNIQUE index","2026-10-20","How booking-slots protects against two clients booking the same time at once, and how that protection is tested.",{"slug":270,"lang":5,"title":271,"date":267,"summary":272,"project":273,"minutes":239},"lease-and-fencing","Lease and fencing: how a queue neither loses a job nor lets a zombie finish it twice","A worker can crash, stall, or wake up after its job was taken by someone else. How the lease and the lease token in job-queue deal with that on SQLite.","job-queue",{"slug":275,"lang":5,"title":276,"date":267,"summary":277,"project":278,"minutes":239},"p95-nearest-rank","p95 in an uptime monitor: the nearest-rank method and what it does not hide","How uptime-monitor computes p50\u002Fp95 latency and uptime, why the nearest-rank method was chosen, and where those numbers can mislead.","uptime-monitor",{"slug":280,"lang":5,"title":281,"date":267,"summary":282,"project":283,"minutes":239},"websocket-from-scratch","WebSocket on the standard library: what really happens under new WebSocket()","Why realtime-rooms has its own RFC 6455 layer, which protocol violations it checks, and why a library is still the better choice for production.","realtime-rooms",1793371809330]