instaarchive-viewer/CLAUDE.md

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

InstaArchive Viewer is a React 19 + Vite 6 PWA for browsing archived Instagram data (official Instagram exports and Instaloader archives). All archive parsing happens client-side in the browser; the Express backend only indexes and serves files from disk, and never parses archive contents.

Commands

• npm install — install dependencies
• npm run dev — Vite dev server on port 3000 (proxies /api and /archives to http://localhost:3001)
• npm run server — Express backend (tsx server.ts) on port 3001, serving ARCHIVES_DIR (defaults to ./_sample-archives)
• npm run build — frontend to dist/, backend to dist-server/
• npm run lint — type-check only (tsc --noEmit)
• npm test / npm run test:watch — vitest
• npx vitest run src/lib/archive-patterns.test.ts — a single test file
• npm run jd2 -- --archives <dir> --dry-run — generate JDownloader .crawljob files for every profile on disk (see scripts/jd2-sync.ts and docs/jdownloader.md)

Local development usually needs both npm run dev and npm run server. Local-folder mode works without the backend; server-mode archives do not.

Architecture

Two archive sources, one data model

Loading is unified behind the ArchiveFile interface (src/types/index.ts, implementations in src/lib/archive-files.ts):

• LocalArchiveFile — wraps a browser File. createObjectUrl() mints a disk-backed blob URL directly from the File; never route media through arrayBuffer(), which pulls whole files into memory.
• RemoteArchiveFile — wraps a file served from /archives/..., fetched on demand.

revocable tells callers whether the returned URL must be revoked. The scanner tracks every minted URL and releases them on archive teardown.

Sidecar directories

An archive root holds one directory per profile plus sidecars that belong to it:

4utumn07                                 -> posts (base)
4utumn07 - reels                         -> reels
story - 4utumn07                         -> stories
story highlights - 4utumn07 - Sunstory   -> highlight "Sunstory"

src/lib/archive-grouping.ts (shared by server and tests) folds these into a single profile with a sources list. Sidecars never appear as standalone archives. Each file the server returns carries its kind, so the client routes posts / reels / story ring / highlight circles without re-deriving naming rules.

Server-side archive index (src/lib/archive-index.ts)

Do not reintroduce per-request filesystem walks. Archives typically live on network storage where per-file stat costs ~1.4ms and does not parallelise; a naive walk of a 110k-file root took ~52s per listing. Instead:

• Each source directory is indexed once and cached, keyed by its directory mtime (a directory stat is effectively free).
• The index is warmed in the background at startup and persisted to CACHE_DIR (mount a volume at /cache).
• GET /api/archives does no file walking at all — it returns directory-mtime signatures, which the client uses for cache invalidation instead of a file count.
• Only media files are stat'd (for size, which gates thumbnailing) and only highlights need mtime (their filenames carry no date).

Scanning pipeline (src/hooks/useArchiveScanner.ts)

handleFiles indexes files, detects format, then parses via one of three largely independent paths that all write into a shared postsMap:

1. JSON manifest (posts_1.json, possibly .json.xz via xz-decompress) — media matched to entries by URI, then ID, then filename heuristic, in that fallback order.
2. Filename patterns — see src/lib/archive-patterns.ts for the export / Instaloader / highlight regexes, extracted as pure functions and covered by tests. Prefer changing them there.
3. Generic grouping fallback — when nothing else matched, files sharing a basename become one carousel.

Results are cached to IndexedDB. Media records store a stable path; url is not persistable for local archives because blob URLs die with the document.

Cache and local-archive persistence (src/lib/archive-cache.ts)

IndexedDB keys are namespaced (archive:, thumb:, handle:) so listing archives does not deserialize every cached thumbnail blob, and thumbnails are scoped per archive to avoid cross-archive collisions.

Restoring an archive rehydrates URLs from path: server archives rebuild HTTP URLs; local archives re-open a persisted FileSystemDirectoryHandle and mint fresh blob URLs. If the folder is unreachable (permission lapsed, or the browser lacks showDirectoryPicker — Firefox/Safari), the app re-prompts rather than rendering broken images.

Thumbnails (src/hooks/useThumbnailQueue.ts + src/lib/thumbnail-worker.ts)

Images over 1MiB are downscaled in a Web Worker via OffscreenCanvas. The queue is serial on purpose — decoding several 50MP+ images at once OOMs the tab. requestThumbnail must keep a stable identity (it reads cache state through a ref), or every completed thumbnail re-runs the effect in all mounted thumbnails.

URL state (src/App.tsx, src/lib/routing.ts)

Paths mirror Instagram: /<archive>/, /<archive>/reels/, /<archive>/p/<shortcode>/. The old ?a=&t=&p= form is still parsed for existing links but never written. Reserved prefixes (api, archives, assets…) can't be mistaken for a profile name.

A post URL carries no tab, as on Instagram — the tab is re-derived from the post's source, so a reel link lands on the Reels tab and pages through reels. Sidecar posts keep directory-scoped ids internally but expose only the shortcode.

Three rules, all learned from real bugs:

• The initial route is captured into a ref on first render; the URL is rewritten from state as soon as anything loads, so reading window.location later sees the rewrite, not the user's link.
• URL writing is gated on hasInitialLoaded, otherwise it erases the deep link before the loader consumes it.
• Deep-link resolution waits on the archive fetch having settled (archivesFetched), not on isServerMode, which is still false while the request is in flight.

Mobile feed (src/components/PostFeed.tsx)

Below md, opening a post renders a scrolling feed page rather than the modal (useIsMobile decides). Only a window of posts is mounted; it grows both ways, and prepending corrects scrollTop in a useLayoutEffect so content doesn't jump. Only the post crossing the viewport centre plays its video and drives the URL. Desktop keeps PostModal; both share MediaCarousel.

Backend (server.ts)

Serves /api/archives, /api/archives/:name/files, static /archives, and the built SPA. Notes:

• Express decodes route params after segment matching, so ..%2f reaches the handler as ../. All user-supplied archive names go through resolveArchivePath.
• Sets CSP and related security headers. The CSP allows blob:/data: for media and unsafe-inline styles (the animation library sets inline styles); scripts stay same-origin only.
• os.userInfo() throws for a UID with no /etc/passwd entry, which is what --user 1234:1234 produces — use describeUser().

Deployment

Container runs as non-root. The image defaults to node, but the archive share must be listable by that UID — a mode-711 share owned by another account needs user: "<uid>:<gid>" in compose. Mount a volume at /cache so the index survives restarts.

PWA / build quirks

• vite.config.ts sets hmr: process.env.DISABLE_HMR !== 'true' — intentional, leave it.
• workbox.navigateFallbackDenylist excludes /api and /archives so those hit the real server.
• Fonts and icons are vendored in public/ — do not reintroduce CDN references; the app advertises offline support and local-only processing.