OfflineU

Self-hosted course viewer for a local video/audio/text training library. Runs as a single Flask app in Docker, tracks watch progress and notes per lesson, and gives the whole library a dashboard-style home page instead of a bare file browser.

This is a personal deployment, not a public project — this doc is internal reference for running/maintaining it, not a pitch.

Screenshot predates the current theming/icon work — kept for a rough idea of layout, not pixel-accurate.

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Deployment

Deployed via docker-compose.yml, built directly from the Dockerfile in this repo (pull_policy: build, not a registry pull):

services:
  offlineu:
    build: .
    pull_policy: build
    container_name: offlineu
    network_mode: host
    ports:
      - "5000:5000"
    environment:
      - PUID=1000
      - PGID=10
      - TZ=America/New_York
      - FLASK_ENV=production
    volumes:
      - /volume1/files/training:/app/courses   # course library
      - /volume2/docker/offlineu/data:/app/data # settings/progress/notes
    restart: unless-stopped

Auto-deploy: the Gitea repo has a webhook to Dockhand — a push to main triggers a full image rebuild from the Dockerfile (confirmed, not just a container restart), so Dockerfile changes (e.g. adding ffmpeg) take effect on the very next push without any manual step.

Confirming a deploy landed: a plain VERSION file at the repo root (a timestamp + short description, updated by hand alongside each commit) ships into the image via the normal COPY . . and is shown at the bottom of the Settings page and in /health's JSON response, so after a push you can check the running container actually picked it up instead of guessing. Deliberately not derived from git rev-parse at Docker build time - Dockhand's build context doesn't reliably have .git available, which silently produced "unknown" instead of an actual commit. Reads as dev outside Docker (no VERSION file to read, e.g. before the first commit that adds one). CHANGELOG.md at the repo root accumulates that same line on every commit (newest first) instead of overwriting it, and shows as a "What's New" list under the version line in Settings - so you can see recent history, not just the current build.

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Local development

pip install -r requirements.txt
python offlineu_core.py --library-path /path/to/courses --debug

Opens on http://127.0.0.1:5000. ffprobe (from ffmpeg) needs to be on PATH for video-duration lookups to work locally; without it those just silently stay blank instead of erroring.

CLI options

Option	Description
--host	Bind host (default 0.0.0.0)
--port	Bind port (default 5000)
--debug	Enable Flask debug mode
--create-templates	Regenerate default templates if missing
--library-path	Course library root (overrides COURSES_LIBRARY_PATH)
course_path (positional)	Load a specific course directly at startup

Environment variables

Variable	Default	Purpose
COURSES_LIBRARY_PATH	/app/courses	Course library root
OFFLINEU_DATA_DIR	/app/data	Where settings/progress/notes data lives
AUTO_LOAD_COURSE	—	Course path to load automatically on start

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Features

Library browsing

• Lazy-loading folder browser (grid or list view) with search, including an opt-in transcript search across subtitle files
• Course cards show media file count, total video/audio runtime, and completion % at a glance
• Cover art: uses a manually-placed cover/folder/thumbnail/thumb/ poster image if a course has one, otherwise auto-generates one via ffmpeg - samples a few candidate frames from the first several seconds of the course's first video (where an intro title card typically lives) and keeps the one that compresses to the largest JPEG, a cheap proxy for "has the most going on" that favors a title card/logo over a blank fade-in or a plain frame of the presenter
• File Management (/unsorted, its own item ("Files") in the bottom tab bar alongside Home/Notes/Help/Settings): a dedicated page for everything that touches files on disk, since it needs more room than a Settings card and warrants review before anything actually changes.
  • Sort Unsorted: drop new/incoming courses into an Unsorted folder at the library root, then scan proposes a destination for each one by keyword overlap against the existing category tree - read fresh from disk every scan, so it adapts to whatever folders you actually have rather than any hardcoded subject list. Three outcomes per item: a confident match to an existing folder, a suggested new subfolder under a broader category match, or "needs review" (unchecked by default) when nothing overlaps at all. Every row has a folder-picker dropdown (listing every real category in the library, plus "+ Create new folder…") so a wrong or low-confidence guess is one click to correct, and a name field to rename the course's folder in the same move. Creating a new folder means picking its parent from a dropdown and typing just the new folder's own name, with a live "Will create: X/Y" preview so the resulting path is confirmed before applying - the same picker Manage Library's Move action uses. The picker excludes actual course/item folders, not just organizational ones: a leaf folder holding a single non-video/audio file (an ebook, an audiobook in a format this app doesn't play, etc.); a folder whose whole subtree has no video/audio anywhere in it at all (a course's bundled source code, a Python virtualenv, project assets, ...) even though it has plenty of subfolders; and a release-bundle folder that wraps a single real course one level down under its own "course display name" folder, alongside unrelated (possibly empty) junk siblings at the same level - all three cases Library browsing's own course detection wouldn't catch either, since it only checks one level of nesting for video/audio. Nothing on disk moves until you review and hit Apply. Matching ignores common noise (e-learning platform names, release/distribution-group tags, dates) via a stopword list, and beyond that treats a match against a folder's own deliberate name as always stronger evidence than a word only borrowed from a sibling course's title - and among those borrowed words, downweights ones that recur across many categories (a prolific creator's name, etc.) so they can't outvote a genuinely specific word just by sharing more of them.
  • Refresh Library: manually bypasses the 5-minute filesystem-scan cache (this now includes the category tree Sort Unsorted/Manage Library's picker builds - previously rebuilt on every page load, a full, uncached walk of the whole library that got noticeably slow over a NAS-mounted (SMB) library as the course count grew), for when files were added/removed directly on disk.
  • Bulk Rename: find & replace across every course/folder name in the library at once, with a per-match preview and the ability to drop individual matches before applying. Three match modes: plain text (default, literal substring), wildcard (shell-style */?, e.g. .BOOKWARE* catches .BOOKWARE-GETH, .BOOKWARE-BOOKTIME, .BOOKWARE-BLZiSO, etc. in one pass), or full regex (with backreferences in the replacement, e.g. \1).
  • Manage Library: hide courses/folders from the browser without touching anything on disk (hiding a folder hides everything inside it; bulk-select elsewhere to hide or queue several at once), rename a course/folder in place, or move one anywhere else in the library via the same folder-picker/create-new-folder UI Sort Unsorted uses - handy for correcting a bad auto-sort later or just reorganizing. A search box finds any course/folder by name anywhere in the tree instead of expanding levels one by one (results get the same Move/Rename/Hide actions, just without an expand arrow, since a hit is somewhere specific rather than a level to browse into); every row also has a checkbox, so several items - found via search or expanded across different tree levels - can be hidden, shown, or moved to the same destination together in one batch instead of one at a time.
  • Undo: a "Last action: ... [Undo]" bar appears after any move or rename (Sort Unsorted apply, Bulk Rename apply, a Manage Library move/rename, a bulk move) and reverses the whole batch in one click. Only ever covers move/rename - hiding is already a one-click toggle with nothing to undo, and Delete is permanent by design, so it's deliberately never in this history no matter how "undo" gets framed. Re-checks each item before reversing it (the original spot may have been reused since), so a partial batch failure reports exactly what did and didn't reverse rather than silently doing nothing.
  • Duplicate Courses: scans every course in the library (Unsorted included) for names that look like the same thing filed twice, using the same tokenizer as Sort Unsorted so a platform-name or release-tag difference doesn't hide a real duplicate. Groups by similarity (union of any two courses over the threshold, transitively) rather than showing raw pairs; each course in a group gets a one-click Hide, or a Delete that permanently removes it from disk (the one destructive action in the whole app - confirmed with the full path before it runs). A group can also be marked "Not a duplicate" if the match is wrong, which excludes that specific pair from future scans without touching anything else that happens to match one of those courses; ignored pairs are listed (and reversible) under "Ignored matches," and persist through backup/restore alongside hidden paths and Next Up. (Matching is deliberately scoped to whole course folders, not individual lesson files - courses that split one topic across several numbered files, e.g. "...Part 1"/"...Part 2", look just as similar by name as a genuine re-download, so file-level matching wasn't reliable enough to keep.)
  • Clean Up Stale References: finds entries in the hidden-paths list, Next Up queue, Favorites, or Recently Viewed history that point at a path no longer on disk - normally from renaming/moving/deleting a course directly on the NAS instead of through the app (doing it through the app already keeps these in sync). Review individually or clear them all at once; course files themselves are never touched.
  • Storage Usage: disk usage per top-level library folder, largest first, with a simple proportional bar per entry - manually triggered (it reads every file's size) rather than run automatically. Click any folder row to drill into its own contents one level at a time, with a Back button to climb back out.

Dashboard

• Library-wide stats (courses, lessons completed, time watched, time remaining, day streak) and a 90-day activity heatmap
• Favorites — star any course from its list row or its own page for quick access from the dashboard, independent of recency or curated queues
• Next Up queue (manually curated, reorderable)
• Pick Back Up (courses with progress that have gone stale)
• Recently Added / Recently Viewed
• Surprise Me — dice icon in the header, random pick weighted toward incomplete courses
• Grid view shows a small progress ring in the corner of each course's thumbnail (a checkmark once complete) instead of a separate bar, so completion reads at a glance without switching to list view
• Interface polish: a shorter header (matching every other page instead of standing out taller), Files moved before Settings in the bottom nav, a visible focus ring for keyboard navigation, and a redundant course-name badge removed from the header (the course name is already the page's own heading right below it)

Playback & progress

• Video/audio player with resize, playback-speed presets, and resume-from- last-position
• Course outline sidebar on the lesson page (left side): every section and lesson in the course (videos and documents alike - a standalone PDF/doc is its own entry, same as a video), one click to jump anywhere without backing out to the course page first. The current lesson's section opens automatically and scrolls into view; sticky and independently scrollable on desktop, stacks below the player on narrow viewports. Collapsible to a slim rail (remembered per device) for a full-width player, and which sections you've manually expanded is remembered too, so re-opening a course doesn't reset everything back to collapsed. Shares its rendering with the loaded-course dashboard view (templates/ _course_tree.html), so the two always look and behave the same.
• Auto-play next lesson when one ends, with a cancelable few-second countdown - on by default, toggle it off in Settings → Video Player
• Keyboard shortcuts on the lesson page: Space (play/pause), ←/→ (seek 10s), ↑/↓ (volume), ,/. (step playback speed), [/] (previous/next lesson), F (fullscreen), N (quick-capture a note) - see Help for the full list
• Auto-tracks watch progress and completion per lesson
• Video/audio durations read via ffprobe and cached persistently per course (.offlineu_duration_cache.json), so total runtime and per-lesson length show up before you've ever pressed play — not just after; the same cache backs the library-wide "time remaining" stat
• Settings → "Precompute Lengths & Cover Art" walks the whole library in the background to populate durations and thumbnails up front, with live progress
• Settings → "Regenerate Thumbnails" deletes and re-runs auto-generated cover art for every course that has one (manually-placed covers are never touched) - the only way to pick up an improvement to how thumbnails are picked on courses whose thumbnail was already cached under the old logic, since it's otherwise served from disk forever

Notes

• Timestamped notes per lesson, capturable via a keyboard shortcut without leaving the player
• Notes Hub: every note across the whole library, searchable, in one list
• Per-course study guide export (markdown, organized by section)

Personalization (Settings)

• 46 built-in themes (grouped in the dropdown: Base, Editor Themes, and 5 categories of website-inspired schemes sourced from Figma's "53 Unique Website Color Schemes" - 34 of the 53 kept, all as dark/colored backgrounds rather than the source page's mostly-white mockups, after cutting a couple of neon-bright accents and pruning near-duplicates by actual color distance), or a fully custom accent color, corner radius, and card style
• Font, text size, page width, and spacing density
• Default library path override (Refresh Library and Bulk Rename live on the File Management page - see above)

Backup & integrations

• One-click backup export and restore: settings, hidden-path choices, the Next Up queue, Favorites, recent-view history, ignored-duplicate pairs, Outline config, and every course's progress/notes as a zip (not the course files themselves). Restore overwrites current data and needs a matching course folder to already exist for each course's progress to land - it's a "put my data back" action, not a merge
• Optional Outline integration — push a lesson's notes to an Outline document/collection

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Data files

Everything under OFFLINEU_DATA_DIR (app-wide, not tied to a course):

File	Contents
settings.json	Theme, layout, library path, etc.
hidden_paths.json	Courses/folders curated out of the browser
next_up.json	The Next Up queue, in order
favorites.json	Favorited course paths
recent_views.json	Cross-course "Recently Viewed" history
ignored_duplicates.json	Course-path pairs confirmed not duplicates
outline_config.json	Outline API token/collection mapping

Per-course, written inside the course's own folder on the library volume:

File	Contents
.offlineu_progress.json	Per-lesson completed/progress/duration/notes
.offlineu_duration_cache.json	ffprobe duration cache, keyed by (path, size, mtime)
.offlineu_thumbnail.jpg	Auto-generated cover art (only if no manual cover exists)

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Folder structure example

MyCourse/
├── Section 1/
│   ├── 01 - Intro.mp4
│   ├── 02 - Setup Guide.pdf
│   └── 03 - Quiz.html
├── Section 2/
│   ├── 04 - Advanced Tips.mp4
│   └── resources/
│       └── extras.md
├── .offlineu_progress.json        ← created automatically
├── .offlineu_duration_cache.json  ← created automatically
└── .offlineu_thumbnail.jpg        ← created automatically, only if no manual cover exists

No metadata files needed — course/section/lesson names come straight from folder and file names.

An Unsorted/ folder at the library root (alongside the real category folders) is the drop point for new/incoming courses — see Sort Unsorted above.

Supported file types

Type	Extensions
Video	.mp4 .mkv .avi .mov .webm .m4v .flv .wmv
Audio	.mp3 .wav .m4a .aac .ogg .flac
Documents	.txt .md .html .htm .pdf .docx .doc .rtf
Subtitles	.srt .vtt .ass .sub .sbv
Quizzes	Any doc file whose name contains quiz, exam, test, assessment, exercise, assignment, or homework

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Tools

tools/generate_website_scheme_themes.py is the one-off script that produced the 34 "website scheme" theme entries in THEME_PALETTES (of 53 candidates - all 24 light-mode ones were converted to dark/colored backgrounds per request, then 19 were cut across two review passes: 2 for a neon-bright accent, 17 for landing too close to another kept scheme once mapped into actual UI colors, since forcing everything dark made several collide that hadn't before) - not part of the running app, kept for reference if those palettes ever need regenerating or extending. build_theme() takes a force_mood='dark'|'light' override for exactly this kind of bulk remapping. See its module docstring for how it turned Figma's color-scheme screenshots into actual UI palettes.