Downloader

A cross-browser Manifest V3 extension that hands download links and detected media to the Downloader desktop app.

Features

• Context menu — right-click a link, image, video or audio → “Download with Downloader”. Right-click a text selection → “Download selected links with Downloader”.
• Popup — paste a link, send the detected media for the current tab, or scan the page for downloadable links, then send one or all to the app.
• Media capture — watches network responses and surfaces video / audio / HLS (.m3u8) streams, with a badge count on the toolbar icon.
• Size, resolution and quality picker — each detected item is probed for its file size, and an HLS master playlist expands into a quality dropdown (resolution or bitrate per option) instead of one opaque .m3u8 row. Probing never blocks the popup: it renders immediately, then upgrades rows in place as results arrive.
• Main media vs. Other detected — on media-heavy pages (a social-media post with dozens of segment/thumbnail requests) the video you're actually viewing is promoted to a Main media section; everything else collapses into an expandable Other detected (N) — nothing is hidden, just triaged.
• Known-unsupported-site message — on sites that stream via MSE/DRM with no fetchable file URL (YouTube, Netflix, …), the popup explains why nothing was found instead of showing a blank list that looks broken.
• Auto-send — every captured link is forwarded to the app's local listener. By default it is added silently and starts downloading (the app's /api/add endpoint); untick “Add silently (no dialog)” in the popup to review each link in the app's Add dialog (/add?url=…) instead. On an app version without the API the extension falls back to the dialog automatically.
• Signed-in session hand-off — when you send a link, the extension also passes the cookies for that one URL to the app, so a site that needs you to be logged in (e.g. a YouTube video handled by the app's video downloader) can be fetched with your live session. Cookies are read only for the URL you send, go only to your local app, are never logged, and the app deletes them right after the download. See PRIVACY.md.

Direct media capture doesn't work on DRM/encrypted streaming sites (Netflix, and YouTube's in-page player) — they don't expose a fetchable media URL. A YouTube video page link can still be sent to the app, which downloads it via its video-site plugin (using the session cookies above when the video requires sign-in).

Requirements

1. The Downloader desktop app must be running.
2. Settings → Browser extension & local API must be on in the app (it opens the local listener on port 15151, falling back to 15152–15155 if that port is taken by another program — the extension finds the right one automatically). It is enabled by default; the effective address is shown in the app's Settings.

Load it for testing (unpacked)

Chrome / Edge

1. Go to chrome://extensions (or edge://extensions).
2. Turn on Developer mode.
3. Load unpacked → select this browser-extension folder.

Firefox

1. Copy manifest.firefox.json over manifest.json (Firefox reads manifest.json):

   cp manifest.firefox.json manifest.json
   

   (Keep a backup of the Chrome manifest.json — they differ only in the background shape and the Firefox browser_specific_settings block.)
2. Go to about:debugging#/runtime/this-firefox → Load Temporary Add-on → pick manifest.json.

How it talks to the app

The extension only needs the app's loopback endpoints:

GET http://127.0.0.1:<port>/api/add?url=<url-encoded link>   # silent add (default)
GET http://127.0.0.1:<port>/add?url=<url-encoded link>       # open the Add dialog instead
GET http://127.0.0.1:<port>/ping                              # reachability check

<port> is normally 15151; if another program holds it, the app falls back within the declared range 15151–15155 and the extension probes /ping across that range (last-known-good port first) to rediscover it. These are served by Services/LocalApiService.cs in the desktop app (see docs/local-api.md in the main repo for the full API). No other ports, servers or accounts are involved.

Files

File	Role
manifest.json	Chrome/Edge MV3 manifest (service-worker background)
manifest.firefox.json	Firefox MV3 manifest (scripts background + gecko id)
common.js	Shared helpers: media detection, sendToApp(), size/HLS probing, grouping
background.js	Context menus, response sniffing, badge, message handler, probing coordinator
content.js	Tracks the visible/playing <video>/<audio> element for Main-vs-Other triage
popup.html / popup.css / popup.js	Toolbar popup UI (grouped cards, quality picker)
icons/	Toolbar/store icons (16/48/128)

Run the unit tests (pure helpers in common.js) with node --test src/browser-extension/common.test.js.

Publishing (later)

Store submission needs the author's developer accounts and is not done here:

• Chrome Web Store / Edge Add-ons — zip this folder and upload in the respective dashboards.
• Firefox (AMO) — submit the Firefox-manifest build at addons.mozilla.org.

Bump version in both manifests for each release.