primedl — Browser Extension

Stream detection and cookie relay extension for the primedl downloader.

What it does

• Detects HLS (.m3u8), DASH (.mpd), HDS (.f4m), MSS (.ism/manifest) streams on any webpage
• Detects direct media files: MP4, TS, WebM, AAC, MP3, OGG, and more
• Detects subtitle files: VTT, SRT, TTML, DFXP
• Captures cookies, User-Agent, Referer and other headers automatically
• Forwards detected streams + cookies to the local primedl Rust app via WebSocket
• Assembles ready-made CLI commands for yt-dlp, FFmpeg, Streamlink, hlsdl, N_m3u8DL-RE
• Supports custom file extensions and Content-Type headers
• URL blacklist, per-tab / session / previous-session views

Supported browsers

Browser	Manifest	Status
Firefox 89+	MV2	✅ Fully supported
Chrome / Brave / Edge 99+	MV3	✅ Supported

How it connects to primedl

When the primedl desktop app is running, the extension sends detected streams to it over a local WebSocket connection (ws://127.0.0.1:7421 by default). The Rust app handles all downloading — the extension only sniffs and relays.

The popup shows a ● primedl connected / ○ primedl offline indicator in the bottom bar.

Building

Requires Bun >= 1.1.

# Install deps (just BiomeJS for linting)
bun install

# Build Firefox extension → dist/
bun run build:firefox

# Build Chrome extension → dist-chrome/
bun run build:chrome

# Build both
bun run build

# Watch mode (Firefox)
bun run dev

# Lint + format
bun run check

Loading in browser

Firefox: about:debugging → This Firefox → Load Temporary Add-on → select dist/manifest.json

Chrome / Brave / Edge: chrome://extensions → Enable Developer mode → Load unpacked → select dist-chrome/

Options

Option	Description
Disable detection	Pause all stream sniffing
Ignore subtitles	Don't capture subtitle URLs
Ignore direct media files	Only capture stream manifests
Auto-download files	Automatically save non-manifest files
Include additional headers	Attach UA, Cookie, Referer to copied commands
primedl relay	Enable/disable sending to the local Rust server
primedl relay port	Port the Rust server listens on (default: 7421)

Architecture

Browser tab
  └── content/keepalive.js        ← keeps Chrome MV3 SW alive
  └── webRequest listeners        ← intercept all network requests
        ↓ stream URL detected
  └── background.js
        ├── cookies.js            ← extract cookies for the tab
        ├── relay.js              ← WebSocket bridge → ws://127.0.0.1:7421
        └── chrome.storage.local  ← persist URL list

popup.html / sidebar.html         ← UI to view/copy/manage detected URLs
options.html                      ← all preferences

WebSocket message format

When a stream is detected, the extension sends:

{
  "type": "stream_detected",
  "version": "1.0",
  "url": "https://example.com/video.m3u8",
  "filename": "video.m3u8",
  "type": "HLS",
  "category": "stream",
  "site": "example.com",
  "tabTitle": "Example Video",
  "tabUrl": "https://example.com/watch",
  "timestamp": 1710000000000,
  "headers": [
    { "name": "user-agent", "value": "Mozilla/5.0 ..." },
    { "name": "referer", "value": "https://example.com/" },
    { "name": "cookie", "value": "session=abc123" }
  ],
  "cookies": "# Netscape HTTP Cookie File\n.example.com\tTRUE\t/\tFALSE\t0\tsession\tabc123",
  "cookieHeader": "session=abc123"
}

The Rust server responds with progress events:

{ "type": "progress", "url": "...", "percent": 45, "speed": "2.3 MB/s" }
{ "type": "download_complete", "url": "...", "path": "/downloads/video.mp4" }
{ "type": "download_error", "url": "...", "error": "Connection refused" }

Locales

Available: English, German, Japanese, Korean, Russian, Slovak.

To add a translation: copy src/_locales/en/messages.json to src/_locales/<lang>/messages.json and translate the message values. Open a pull request.

Credits

Built on top of 54ac/stream-detector (MPL-2.0) with significant modifications for the primedl project.