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james 3e3aba4157 Add Reddit video support

Reddit links now download and post like the other platforms.

Two changes were needed, not just the URL pattern:

- Regex: yt-dlp's Reddit extractor only matches /comments/ permalinks, so
  the app's /r/<sub>/s/<code> share links and redd.it / v.redd.it
  shortlinks are listed explicitly — they redirect to the canonical URL,
  which yt-dlp follows. Without them the link is silently dropped.

- Format selector: Reddit publishes video and audio as separate DASH/HLS
  streams with no muxed rendition, so every `best...` term failed and
  yt-dlp aborted with "Requested format is not available". Added a
  bv*+ba merge tail (and a bare bv* for silent videos) to the normal and
  /force selectors. Muxed hosts still resolve at the earlier terms, so
  YouTube/IG/TikTok/X selection is unchanged.

Posts with no video report "No media found", already in the silent list,
so ordinary Reddit links shared in chat draw no reply.

2026-08-14 05:00:16 -04:00

3.4 KiB

Raw Blame History

signal-bot

A Signal group-chat bot that grabs videos from links people post (X/Twitter, Instagram, YouTube, TikTok, Reddit) and posts them back into the chat, plus a couple of toys for messing with the last video.

What it does

Auto-download — watches every group message for a supported link and replies with the video. Powered by yt-dlp. Videos over 100 MB are auto re-encoded with ffmpeg to fit.
/speed [n] — re-posts the last video sped up n× (default 2×), pitch-shifted like tape. e.g. /speed 4, /speed 0.5.
/rev — re-posts the last video reversed (audio too).
/cookies (DM, admins only) — paste exported .instagram.com cookie lines to refresh Instagram auth without touching the server.

Supported links: x.com / twitter.com (and fxtwitter/vxtwitter/fixupx wrappers), instagram.com/reel|p, youtube.com / youtu.be / Shorts, TikTok, and Reddit (/comments/ permalinks, /s/ app share links, redd.it and v.redd.it shortlinks). Reddit posts with no video stay silent.

How it's wired

Signal  ──►  signal-cli-rest-api (json-rpc, :8080)  ──►  bot.py (signalbot lib)
                  [docker-compose.yml]                      [systemd service]
                                                                  │
                                                       yt-dlp + ffmpeg + cookies.txt

bot.py connects to a signal-cli-rest-api daemon over a websocket in json-rpc mode.
docker-compose.yml runs that daemon; the linked-account data lives in a ./signal-cli-data volume (gitignored — it holds private keys).
signal-bot.service.example is the systemd unit that runs bot.py.

Setup

Run signal-cli-rest-api and link it as a device to your Signal account:
```
docker compose up -d
```
Then link via the QR at http://127.0.0.1:8080/v1/qrcodelink?device_name=bot (scan from Signal → Settings → Linked devices). Keep signal-cli up to date — an out-of-date signal-cli silently stops receiving messages when Signal changes its server protocol (getServerGuid must not be null in the logs); docker compose pull && docker compose up -d fixes it.
Python env:
```
python3 -m venv venv
venv/bin/pip install -r requirements.txt
```
YouTube also needs Node >= 22 on PATH (for yt-dlp-ejs's challenge solver). If your distro only ships an older Node, install a standalone Node 22+ and point bot.py's _NODE22 at it. Note: YouTube cookies are deliberately withheld (_cookie_args) — sending account cookies forces yt-dlp onto a player client whose media URLs 403; cookieless YouTube requests work.
Cookies: copy cookies.txt.example to cookies.txt and fill in real exported cookies for the sites you want auth'd. (gitignored)
Service: copy signal-bot.service.example to signal-bot.service, set your user / phone number / paths, install it:
```
sudo cp signal-bot.service /etc/systemd/system/
sudo systemctl enable --now signal-bot
```

Notes

The bot only acts in group chats (except /cookies, which is DM-only).
Reply-targeting (e.g. "speed up this video") was intentionally dropped: Signal Desktop strips quote metadata from synced transcripts, so /speed and /rev always act on the last video seen in the group.