radar

Finger protocol (RFC 1288) re-imagined for the AT Protocol (atproto) / Bluesky ecosystem

The Finger Connection

In the early days of the internet, the finger command let users scan a remote server to view a person's real-time availability, log-in status, or custom profile snippet (via local .plan files).

As the web centralized, Finger faded away. radar reboots this concept for the modern federated web. Instead of pinging a centralized server, it scans decentralized personal data repositories to pull a user's latest broadcasted status (their most recent post) using public AT Protocol endpoints.

Features

• Zero Dependencies: Simple POSIX shell script using only curl, awk, and sed. Works out of the box on Linux, macOS, and BSD.
• Permissionless: Read-only lookups. No authentication, API keys, or App Passwords required.
• Flexible Formatting: Accepts both modern Bluesky handles (user.bsky.social) and classic finger-style email formats (user@bsky.social).

Installation & Usage

1. Clone or download the script:

   curl -O https://raw.githubusercontent.com/snth/radar/refs/heads/main/radar
   chmod +x radar

2. Scan a user:

   ./radar snth.bsky.social
   # Or using classic finger style:
   ./radar snth@bsky.social

How It Works

1. Normalizes the input handle (converts @ delimiters to .).
2. Resolves the public handle to a Decentralized Identifier (DID) via the AT Protocol Identity endpoints.
3. Fetches the most recent record from the actor's public feed using native string parsing.