Omiai

Omiai is the Phoenix signaling relay used by XiaDianxin/Sankaku peers.

Key Capabilities

• Authenticated websocket signaling socket at /ws/sankaku (OmiaiWeb.SankakuSocket)
• Peer channel topics: peer:<public_key> (OmiaiWeb.SignalingChannel)
• Dual event contract routing (canonical SDP events + legacy aliases)
• Presence tracking for online peer fast-fail behavior
• Quicdial runtime registry: public_key => peer_ip while peer is connected
• resolve_quicdial channel event for resolving a target Quicdial code to current IP
• mDNS advertisement for zero-config LAN discovery (_omiai._tcp)

Quicdial Resolution Flow

1. Peer connects websocket with public_key.
2. Socket extracts peer_data IP from endpoint connect_info.
3. OmiaiWeb.QuicdialRegistry stores %{public_key => ip} for that socket process.
4. Caller pushes:

{
  "event": "resolve_quicdial",
  "payload": { "code": "target_public_key" }
}

5. Channel replies:
   • Success: %{ip: "203.0.113.10"}
   • Failure: %{"reason" => "offline"}

IPv4 and IPv6 peer tuples are both supported when extracting peer_data.address.

Startup Registration Handshake

After websocket upgrade, clients should push this payload to register_startup:

{
  "public_key": "alice_public_key",
  "session_token": "session-token",
  "sig_ts": "1741205660123",
  "sig_nonce": "f1ec6d6a-18c7-43d4-b5b4-c73c97f4a70e"
}

Omiai refreshes Presence metadata and Quicdial IP mapping on that call.

mDNS Broadcast

Omiai advertises itself on LAN as:

• Service type: _omiai._tcp
• Instance: Omiai_Local_Node
• Port: endpoint HTTP port (default 4000)
• TXT payload includes websocket path: /ws/sankaku/websocket

Local Development

mix setup
mix phx.server

Dev endpoint binds on 0.0.0.0:4000 for LAN/iOS device testing. Websocket endpoint is ws://<LAN-IP>:4000/ws/sankaku/websocket.

Testing

mix test

Channel tests cover:

• Canonical/legacy event routing
• Presence lifecycle
• Quicdial resolve success/offline behavior