Handler for POST /sip/transfer endpoint

Initiates a SIP REFER transfer for a participant in a LiveKit room. The transfer moves an ongoing SIP call to a different phone number.

Arguments

• state - Shared application state containing LiveKit handlers
• auth - Authentication context for room metadata authorization
• request - Transfer request with room name, participant identity, and destination

Returns

• Response - JSON response with transfer status or error

Errors

• 400 Bad Request - Invalid phone number format or empty fields
• 404 Not Found - Room not found, not accessible, or participant not found
• 500 Internal Server Error - LiveKit not configured or transfer operation failed

Flow

1. Validate the phone number format
2. Check LiveKit handlers are configured
3. Check room access via metadata auth_id
4. Verify the participant exists and is a SIP participant
5. Execute the SIP transfer
6. Return success or appropriate error

{
  "room_name": "call-room-123",
  "participant_identity": "sip_participant_456",
  "transfer_to": "+15551234567"
}

{
  "participant_identity": "sip_participant_456",
  "room_name": "call-room-123",
  "transfer_to": "+15551234567"
}

{
  "status": "initiated",
  "room_name": "call-room-123",
  "participant_identity": "sip_participant_456",
  "transfer_to": "tel:+15551234567"
}

{
  "participant_identity": "sip_participant_456",
  "room_name": "call-room-123",
  "status": "initiated",
  "transfer_to": "tel:+15551234567"
}