Join & Rejoin¶

What this covers¶

• Joining an active call (initial join)
• Rejoin flow (reconnect after app restart / disconnect)

API Endpoints (code-aligned)¶

• Join: POST /app/api/call/{id}/join
• Request rejoin: POST /app/api/call/{id}/request-rejoin
• Rejoin: POST /app/api/call/{id}/rejoin
• Participants: GET /app/api/call/{id}/participants

Canonical Code¶

• Session manager: ecall/Modules/Call/Managers/GroupCallSessionManager.swift
• Signaling handler: ecall/Modules/Call/Managers/CallSignalingHandler.swift
• handleParticipantRequestRejoin(_:)
• handleParticipantAcceptRejoin(_:)
• Encryption: ecall/Modules/Call/Managers/CallEncryptionManager.swift

Rejoin Flow (high-level)¶

1. User taps Rejoin.
2. Client sends POST /app/api/call/{callId}/request-rejoin.
3. Backend broadcasts participant_request_rejoin to active participants via STOMP.
4. An active participant:
5. fetches requester's public key
6. encrypts the current AES key for the requester
7. sends participant_accept_rejoin with encryptedAESKey
8. Rejoining device:
9. receives participant_accept_rejoin
10. decrypts AES key
11. calls POST /app/api/call/{callId}/rejoin

Security notes¶

• AES key is encrypted using the requester's public key (P-256 preferred#59; RSA fallback).
• Private keys never leave the device.

Diagram¶

• ./diagrams/join-rejoin-flow.md