Is iOS webrtc communication based on webview stable when app is background

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Summary

The stability of iOS WebRTC communication via WebView when an app is in the background is a significant concern for developers implementing SIP communication using JsSIP within a WebView. Key considerations include resource limitations and background mode declarations.

Root Cause

The root cause of potential instability in iOS WebRTC communication via WebView when the app is backgrounded includes:

  • System resource limitations: The system may limit resources allocated to backgrounded apps.
  • Background mode permissions: Even with VoIP background mode declared in the Info.plist file, the system may not preserve sufficient resources for SIP communication.

Why This Happens in Real Systems

This issue occurs in real systems due to:

  • iOS power management: iOS is designed to manage power efficiently, which can lead to resource constraints for backgrounded apps.
  • Multi-tasking limitations: While iOS supports multi-tasking, backgrounded apps may face limitations in terms of CPU and memory usage.

Real-World Impact

The real-world impact of unstable iOS WebRTC communication via WebView when the app is backgrounded includes:

  • Dropped calls: SIP communication may be interrupted or terminated when the app is backgrounded.
  • Poor user experience: Users may experience connectivity issues or call drops, leading to a poor user experience.

Example or Code

// JsSIP example
var socket = new JsSIP.WebSocketInterface('ws://sip-ws.example.com');
var ua = new JsSIP.UA({
  uri: 'sip:alice@example.com',
  sockets: [socket]
});

How Senior Engineers Fix It

Senior engineers fix this issue by:

  • Optimizing resource usage: Ensuring that the app uses resources efficiently to minimize the impact of system limitations.
  • Implementing background mode handling: Properly handling background mode to maintain SIP communication when the app is backgrounded.

Why Juniors Miss It

Junior engineers may miss this issue due to:

  • Lack of experience: Inexperienced engineers may not be aware of the resource limitations and background mode considerations in iOS.
  • Insufficient testing: Juniors may not thoroughly test their app in background mode, leading to connectivity issues and call drops.