RealTimePriceTracker

SwiftUI iOS app that simulates real-time stock prices for 25 symbols over a shared WebSocket echo connection.

Screen Recording (Simulator)

Highlights

• Exactly 25 required symbols.
• Single shared WebSocket connection for app lifecycle.
• JSON payload shape:
  • {"symbol":"AAPL","price":226.84,"changePercent":1.23}
• Feed updates every 2 seconds when started.
• Updates apply only from echoed WebSocket messages.
• List sorted by price descending.
• Deep links: stocks://symbol/NVDA.

Architecture (MVVM + Protocol-driven Services)

Models

• Stock (Identifiable)
• StockMessage (Codable)

Protocols

• WebSocketServicing
• PriceFeedGenerating
• TickerServicing

Services

• WebSocketClient (low-level socket)
• WebSocketManager (protocol-conforming service)
• PriceFeedEngine (volatility simulation ±0.2%...±2.5%)
• TimerTickerService (runtime ticker)

DI

• AppDependencies with .live() composition.
• Live dependencies create exactly one websocket service instance used by StocksViewModel.

ViewModel

• StocksViewModel owns stocks, feed state, connection state, sorting, flashing, and message application.
• Depends only on protocols via constructor injection.

Views

• 100% SwiftUI.
• Views consume @EnvironmentObject var viewModel: StocksViewModel.
• Navigation via NavigationStack + .navigationDestination(for: Stock.self).

Deep Link

Configured URL scheme: stocks

Examples:

• stocks://symbol/AAPL
• stocks://symbol/NVDA

Testing

Unit tests use mocks/fakes to avoid network and real timers:

• manual ticker tick injection,
• inbound message injection,
• deterministic sorting/update assertions.

Local Run

1. Open RealTimePriceTracker.xcodeproj in Xcode.
2. Select an iOS simulator (for example iPhone 16).
3. Build and run.
4. Tap Start to begin updates and Stop to pause feed updates.