# iOS samples (Keychain, API key, offline queue)

Use with [docs/ios/README.md](../ios/README.md). These snippets are **reference only** (not a full Xcode project).

## Store API key in Keychain

```swift
import Security

func saveApiKey(_ value: String, service: String = "com.smoa.api") throws {
    let data = Data(value.utf8)
    let query: [String: Any] = [
        kSecClass as String: kSecClassGenericPassword,
        kSecAttrService as String: service,
        kSecAttrAccount as String: "apiKey",
        kSecValueData as String: data
    ]
    SecItemDelete(query as CFDictionary)
    let status = SecItemAdd(query as CFDictionary, nil)
    guard status == errSecSuccess else { throw NSError(domain: NSOSStatusErrorDomain, code: Int(status)) }
}

func loadApiKey(service: String = "com.smoa.api") -> String? {
    let query: [String: Any] = [
        kSecClass as String: kSecClassGenericPassword,
        kSecAttrService as String: service,
        kSecAttrAccount as String: "apiKey",
        kSecReturnData as String: true
    ]
    var out: AnyObject?
    guard SecItemCopyMatching(query as CFDictionary, &out) == errSecSuccess,
          let data = out as? Data else { return nil }
    return String(data: data, encoding: .utf8)
}
```

## Simple offline sync queue (UserDefaults + retry)

Persist operation JSON strings; on `NWPathMonitor` satisfied, POST to `/api/v1/...` with `URLSession` and remove on success.

## Face ID / Touch ID

Wrap Keychain access with `LAContext().evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, …)` before reading sensitive items.

## Certificate pinning

Use `URLSessionDelegate` `urlSession(_:didReceive:completionHandler:)` and compare `SecTrust` server pins to your SPKI hashes.