feat: Add WebSocket-based log broadcast support for Android and iOS

[Copilot]

List of changes

Implements WebSocket-based real-time log streaming for Android (logcat) and iOS (syslog) via Appium server endpoints, matching the Java client API surface from PR#858 and PR#871.

Core Infrastructure:

• StringWebSocketClient using System.Net.WebSockets.ClientWebSocket for async message handling
• Handler interfaces: ICanHandleMessages<T>, ICanHandleErrors, ICanHandleConnects, ICanHandleDisconnects

Android Support:

• IListensToLogcatMessages interface and AndroidDriver implementation
• Methods: StartLogcatBroadcast(), AddLogcatMessagesListener(), StopLogcatBroadcast(), etc.
• Integration tests: LogcatBroadcastTests.cs with 5 comprehensive test cases

iOS Support:

• IListensToSyslogMessages interface and IOSDriver implementation
• Methods: StartSyslogBroadcast(), AddSyslogMessagesListener(), StopSyslogBroadcast(), etc.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change that adds functionality or value)
• Breaking change (fix or feature that would cause existing functionality not to work as expected)
• Test fix (non-breaking change that improves test stability or correctness)

Documentation

• Have you proposed a file change/ PR with Appium to update documentation?

This can be done by navigating to the documentation section on http://appium.io selecting the appropriate command/endpoint and clicking the 'Edit this doc' link to update the C# example

Integration tests

• Have you provided integration tests for your changes? (required for Bugfix, New feature, or Test fix)

Details

Android logcat streaming:

var driver = new AndroidDriver(options);

driver.AddLogcatMessagesListener(msg => Console.WriteLine($"[LOGCAT] {msg}"));
driver.AddLogcatErrorsListener(ex => Console.WriteLine($"Error: {ex.Message}"));

driver.StartLogcatBroadcast(); // localhost:4723 default
// or: driver.StartLogcatBroadcast("192.168.1.100", 4723);

driver.StopLogcatBroadcast();
driver.RemoveAllLogcatListeners();

iOS syslog streaming:

var driver = new IOSDriver(options);

driver.AddSyslogMessagesListener(msg => Console.WriteLine($"[SYSLOG] {msg}"));
driver.AddSyslogConnectionListener(() => Console.WriteLine("Connected"));

driver.StartSyslogBroadcast();
driver.StopSyslogBroadcast();
driver.RemoveAllSyslogListeners();

Integration Tests for Android:

Added comprehensive test suite in test/integration/Android/Session/LogcatBroadcastTests.cs:

• VerifyLogcatListenerCanBeAssigned - Validates listeners receive messages and connections work
• CanStartAndStopLogcatBroadcast - Tests basic start/stop operations
• CanStartLogcatBroadcastWithCustomHost - Tests custom host/port configuration
• CanAddAndRemoveMultipleListeners - Validates multiple listeners and removal functionality
• CanHandleErrorsGracefully - Tests error handling behavior

Tests follow the pattern from Java client (PR appium#858) and use SemaphoreSlim for async coordination.

Requirements:

• Appium server with log broadcast endpoint support
• appium-uiautomator2-driver (Android) or appium-xcuitest-driver (iOS)

Technical notes:

• Uses mobile: startLogsBroadcast and mobile: stopLogsBroadcast extension commands
• WebSocket endpoint: ws://{host}:{port}/ws/session/{sessionId}/appium/device/{logcat|syslog}
• Thread-safe handler collections
• Zero external dependencies (built-in .NET WebSockets)
• .NET Standard 2.0 compatible

Original prompt

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This section details on the original issue you should resolve

<issue_title>feat: Add support for log broadcast endpoints appium#255</issue_title>
<issue_description>appium/java-client#871 - iOS
appium/java-client#858 - Android</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes feat: Add support for log broadcast endpoints #169

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[Dor-bl]

@copilot please add related tests to the android logcat feature.

[Copilot]

@copilot please add related tests to the android logcat feature.

Added comprehensive integration tests for Android logcat broadcast feature in commit 871a4db.

The test suite includes:

• VerifyLogcatListenerCanBeAssigned - Validates listeners receive messages and connections work
• CanStartAndStopLogcatBroadcast - Tests basic start/stop operations
• CanStartLogcatBroadcastWithCustomHost - Tests custom host/port configuration
• CanAddAndRemoveMultipleListeners - Validates multiple listeners and removal functionality
• CanHandleErrorsGracefully - Tests error handling behavior

Tests follow the pattern from Java client (PR appium#858) and existing .NET integration tests, using SemaphoreSlim for async coordination and proper setup/teardown.