SharpHook 8.0.0

SharpHook

SharpHook provides a cross-platform global keyboard and mouse hook, event simulation, and text entry simulation for .NET. It is a wrapper of libuiohook and provides direct access to its features as well as higher-level types to work with it.

Usage

Global Hooks

SharpHook provides the IGlobalHook interface along with three default implementations which you can use to control the hook and subscribe to its events. Here's a basic usage example:

using SharpHook;

var hook = new EventLoopGlobalHook();

// Events of type EventHandler<HookEventArgs>:
hook.HookEnabled += OnHookEnabled;
hook.HookDisabled += OnHookDisabled;

// Events of type EventHandler<KeyboardHookEventArgs>:
hook.KeyTyped += OnKeyTyped; // Disabled by default
hook.KeyPressed += OnKeyPressed;
hook.KeyReleased += OnKeyReleased;

// Events of type EventHandler<MouseHookEventArgs>:
hook.MouseClicked += OnMouseClicked;
hook.MousePressed += OnMousePressed;
hook.MouseReleased += OnMouseReleased;
hook.MouseMoved += OnMouseMoved;
hook.MouseMovedRelative += OnMouseMovedRelative;
hook.MouseDragged += OnMouseDragged;
hook.MouseDraggedRelative += OnMouseDraggedRelative;

// Events of type EventHandler<MouseWheelHookEventArgs>:
hook.MouseWheel += OnMouseWheel;

hook.Run();
// or
await hook.RunAsync();

First, you create the hook, then subscribe to its events, and then run it. The Run method runs the hook on the current thread, blocking it. The RunAsync() method runs the hook on a separate thread and returns a Task which is finished when the hook is stopped. You can subscribe to events after the hook is started.

IGlobalHook contains the Stop method to stop the global hook. After stopping, the global hook can be started again by calling the Run or RunAsync method. Calling Stop when the hook is not running won't do anything.

IGlobalHook extends IDisposable. When you call the Dispose method on a hook, it's disposed and stopped if it was running. Once a hook has been disposed, it cannot be started again – you'll have to create a new instance. Calling Dispose when the hook is not running won't do anything other than marking the instance as disposed.

Hook events are of type HookEventArgs or a derived type which contains more info. It's possible to suppress event propagation by setting the SuppressEvent property to true inside the event handler. This must be done synchronously and is only supported on Windows and macOS. You can check the event time and whether the event is real or simulated with the EventTime and IsEventSimulated properties respectively.

Important: Always use one instance of IGlobalHook at a time in the entire application since they all must use the same static method to set the hook callback for libuiohook, so there may only be one callback at a time. Running a global hook when another global hook is already running will corrupt the internal global state of libuiohook.

You can create a keyboard-only or a mouse-only hook by passing a GlobalHookType to Run or RunAsync. On Windows, there are two different global hooks – a keyboard hook and a mouse hook. On macOS and Linux, there is one hook for all events, and this enables filtering keyboard or mouse events out on these OSes, though on Wayland, the connection to the compositor will be established only if mouse events are enabled since they need to know the screen size and bounds.

On Wayland, absolute mouse position is usually not available, so you should subscribe to the MouseMovedRelative and MouseDraggedRelative in addition to MouseMoved and MouseDragged if you want to listen to mouse movement. On other platforms, relative motion events are never raised.

SharpHook provides three implementations of IGlobalHook:

• SharpHook.SimpleGlobalHook runs all of its event handlers on the same thread on which the hook itself runs. This means that the handlers should generally be fast since they will block the hook from handling the events that follow if they run for too long.

• SharpHook.EventLoopGlobalHook runs all of its event handlers on a separate dedicated thread. On backpressure it will queue the remaining events which means that the hook will be able to process all events. This implementation should be preferred to SimpleGlobalHook except for very simple use-cases. But it has a downside – suppressing event propagation will be ignored since event handlers are executed on another thread.

• SharpHook.TaskPoolGlobalHook runs all of its event handlers on other threads inside the default thread pool for tasks. The parallelism level of the handlers can be configured. On backpressure it will queue the remaining events which means that the hook will be able to process all events. Like with EventLoopGlobalHook, suppressing event propagation will be ignored since event handlers are executed on other threads. In general, EventLoopGlobalHook should be preferred instead, as this class provides benefits only if events should be processed in parallel, which is rarely the case.

The library also provides the SharpHook.GlobalHookBase class which you can extend to create your own implementation of the global hook. It calls the appropriate event handlers, and you only need to implement a strategy for dispatching the events. It also keeps a reference to a running global hook so that it's not garbage-collected.

The library also provides the IBasicGlobalHook interface and the BasicGlobalHookBase class. This class can be extended to create a custom global hook which has a different form of events from that in IGlobalHook.

Reactive Global Hooks

Use the SharpHook.Reactive package for reactive global hooks with the Rx.NET integration.

Use the SharpHook.ReactiveUI package for reactive global hooks with the ReactiveUI.Primitives integration.

Use the SharpHook.R3 package for reactive global hooks with the R3 integration.

Event Simulation

SharpHook provides the ability to simulate keyboard and mouse events in a cross-platform way as well. Here's a quick example:

using SharpHook;
using SharpHook.Data;

using var simulator = EventSimulator.Create("Your application name");

// Press Ctrl+C
simulator.SimulateKeyPress(KeyCode.VcLeftControl);
simulator.SimulateKeyPress(KeyCode.VcC);

// Release Ctrl+C
simulator.SimulateKeyRelease(KeyCode.VcC);
simulator.SimulateKeyRelease(KeyCode.VcLeftControl);

// Simulate pressing Ctrl, then pressing C, then releasing C, then releasing Ctrl
simulator.SimulateKeyStroke(KeyCode.VcLeftControl, KeyCode.VcC);

// Press the left mouse button
simulator.SimulateMousePress(MouseButton.Button1);

// Release the left mouse button
simulator.SimulateMouseRelease(MouseButton.Button1);

// Press the left mouse button at (0, 0)
simulator.SimulateMousePress(0, 0, MouseButton.Button1);

// Release the left mouse button at (0, 0)
simulator.SimulateMouseRelease(0, 0, MouseButton.Button1);

// Move the mouse pointer to (0, 0)
simulator.SimulateMouseMovement(0, 0);

// Move the mouse pointer 50 pixels to the right and 100 pixels down
simulator.SimulateMouseMovementRelative(50, 100);

// Scroll the mouse wheel
simulator.SimulateMouseWheel(
    rotation: -120,
    direction: MouseWheelScrollDirection.Vertical, // Vertical by default
    type: MouseWheelScrollType.UnitScroll); // UnitScroll by default

SharpHook provides the IEventSimulator interface, and the default implementation, EventSimulator.

Text Entry Simulation

SharpHook also provides text entry simulation. IEventSimulator contains the SimulateTextEntry method which accepts a string. The text to simulate doesn't depend on the current keyboard layout. The full range of UTF-16 (including surrogate pairs, e.g., emojis) is supported.

Note that on Wayland, text entry simulation is not supported.

Low-Level Functionality

SharpHook exposes the functionality of libuiohook through low-level providers in the SharpHook.Providers namespace. The SharpHook.Data namespace contains types which represent the data used by libuiohook.

In general, you don't need to use the low-level types directly. Instead, use the higher-level interfaces and classes provided by SharpHook. However, you should still read this section to know how the high-level features work under the hood.

There are multiple interfaces in SharpHook.Providers, each of which represents a part of libuiohook's functionality. SharpHook.Providers.UioHookProvider implements all of these interfaces and simply calls the corresponding functions in libuiohook. In order to use this class, use UioHookProvider.Instance – its single instance.

IGlobalHookProvider contains the following members for working with the global hook:

• SetDispatchProc – sets the function which will be called when an event is raised by libuiohook.
• Run – creates a keyboard and mouse global hook and runs it on the current thread, blocking it until Stop is called.
• RunKeyboard – creates a keyboard-only global hook and runs it on the current thread, blocking it until Stop is called.
• RunMouse – creates a mouse-only global hook and runs it on the current thread, blocking it until Stop is called.
• Stop – stops the global hook.
• KeyTypedEnabled - gets or sets the value which specifies whether events of type KeyTyped are enabled.

IEventSimulationProvider contains the PostEvent method for simulating input events. It also contains the PostText method which simulates text entry. On Linux, it's required to create virtual input devices before simulating input events. IEventSimulationProvider contains the InitializeVirtualDevices and DestroyVirtualDevices methods for that.

All higher-level classes accept low-level providers in their constructors. By default, they use UioHookProvider, but it can be swapped for a fake provider in testing, for example.

Here's the list of all interfaces in SharpHook.Providers:

• IAccessibilityProvider – provides configuration for the macOS Accessibility API.
• IDeviceProcsProvider – provides a way to override privileged device opening/closing functions on Linux.
• IEventSimulationProvider – provides the event simulation functionality.
• IFeatureProvider – provides information on optional features supported by the current platform.
• IGlobalHookProvider – provides the global hook functionality.
• IKeyboardInfoProvider – provides low-level information about the keyboard.
• ILinuxBackendProvider – provides the Linux backend configuration.
• ILoggingProvider – provides the libuiohook logging functionality.
• IMouseInfoProvider – provides low-level information about the mouse.
• IScreenInfoProvider – provides low-level information about screens.

Querying Optional Feature Support

Some libuiohook features are considered 'optional' and are not supported on all platforms. The IFeatureProvider interface has the GetOptionalFeatureSupport method which returns UioHookFeature – a flag enum which represents the optional features and has the following values:

• EventSuppression – if this feature is supported, then event suppression works.
• KeyTypedEvents – if this feature is supported, then events of type KeyTyped work. If not, then calling UioHookProvider.Instance.KeyTypedEnabled = true does nothing.
• PostText – if this feature is supported, then simulating text entry works.
• KeyAutoRepeat – if this feature is supported, then keeping a key pressed will raise repeated KeyPressed events. If not, the only one KeyPressed event will be raised.
• AbsoluteMouseMovement – if this feature is supported, then mouse motion events will always include absolute mouse coordinates, so MouseMoved or MouseDragged will always be raised. If not, then MouseMovedRelative or MouseDraggedRelative may be raised instead.
• AbsoluteMouseButtonCoordinates – if this feature is supported, then mouse coordinates will be present in MousePressed, MouseReleased, MouseClicked, and MouseWheel events. If not, then the coordinates will always be (0, 0).
• PointerProperties – if this feature is supported, then the GetPointerAccelerationMultiplier, GetPointerAccelerationThreshold, and GetPointerSensitivity methods in IMouseInfoProvider work. If not, then they always return -1.

Windows and macOS support all of these features. X11 supports all of them, except EventSuppression. Wayland supports none of these features.

Logging

libuiohook can log messages throughout its execution. By default the messages are not logged anywhere, but you can get these logs by using the ILogSource interface and its default implementation, LogSource:

using SharpHook.Logging;

var logSource = LogSource.RegisterOrGet(minLevel: LogLevel.Info);
logSource.MessageLogged += this.OnMessageLogged;

private void OnMessageLogged(object? sender, LogEventArgs e) =>
    this.logger.Log(this.AdaptLogLevel(e.LogEntry.Level), e.LogEntry.FullText);

ILogSource extends IDisposable – you can dispose of a log source to stop receiving libuiohook messages.

An EmptyLogSource class is also available – this class doesn't listen to the libuiohook logs and can be used instead of LogSource in release builds.

Testing

You can use the SharpHook.Testing package to simplify testing as it provides test utility classes.

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