PluginTask

🧩 A Task that supports plugins

PluginTask is a custom Task that allows users to add plugins to modify its behavior. Plugins can be added to the PluginTask instance to perform additional functionality before or after the task's main operation. This makes it easy to modify the task's behavior without modifying its original implementation.

Usage

Creating a TaskPluginManager

The TaskPluginManager is responsible for managing the plugins that are registered with it. You can create a new TaskPluginManager instance by initializing it with an array of Plugin instances.

class ImageTaskPluginManager: TaskPluginManager<Void> {
    var image: Image?
}

Creating a TaskPlugin

Before creating a PluginTask, you need to create a TaskPlugin to implement the additional functionality that you want to add. A TaskPlugin is a Swift struct or class that conforms to the Plugin protocol and implements the required handle method.

struct ImageDownloadingPlugin: TaskPlugin {
    var keyPath: WritableKeyPath<ImageTaskPluginManager, Image?> = \.image

    func handle(value: URL, output: inout Image?) async throws {
        let data: Data = try await fetchImage(url: value)
        let image: UIImage = UIImage(data: data)!
        output = Image(uiImage: image)
    }
}

In this example, we define a custom TaskPluginManager that includes a property to hold the downloaded image. We then define a TaskPlugin that downloads an image from a given URL and stores it in the TaskPluginManager.

Creating a PluginTask

To create a PluginTask, you need to initialize it with a TaskPluginManager. The TaskPluginManager is responsible for managing the plugins and invoking them at the appropriate times during the task's execution.

let taskPluginManager = ImageTaskPluginManager()
let pluginTask: Task<Void, Error> = PluginTask(manager: taskPluginManager) { manager in
    let url = URL(string: "https://example.com/image.jpg")!
    try await manager.handle(value: url)
}

In this example, we create a new ImageTaskPluginManager instance and use it to initialize a new PluginTask. We then define the main operation of the task, which downloads an image from a URL and stores it in the TaskPluginManager using the handle method.