DartStream Extension Registration System
Overview
Dartstream is an extensible framework that allows developers to enhance and extend its core functionality through extensions. Extensions are modular components that can add new features, modify existing functionality, or integrate third-party services into Dartstream.
This guide explains how to create, register, and configure extensions in Dartstream, providing step-by-step instructions with practical examples.
Table of Contents
Understanding the Dartstream Extension Registration System
Levels of Extension Registration
Dartstream allows extensions to be registered at three levels, each serving a different purpose:
Core Extensions: These affect Dartstream's core functionality. They can modify or add features to the fundamental components of the framework.
Custom Features: These extend or modify existing core features. They can add specific functionality on top of the core features.
Framework Extensions: These integrate third-party services or tools with Dartstream. They are typically used for connecting external libraries or services like Firebase, AWS, or other frameworks.
Extension Lifecycle
Extensions in Dartstream follow this lifecycle:
Initialization: Set up any dependencies and perform necessary configuration tasks.
Execution: Perform the core functionality of the extension.
Disposal: Clean up resources when the extension is no longer needed.
Each extension follows these phases to ensure it integrates seamlessly into the Dartstream framework.
Creating an Extension Class
Overview
To create a Dartstream extension, you need to implement the DartstreamFeatureExtension interface. This interface defines the essential methods that every extension must implement.
1. Create a New Dartstream Extension Class
To create a new extension, define a class that extends DartstreamFeatureExtension. Here's an example of a simple core extension:
class MyCoreExtension extends DartstreamFeatureExtension {
@override
Future<void> initialize() async {
// Initialization code
print("Initializing MyCoreExtension...");
}
@override
Future<void> execute() async {
// Core functionality code
print("Executing MyCoreExtension functionality...");
}
@override
Future<void> dispose() async {
// Clean-up code
print("Disposing MyCoreExtension...");
}
@override
String get name => 'MyCoreExtension';
@override
String get version => '1.0.0';
@override
String get compatibleVersion => '>=2.0.0';
@override
List<String> get requiredExtensions => [];
@override
String get description => 'A sample core extension for Dartstream';
@override
String get documentationUrl => 'http://docs.mycoreextension.com';
}2.1 Explanation of Interface Methods
The DartstreamFeatureExtension interface provides several key methods and properties that your extension must implement:
initialize(): This method is called when the extension is initialized. It's used to set up any services, dependencies, or configurations needed for the extension to work.execute(): This method defines the core functionality of the extension. This is where your extension performs its main tasks, such as modifying data, interacting with other services, or providing new features.dispose(): This method is called when the extension is no longer needed. It allows you to clean up resources, close connections, or perform any necessary shutdown tasks.name: The name of the extension. It should be unique to avoid conflicts with other extensions.version: The version of your extension. This helps track changes and ensure compatibility with different versions of Dartstream.compatibleVersion: Specifies the minimum version of Dartstream that is compatible with your extension.requiredExtensions: This property lists other extensions that your extension depends on. Dartstream will ensure that these extensions are initialized before your extension.description: A brief description of what your extension does. This is useful for documentation purposes.documentationUrl: A URL where users can find more information about the extension.
Registering Extensions
Overview
Once you've created your extension class, the next step is to register it with the Dartstream framework. Dartstream provides an extension system that allows you to register your extensions at different levels (core, custom, or framework).
3.1 Registering Core Extensions
Core extensions are foundational extensions that modify or enhance Dartstream's core features. Here's how you can register a core extension:
Example:
DartstreamExtensionSystem extensionSystem = DartstreamExtensionSystem(
container: diContainer,
services: services,
logger: logger,
);
await extensionSystem.registerCoreExtension(MyCoreExtension());In this example, DartstreamExtensionSystem is used to register the MyCoreExtension class. Once registered, Dartstream will initialize the core extension and its associated services.
3.2 Registering Custom Features
Custom features extend the functionality of core extensions. Here's how to register a custom feature that builds on top of a core extension:
Example:
await extensionSystem.registerCustomFeature(MyCustomFeature(), 'MyCoreExtension');In this example, MyCustomFeature extends MyCoreExtension, and the registration ensures that the core extension is initialized before the custom feature.
3.3 Registering Framework Extensions
Framework extensions are used to integrate third-party services or tools into Dartstream. For example, you might register an extension that connects Dartstream to Firebase or AWS.
Example:
await extensionSystem.registerFrameworkExtension(
MyFrameworkExtension(),
'Firebase',
'MyCoreExtension',
);Here, MyFrameworkExtension integrates with Firebase, and the registration links it to the core extension (MyCoreExtension) that it depends on.
Testing and Debugging Extensions
Debugging Extensions
When developing extensions, use the DartstreamLogger to track the execution of your extensions and troubleshoot any issues. Here's an example of how you can log messages within your extension:
_logger.log('MyCoreExtension initialized');Unit Testing Extensions
To unit test your extensions, you can mock the services and dependencies using packages like mockito or mocktail. This allows you to test the extension's behavior in isolation.
Example:
final mockService = MockService();
final extension = MyCoreExtension(service: mockService);
test('Test MyCoreExtension initialization', () {
extension.initialize();
expect(mockService.called, true);
});Advanced Features
Lazy Loading Extensions
Extensions can be loaded lazily to improve startup performance. This means extensions are only loaded when they're needed, rather than at application startup.
Dependency Management
Dartstream ensures that extensions are loaded in the correct order, based on their dependencies. Use the requiredExtensions property to specify which extensions your feature depends on.
Common Pitfalls and Troubleshooting
Missing Dependencies
If you encounter errors about missing dependencies, check that the required extensions are registered correctly. Ensure that the extension names in the requiredExtensions list are accurate.
Version Compatibility Issues
Ensure the version numbers for your extensions are compatible with your Dartstream version. Use the compatibleVersion property to specify version compatibility.
Conclusion
Summary
This guide covered the entire process of registering core, custom, and framework extensions in Dartstream. You learned how to create your own extensions, integrate third-party services, and extend Dartstream's core functionality.
Next Steps
Now that you understand the registration process, try creating your own extensions. Use the provided examples as a starting point and adjust them based on your project's needs.
This documentation structure is comprehensive and organized, ensuring that users can easily follow along from creating their first extension to integrating complex third-party services. It includes all relevant code samples, explanations of interface methods, troubleshooting tips, and advanced features to give users a well-rounded understanding of how to extend Dartstream.
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