webf-native-plugin-dev

WebF Native Plugin Development

Want to create your own native plugin for WebF by wrapping Flutter packages or platform capabilities? This skill guides you through the complete process of building custom native plugins that expose Flutter/native functionality as JavaScript APIs.

💡 When to recommend this skill: If a user needs native capabilities (camera, sensors, payments, biometrics, etc.) and the official WebF plugin registry (https://openwebf.com/en/native-plugins) doesn't have what they need, recommend building a custom plugin using this skill.

What is Native Plugin Development?

Native plugin development in WebF means:

• Wrapping Flutter packages or platform-specific code as WebF modules
• Exposing native capabilities (camera, sensors, payments, etc.) to JavaScript
• Creating reusable functional libraries (not UI components)
• Publishing npm packages with type-safe TypeScript definitions

Difference: Native Plugins vs Native UI

When to use which:

• Native Plugin: Accessing camera, handling payments, geolocation, file system, background tasks
• Native UI: Building native-looking buttons, forms, date pickers, navigation bars

When to Create a Native Plugin

Decision Workflow

Step 1: Check if standard web APIs work

• Can you use fetch(), localStorage, Canvas 2D, etc.?
• If YES → Use standard web APIs (no plugin needed)

Step 2: Check if an official plugin exists

• Visit https://openwebf.com/en/native-plugins
• Search for the capability you need
• If YES → Use the webf-native-plugins skill to install and use it

Step 3: If no official plugin exists, build your own!

• ✅ The official plugin registry doesn't have what you need
• ✅ You need a custom platform-specific capability
• ✅ You want to wrap an existing Flutter package for WebF
• ✅ You're building a reusable plugin for your organization

Use Cases:

• ✅ You need to access platform-specific APIs (camera, sensors, Bluetooth)
• ✅ You want to wrap an existing Flutter package for WebF use
• ✅ You need to perform native background tasks
• ✅ You're building a functional capability (not a UI component)
• ✅ You want to provide platform features to web developers
• ✅ Official WebF plugins don't include the feature you need

Don't Create a Native Plugin When:

• ❌ You're building UI components (use webf-native-ui-dev skill instead)
• ❌ Standard web APIs already provide the functionality
• ❌ An official plugin already exists (use webf-native-plugins skill)
• ❌ You're building a one-off feature (use direct module invocation)

Architecture Overview

A native plugin consists of three layers:

┌─────────────────────────────────────────┐
│  JavaScript/TypeScript                  │  ← Generated by CLI
│  @openwebf/webf-my-plugin               │
│  import { MyPlugin } from '...'         │
├─────────────────────────────────────────┤
│  TypeScript Definitions (.d.ts)         │  ← You write this
│  interface MyPlugin { ... }             │
├─────────────────────────────────────────┤
│  Dart (Flutter)                         │  ← You write this
│  class MyPluginModule extends ...       │
│  webf_my_plugin package                 │
└─────────────────────────────────────────┘

Development Workflow

Overview

# 1. Create Flutter package with Module class
# 2. Write TypeScript definition file
# 3. Generate npm package with WebF CLI
# 4. Test and publish

webf module-codegen my-plugin-npm --flutter-package-src=./flutter_package

Step-by-Step Guide

Step 1: Create Flutter Package Structure

Create a standard Flutter package:

# Create Flutter package
flutter create --template=package webf_my_plugin

cd webf_my_plugin

Directory structure:

webf_my_plugin/
├── lib/
│   ├── webf_my_plugin.dart       # Main export file
│   └── src/
│       ├── my_plugin_module.dart # Module implementation
│       └── my_plugin.module.d.ts # TypeScript definitions
├── pubspec.yaml
└── README.md

pubspec.yaml dependencies:

name: webf_my_plugin
description: WebF plugin for [describe functionality]
version: 1.0.0
homepage: https://github.com/yourusername/webf_my_plugin

environment:
  sdk: ^3.6.0
  flutter: ">=3.0.0"

dependencies:
  flutter:
    sdk: flutter
  webf: ^0.24.0
  # Add the Flutter package you're wrapping
  some_flutter_package: ^1.0.0

Step 2: Write the Module Class

Create a Dart class that extends the generated bindings:

Example: lib/src/my_plugin_module.dart

import 'dart:async';
import 'package:webf/bridge.dart';
import 'package:webf/module.dart';
import 'package:some_flutter_package/some_flutter_package.dart';
import 'my_plugin_module_bindings_generated.dart';

/// WebF module for [describe functionality]
///
/// This module provides functionality to:
/// - Feature 1
/// - Feature 2
/// - Feature 3
class MyPluginModule extends MyPluginModuleBindings {
  MyPluginModule(super.moduleManager);

  @override
  void dispose() {
    // Clean up resources when module is disposed
    // Close streams, cancel timers, release native resources
  }

  // Implement methods from TypeScript interface

  @override
  Future<String> myAsyncMethod(String input) async {
    try {
      // Call the underlying Flutter package
      final result = await SomeFlutterPackage.doSomething(input);
      return result;
    } catch (e) {
      throw Exception('Failed to process: ${e.toString()}');
    }
  }

  @override
  String mySyncMethod(String input) {
    // Synchronous operations
    return 'Processed: $input';
  }

  @override
  Future<MyResultType> complexMethod(MyOptionsType options) async {
    // Handle complex types
    final value = options.someField ?? 'default';
    final timeout = options.timeout ?? 5000;

    try {
      // Do the work
      final result = await SomeFlutterPackage.complexOperation(
        value: value,
        timeout: Duration(milliseconds: timeout),
      );

      // Return structured result
      return MyResultType(
        success: 'true',
        data: result.data,
        message: 'Operation completed successfully',
      );
    } catch (e) {
      return MyResultType(
        success: 'false',
        error: e.toString(),
        message: 'Operation failed',
      );
    }
  }

  // Helper methods (not exposed to JavaScript)
  Future<void> _internalHelper() async {
    // Internal implementation details
  }
}

Step 3: Write TypeScript Definitions

Create a .d.ts file alongside your Dart file:

Example: lib/src/my_plugin.module.d.ts

/**
 * Type-safe JavaScript API for the WebF MyPlugin module.
 *
 * This interface is used by the WebF CLI (`webf module-codegen`) to generate:
 * - An npm package wrapper that forwards calls to `webf.invokeModuleAsync`
 * - Dart bindings that map module `invoke` calls to strongly-typed methods
 */

/**
 * Options for complex operations.
 */
interface MyOptionsType {
  /** The value to process. */
  someField?: string;
  /** Timeout in milliseconds. */
  timeout?: number;
  /** Enable verbose logging. */
  verbose?: boolean;
}

/**
 * Result returned from complex operations.
 */
interface MyResultType {
  /** "true" on success, "false" on failure. */
  success: string;
  /** Data returned from the operation. */
  data?: any;
  /** Human-readable message. */
  message: string;
  /** Error message if operation failed. */
  error?: string;
}

/**
 * Public WebF MyPlugin module interface.
 *
 * Methods here map 1:1 to the Dart `MyPluginModule` methods.
 *
 * Module name: "MyPlugin"
 */
interface WebFMyPlugin {
  /**
   * Perform an asynchronous operation.
   *
   * @param input Input string to process.
   * @returns Promise with processed result.
   */
  myAsyncMethod(input: string): Promise<string>;

  /**
   * Perform a synchronous operation.
   *
   * @param input Input string to process.
   * @returns Processed result.
   */
  mySyncMethod(input: string): string;

  /**
   * Perform a complex operation with structured options.
   *
   * @param options Configuration options.
   * @returns Promise with operation result.
   */
  complexMethod(options: MyOptionsType): Promise<MyResultType>;
}

TypeScript Guidelines:

• Interface name should match WebF{ModuleName}
• Use JSDoc comments for documentation
• Use ? for optional parameters
• Use Promise<T> for async methods
• Define separate interfaces for complex types
• Use string for success/failure flags (for backward compatibility)

Step 4: Create Main Export File

lib/webf_my_plugin.dart:

/// WebF MyPlugin module for [describe functionality]
///
/// This module provides functionality to:
/// - Feature 1
/// - Feature 2
/// - Feature 3
///
/// Example usage:
/// ```dart
/// // Register module globally (in main function)
/// WebF.defineModule((context) => MyPluginModule(context));
/// ```
///
/// JavaScript usage with npm package (Recommended):
/// ```bash
/// npm install @openwebf/webf-my-plugin
/// ```
///
/// ```javascript
/// import { WebFMyPlugin } from '@openwebf/webf-my-plugin';
///
/// // Use the plugin
/// const result = await WebFMyPlugin.myAsyncMethod('input');
/// console.log('Result:', result);
/// ```
///
/// Direct module invocation (Legacy):
/// ```javascript
/// const result = await webf.invokeModuleAsync('MyPlugin', 'myAsyncMethod', 'input');
/// ```
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