mirror of
https://github.com/wgh136/flutter_qjs.git
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96 lines
2.7 KiB
Markdown
96 lines
2.7 KiB
Markdown
<!--
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* @Description:
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* @Author: ekibun
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* @Date: 2020-08-08 08:16:50
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* @LastEditors: ekibun
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* @LastEditTime: 2020-08-27 21:11:55
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-->
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# flutter_qjs
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A quickjs engine for flutter.
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## Feature
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This plugin is a simple js engine for flutter using the `quickjs` project. Plugin currently supports Windows, Linux, and Android.
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Each `FlutterJs` object creates a new thread that runs a simple js loop.
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ES6 module with `import` function is supported and can manage in dart with `setModuleHandler`.
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A global async function `dart` is presented to invoke dart function, and `Promise` is supported so that you can use `await` or `then` to get external result from `dart`. Data convertion between dart and js are implemented as follow:
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| dart | js |
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| --- | --- |
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| Bool | boolean |
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| Int | number |
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| Double | number |
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| String | string |
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| Uint8List/Int32List/Int64List | ArrayBuffer |
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| Float64List | number[] |
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| List | Array |
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| Map | Object |
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| Closure(List) => Future | function(....args) |
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**notice:**
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1. All the `Uint8List/Int32List/Int64List` sent from dart will be converted to `ArrayBuffer` without marked the size of elements, and the `ArrayBuffer` will be converted to `Uint8List`.
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2. `function` can only sent from js to dart and all the arguments will be packed in a dart `List` object.
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## Getting Started
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1. Create a `FlutterJs` object. Make sure call `destroy` to terminate thread and release memory when you don't need it.
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```dart
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FlutterJs engine = FlutterJs();
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// do something ...
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await engine.destroy();
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engine = null;
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```
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2. Call `setMethodHandler` to implements `dart` interaction. For example, you can use `Dio` to implements http in js:
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```dart
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await engine.setMethodHandler((String method, List arg) async {
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switch (method) {
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case "http":
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Response response = await Dio().get(arg[0]);
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return response.data;
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default:
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return JsMethodHandlerNotImplement();
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}
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});
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```
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and in javascript, call `dart` function to get data:
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```javascript
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dart("http", "http://example.com/");
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```
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3. Call `setModuleHandler` to resolve js module. For example, you can use assets files as module:
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```dart
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await engine.setModuleHandler((String module) async {
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return await rootBundle.loadString(
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"js/" + module.replaceFirst(new RegExp(r".js$"), "") + ".js");
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});
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```
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and in javascript, call `import` function to get module:
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```javascript
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import("hello").then(({default: greet}) => greet("world"));
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```
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4. Use `evaluate` to run js script, and try-catch is needed to capture js exception.
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```dart
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try {
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print(await engine.evaluate(code ?? '', "<eval>"));
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} catch (e) {
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print(e.toString());
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}
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```
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[This example](example/lib/main.dart) contains a complete demonstration on how to use this plugin.
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