3
1

Delete article

Deleted articles cannot be recovered.

Draft of this article would be also deleted.

Are you sure you want to delete this article?

More than 5 years have passed since last update.

DartAdvent Calendar 2016

Day 7

DartでChrome拡張機能でBackgroundとContent Scriptの通信をする

Last updated at Posted at 2016-12-07

背景

DartでChrome拡張機能を作るときにはchromeパッケージを使うと思いますが
sendMessageAPI周りが正しく動かないのであきらめてdart:jsパッケージを使って手動で解決する方法です。

正しく動かないコード

content.dart
main() async {
  var res = await chrome.runtime.sendMessage('soy source');
  print(res);
}
background.dart
main() async* {
  await for (var msgEvent in chrome.runtime.onMessage) {
    print(msgEvent.message);
    msgEvent.sendResponse('hello' + msgEvent.message);
  }
}

Uncaught Error: Could not establish connection. Receiving end does not exist.(...)というエラーが出ます。
error.png

動くコード

context["chrome"]からメッセージング用のAPIを取り出して使います。

Content Script -> Background -> Content Script

content2.dart
void main() {
  context['chrome']['runtime'].callMethod('sendMessage',
      [ "soy source", (result) => print(result)]);//二秒後に "hello tab: xxx name:soy source" と表示されます。
}
background2.dart
void main() {
  var jsObject = context['chrome']['runtime']['onMessage'];
  (jsObject is JsObject ? jsObject : new JsObject.fromBrowserObject(jsObject))
      .callMethod('addListener', [onMessage]);
}

bool onMessage(request, sender,JsFunction response) {
  var tabID = new JsObject.fromBrowserObject(sender)["tab"]["id"];
  new Timer(new Duration(seconds: 2), () {
    response.apply(["hello tab: $tabID name:$request"]);
  });
  return true; //trueにしないと非同期でレスポンスを返せません。
}

Background -> Content Script -> Background

content3.dart
void main(){
  var jsObject = context['chrome']['runtime']['onMessage'];
  (jsObject is JsObject ? jsObject : new JsObject.fromBrowserObject(jsObject))
      .callMethod('addListener', [onMessage]);


}

void onMessage(request, sender,JsFunction sendResponse) {
  print("request $request");
  sendResponse.apply(["hey $request"]);
}
background3.dart
void main() {
  new Timer(new Duration(seconds: 5),(){ //拡張機能をリロードしてから五秒以内にContent Scriptが挿入されているページをリロードしないとうまく動きません。
    context['chrome']['tabs'].callMethod( 
        'sendMessage', [ 376, "マヨネーズ",(result) => print(result)]); //"hey マヨネーズ"と表示されます
  });
}
3
1
0

Register as a new user and use Qiita more conveniently

  1. You get articles that match your needs
  2. You can efficiently read back useful information
  3. You can use dark theme
What you can do with signing up
3
1

Delete article

Deleted articles cannot be recovered.

Draft of this article would be also deleted.

Are you sure you want to delete this article?