Dart: PointyCastle计算异步

Question

目前，我正试图将凭据数据发送到后端，因此，为了安全起见，我希望散列密码。

但是当我使用PassCrypt().hashPass("", passwd, 48)方法时，整个应用程序会冻结近1-2秒。有没有一种异步等待输入的方法？

谢谢:)

Answer 1

您可以复制粘贴，运行下面的完整代码

您可以使用compute并通过then获得结果。

在演示中，您可以看到浮动操作按钮没有被阻塞。

代码段

Future<String> hashJob(String password) async {
      return compute(hashPassword, password);
    }

String hashPassword(String password) {
      return PassCrypt().hashPass("", password, 48);
    }

hashJob("password test").then((value) {
          hashedPassword = value;
          print(hashedPassword);
        }); 

工作演示

​

​

输出

I/flutter ( 9820): 2020-02-20 09:06:53.904373
I/flutter ( 9820): 2020-02-20 09:06:54.559547
I/flutter ( 9820): 2020-02-20 09:06:54.560054
I/flutter ( 9820): J434csHIYPm0NfSJJolyuq6ykTF+x3sswIi/x9ayMAxTTE63fG63BndBCafIgN6w
I/flutter ( 9820): J434csHIYPm0NfSJJolyuq6ykTF+x3sswIi/x9ayMAxTTE63fG63BndBCafIgN6w
I/flutter ( 9820): J434csHIYPm0NfSJJolyuq6ykTF+x3sswIi/x9ayMAxTTE63fG63BndBCafIgN6w

全码

import 'package:flutter/material.dart';
import 'package:steel_crypt/steel_crypt.dart';
import 'dart:async';
import 'package:flutter/foundation.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget { 
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(      
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

Future<String> hashJob(String password) async {
  return compute(hashPassword, password);
}

String hashPassword(String password) {
  return PassCrypt().hashPass("", password, 48);
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  String hashedPassword;

  void _incrementCounter() {
    /*print(DateTime.now());
    var passHash = PassCrypt().hashPass("", "password test", 48);
    print(DateTime.now());
    print(passHash);*/

    print(DateTime.now());
    hashJob("password test").then((value) {
      hashedPassword = value;
      print(hashedPassword);
    });

    print(DateTime.now());
    setState(() {     
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {   
    return Scaffold(
      appBar: AppBar(        
        title: Text(widget.title),
      ),
      body: Center(       
        child: Column(          
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), 
    );
  }
}