使用枕头调整上载到s3的图像的大小

Question

我有一个import 'package:flutter/material.dart'; import 'dart:async'; void main() { runApp(MyApp()); } class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( primarySwatch: Colors.blue, visualDensity: VisualDensity.adaptivePlatformDensity, ), home: MyHomePage(title: 'Flutter Demo Home Page'), ); } } 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; StreamController<int> _events; @override initState() { super.initState(); _events = new StreamController<int>(); _events.add(60); } Timer _timer; void _startTimer() { _counter = 60; if (_timer != null) { _timer.cancel(); } _timer = Timer.periodic(Duration(seconds: 1), (timer) { //setState(() { (_counter > 0) ? _counter-- : _timer.cancel(); //}); print(_counter); _events.add(_counter); }); } void alertD(BuildContext ctx) { var alert = AlertDialog( // title: Center(child:Text('Enter Code')), shape: RoundedRectangleBorder( borderRadius: BorderRadius.all(Radius.circular(20.0))), backgroundColor: Colors.grey[100], elevation: 0.0, content: StreamBuilder<int>( stream: _events.stream, builder: (BuildContext context, AsyncSnapshot<int> snapshot) { print(snapshot.data.toString()); return Container( height: 215, child: Column( crossAxisAlignment: CrossAxisAlignment.center, children: <Widget>[ Padding( padding: const EdgeInsets.only( top: 10, left: 10, right: 10, bottom: 15), child: Text( 'Enter Code', style: TextStyle( color: Colors.green[800], fontWeight: FontWeight.bold, fontSize: 16), )), Container( height: 70, width: 180, child: TextFormField( style: TextStyle( fontSize: 20, fontWeight: FontWeight.bold), textAlign: TextAlign.center, decoration: InputDecoration( enabledBorder: OutlineInputBorder( borderSide: BorderSide(color: Colors.green, width: 0.0)), ), keyboardType: TextInputType.number, maxLength: 10, ), ), SizedBox( height: 1, ), Text('00:${snapshot.data.toString()}'), SizedBox( height: 15, ), Row( mainAxisAlignment: MainAxisAlignment.spaceBetween, children: <Widget>[ ClipRRect( borderRadius: BorderRadius.circular(25), child: Material( child: InkWell( onTap: () { //Navigator.of(ctx).pushNamed(SignUpScreenSecond.routeName); }, child: Container( width: 100, height: 50, decoration: BoxDecoration( borderRadius: BorderRadius.circular(25), gradient: LinearGradient( colors: [ Colors.green, Colors.grey, ], begin: Alignment.topLeft, end: Alignment.bottomRight), ), child: Center( child: Text( 'Validate', style: TextStyle( color: Colors.white, fontSize: 16, fontWeight: FontWeight.bold), )), ), ), ), ), ClipRRect( borderRadius: BorderRadius.circular(25), child: Material( child: InkWell( onTap: () {}, child: Container( width: 100, height: 50, decoration: BoxDecoration( borderRadius: BorderRadius.circular(25), gradient: LinearGradient( colors: [ Colors.grey, Colors.green, ], begin: Alignment.topLeft, end: Alignment.bottomRight), ), child: Center( child: Text( 'Resend', style: TextStyle( color: Colors.white, fontSize: 16, fontWeight: FontWeight.bold), )), ), ), ), ) ], ), //new column child ], ), ); })); showDialog( context: ctx, builder: (BuildContext c) { return alert; }); } void _incrementCounter() { setState(() { _counter++; }); } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(widget.title), ), body: Center( child: Column( mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ RaisedButton( onPressed: () { _startTimer(); alertD(context); }, child: Text('Click')), Text( 'You have pushed the button this many times:', ), Text( '$_counter', style: Theme.of(context).textTheme.headline4, ), ], ), ), floatingActionButton: FloatingActionButton( onPressed: _incrementCounter, tooltip: 'Increment', child: Icon(Icons.add), ), ); } } ，它具有定义的chalice application，将使用s3事件通知来触发。每次在我的s3存储桶中创建图像时，都会调用lambda_handler函数来创建缩略图。但是，当您使用lambda_handler将图像上传到s3时，上传的文件没有文件扩展名。

s3上的文件如下：

现在，当使用枕头时，会引发错误presigned_urls。

我应该怎么做？

Answer 1

您可以使用负责执行图像上传的功能吗？

如果您使用预先签名的帖子执行图像上传，则还应该在object_name参数中指定文件扩展名。

   response = s3_client.generate_presigned_post(BUCKET_NAME,
                                                "5eafba9fa31dd3bcc190a52.jpg",
                                                Fields=fields,
                                                Conditions=conditions,
                                                ExpiresIn=expiration)

这将导致图像以适当的扩展名上传，因此允许任何后续调用具有适当的文件扩展名。

如果您只能访问圣杯应用程序，并且可以保证文件扩展名总是属于类型，则可以在使用Pillow之前附加扩展名。