Flutter + AWS: It always gives broken pipe error - amazon-web-services

Question

I'm trying to compare faces with AWS rekognition API. but somehow I'm getting "broken pipe" error all the time. There is no problem on aws keys and photos. I'm trying to get more info from http.post but It just says "broken pipe", it doesn't give any detail, unfortunately.
Scenario;
User takes 2 photos (working)
on second taken, I will parse images to bytes (working)
send bytes with standard request to aws API (doesn't work)
I changed the image quality to the lowest as well, but It didn't help.
Main.dart code
import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:camera/camera.dart';
import 'testa.dart';
import 'package:path_provider/path_provider.dart';
List<CameraDescription> cameras;
Future<void> main() async {
cameras = await availableCameras();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
CameraController controller;
#override
void initState() {
super.initState();
controller = CameraController(cameras[0], ResolutionPreset.low);
controller.initialize().then((_) {
if (!mounted) {
return;
}
setState(() {});
});
}
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
Future<String> _checkImage(String filePath, String secondPath) async {
File sourceImagefile, targetImagefile; //load source and target images in those File objects
String accessKey, secretKey, region ; //load your aws account info in those variables
print(filePath);
print(secondPath);
targetImagefile = File(filePath);
sourceImagefile = File(secondPath);
print(targetImagefile.existsSync());
print(sourceImagefile.existsSync());
accessKey = '';
secretKey = '';
region = 'eu-west-1';
RekognitionHandler rekognition = new RekognitionHandler(accessKey, secretKey, region);
String labelsArray = await rekognition.compareFaces(sourceImagefile, targetImagefile);
return labelsArray;
}
Widget cameraPart() {
if (!controller.value.isInitialized) {
return Container();
}
return AspectRatio(
aspectRatio:
controller.value.aspectRatio,
child: CameraPreview(controller));
}
#override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: cameraPart(),
floatingActionButton: FloatingActionButton(
onPressed: takePhoto,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
Future<String> get360PhotoFolder() async {
final Directory appFolder = await getAppFolder();
final String dirPath = '${appFolder.path}/photos360';
await Directory(dirPath).create(recursive: true);
return dirPath;
}
String firstPath = '';
String secondPath = '';
Future<bool> takePhoto() async {
final String dirPath = await get360PhotoFolder();
final String filePath = '$dirPath/${timestamp()}_test.jpg';
try {
debugPrint('photo taken - $filePath');
await controller.takePicture(filePath);
setState(() {
if (firstPath == '') {
print('a');
firstPath = filePath;
}else if (secondPath == '') {
print('b');
secondPath = filePath;
_checkImage(firstPath, secondPath).then((value) {
print(value);
}).catchError((error) {
print(error);
});
firstPath = '';
secondPath = '';
}
});
} on CameraException catch (e) {
print([e.code, e.description]);
return true;
}
return false;
}
String timestamp() => DateTime.now().millisecondsSinceEpoch.toString();
Future<Directory> getAppFolder() async =>
await getApplicationDocumentsDirectory();
}
AWS rekognition code
import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'package:intl/intl.dart';
import 'testb.dart';
class RekognitionHandler {
final String _accessKey, _secretKey, _region;
RekognitionHandler(this._accessKey, this._secretKey, this._region);
Future<String> _rekognitionHttp(String amzTarget, String body) async {
String endpoint = "https://rekognition.$_region.amazonaws.com/";
String host = "rekognition.$_region.amazonaws.com";
String httpMethod = "POST";
String service = "rekognition";
var now = new DateTime.now().toUtc();
var amzFormatter = new DateFormat("yyyyMMdd'T'HHmmss'Z'");
String amzDate =
amzFormatter.format(now); // format should be '20170104T233405Z"
var dateFormatter = new DateFormat('yyyyMMdd');
String dateStamp = dateFormatter.format(
now); // Date w/o time, used in credential scope. format should be "20170104"
int bodyLength = body.length;
String queryStringParamters = "";
Map<String, String> headerParamters = {
"content-length": bodyLength.toString(),
"content-type": "application/x-amz-json-1.1",
"host": host,
"x-amz-date": amzDate,
"x-amz-target": amzTarget
};
String signature = Signature.generateSignature(
endpoint,
service,
_region,
_secretKey,
httpMethod,
now,
queryStringParamters,
headerParamters,
body);
String authorization =
"AWS4-HMAC-SHA256 Credential=$_accessKey/$dateStamp/$_region/$service/aws4_request, SignedHeaders=content-length;content-type;host;x-amz-date;x-amz-target, Signature=$signature";
headerParamters.putIfAbsent('Authorization', () => authorization);
//String labelsArray = "";
StringBuffer builder = new StringBuffer();
try {
HttpClient httpClient = new HttpClient();
httpClient.connectionTimeout = Duration(minutes: 10);
HttpClientRequest request = await httpClient.postUrl(Uri.parse(endpoint));
request.headers.set('content-length', headerParamters['content-length']);
request.headers.set('content-type', headerParamters['content-type']);
request.headers.set('host', headerParamters['host']);
request.headers.set('x-amz-date', headerParamters['x-amz-date']);
request.headers.set('x-amz-target', headerParamters['x-amz-target']);
request.headers.set('Authorization', headerParamters['Authorization']);
request.write(body);
HttpClientResponse response = await request.close();
await for (String a in response.transform(utf8.decoder)) {
builder.write(a);
}
} catch (e) {
print(e);
}
return Future.value(builder.toString());
}
Future<String> compareFaces(
File sourceImagefile, File targetImagefile) async {
try {
List<int> sourceImageBytes = sourceImagefile.readAsBytesSync();
String base64SourceImage = base64Encode(sourceImageBytes);
List<int> targetImageBytes = targetImagefile.readAsBytesSync();
String base64TargetImage = base64Encode(targetImageBytes);
String body =
'{"SourceImage":{"Bytes": "$base64SourceImage"},"TargetImage":{"Bytes": "$base64TargetImage"}}';
String amzTarget = "RekognitionService.CompareFaces";
String response = await _rekognitionHttp(amzTarget, body);
return response;
} catch (e) {
print(e);
return "{}";
}
}
}