我一直在遵循本教程来构建使用Cloud AutoML的Flutter应用程序：https://medium.com/@epynic/using-automl-vision-in-your-next-flutter-app-3cc436312443 。我使用Google Cloud创建了一个VM实例，该应用程序应该向该实例上的php文件发送一个http POST请求，并且该PHP文件将充当与AutoML Vision进行交互的代理。但是，当我从flutter应用程序发出http请求时，状态代码为500。
这是automl.php文件的代码（出于安全原因，URL的某些部分被隐藏了）：
<?php
$image = $_POST['image'];
$key = trim(shell_exec('sudo -u FlutterServiceAccount gcloud auth application-default print-access-token 2<&1')); // replace service_name with your service account name
$post = '{"payload":{"image":{"imageBytes": "' . $image . '"}}}';
$curl = curl_init();
// The REST API URL can be found from the predict tab example replace with your account URL https://automl.googleapis.com/v1beta1/projects/quizappflutter/locations/us-central1/models/ICNXXXXXXXXXX41:predict
curl_setopt_array($curl, array(
CURLOPT_URL => "https://automl.googleapis.com/v1beta1/projects/103XXXXXXXXXX/locations/us-central1/models/ICN49XXXXXXXXXXXX:predict",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => $post,
CURLOPT_HTTPHEADER => array(
"Authorization: Bearer $key",
"Content-Type: application/json",
),
));
$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);
if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}
这是flutter应用程序的main.dart代码
import 'dart:convert';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:image_picker/image_picker.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: 'QuizApp Solver'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
File _image;
bool predictionStarted = false;
bool predictionComplete = false;
var predictionResult = 'Please wait....';
Future getImage() async {
setState(() {
predictionStarted = false;
predictionComplete = false;
});
// var image = await ImagePicker.pickImage(source: ImageSource.camera);
var image = await ImagePicker.pickImage(source: ImageSource.gallery);
setState(() {
_image = image;
predictionStarted = true;
});
//post image
List<int> imageBytes = image.readAsBytesSync();
String base64Image = base64.encode(imageBytes);
print(base64Image);
Map<String, String> headers = {"Accept": "application/json"};
Map body = {"image": base64Image};
//
var response = await http.post('http://35.XXX.XXX.XXX/automl.php',
body: body, headers: headers);
print('Status code');
print(response.statusCode);
setState(() {
predictionResult = response.body;
predictionComplete = true;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: SingleChildScrollView(
child: Column(
children: <Widget>[
SizedBox(
height: 20,
),
Text(
'Push the camera button',
textAlign: TextAlign.center,
),
RaisedButton(
onPressed: getImage,
child: Text('Camera'),
),
(_image != null)
? Image.file(
_image,
scale: 20,
)
: Text('No Image Picked'),
predictionBody()
],
),
),
);
}
Widget predictionBody() {
var predictionText = (predictionComplete) ? 'Result' : 'Prediction started';
if (predictionStarted) {
return Column(
children: <Widget>[
Divider(),
Text(predictionText),
Text(predictionResult)
],
);
} else {
return Container();
}
}
}
pubspec.yaml
name: awsquizsolver
description: A new Flutter project.
# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1
environment:
sdk: ">=2.1.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^0.1.2
image_picker: ^0.6.0+2
http: ^0.12.0+2
dev_dependencies:
flutter_test:
sdk: flutter
# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec
# The following section is specific to Flutter.
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
# assets:
# - images/a_dot_burr.jpeg
# - images/a_dot_ham.jpeg
# An image asset can refer to one or more resolution-specific "variants", see
# https://flutter.io/assets-and-images/#resolution-aware.
# For details regarding adding assets from package dependencies, see
# https://flutter.io/assets-and-images/#from-packages
# To add custom fonts to your application, add a fonts section here,
# in this "flutter" section. Each entry in this list should have a
# "family" key with the font family name, and a "fonts" key with a
# list giving the asset and other descriptors for the font. For
# example:
# fonts:
# - family: Schyler
# fonts:
# - asset: fonts/Schyler-Regular.ttf
# - asset: fonts/Schyler-Italic.ttf
# style: italic
# - family: Trajan Pro
# fonts:
# - asset: fonts/TrajanPro.ttf
# - asset: fonts/TrajanPro_Bold.ttf
# weight: 700
#
# For details regarding fonts from package dependencies,
# see https://flutter.io/custom-fonts/#from-packages
谢谢。