Flutter HTTP 包没有响应

Question

我正在尝试从我制作的 API 中获取数据（使用 python）到我的 Flutter 网站，但是我在其中请求 API 响应的代码块不是运行。我尝试了我所知道的一切，但它给出的错误很奇怪。

Here is the code I'm getting error in :

import 'package:http/http.dart' ;
import 'dart:convert';

const String url = 'http://localhost:5000/api?imagenumber=' ;

Future getImageIds(int image) async {

  Response response = await get( url + image.toString()) ;
  dynamic responsBody = response.body ;
  dynamic decodedData = jsonDecode(responsBody) ;
  return  decodedData ;
}

顺便说一句，API 在本地主机上是运行（当前）。

And here is the error:

Performing hot restart...
Syncing files to device Chrome...
Restarted application in 605ms.
This if from screen 1: 1 , 2 , 3
Error: XMLHttpRequest error.
    C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/core_patch.dart 906:28                get current
packages/http/src/browser_client.dart 84:22                                                                                    <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/zone.dart 1450:54                                              runUnary
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 143:18                                        handleValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 696:44                                        handleValueCallback
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 725:32                                        _propagateToListeners
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 519:7                                         [_complete]
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream_pipe.dart 61:11                                         _cancelAndValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream.dart 1302:7                                             <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 324:14  _checkAndCall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 329:39  dcall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/html/dart2js/html_dart2js.dart 37312:58                              <fn>


    at Object.createErrorWithStack (http://localhost:55081/dart_sdk.js:4361:12)
    at Object._rethrow (http://localhost:55081/dart_sdk.js:38188:16)
    at async._AsyncCallbackEntry.new.callback (http://localhost:55081/dart_sdk.js:38182:13)
    at Object._microtaskLoop (http://localhost:55081/dart_sdk.js:38014:13)
    at _startMicrotaskLoop (http://localhost:55081/dart_sdk.js:38020:13)
    at http://localhost:55081/dart_sdk.js:33517:9

忽略前四行

Answer 1

您需要 Cross-Origin 启用资源共享 (CORS) 才能发出请求。如果启用了 CORS，您将不会再收到此错误。我遇到了同样的问题，决定只通过云功能发出请求。您可以查看启用 cors，可能还有一种方法可以在 Google chrome.

中启用它进行测试

添加：

<IfModule mod_headers.c>
   Header set Access-Control-Allow-Origin "*"
</IfModule>

到您的服务器.htaccess

Flutter HTTP 包没有响应

Flutter HTTP package is not responding

api

http

package

web-deployment

flutter