如何在 Flutter For Web 上发起 HTTP 请求?
How to make HTTP Requests on Flutter For Web?
我正在构建一个向 NodeJS 服务器执行 HTTP 请求的应用程序,但是当我执行 HTTP 请求时,结果如下:
Access to XMLHttpRequest at 'http://127.0.0.1:8000/' from origin 'http://127.0.0.1:8080' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
和
Uncaught (in promise) Error: XMLHttpRequest error.
dart:sdk_internal 41864:30 get current
package:http/src/packages/http/src/browser_client.dart 84:22 <fn>
dart:sdk_internal 99587:96 <fn>
at Object.dart.createErrorWithStack (dart_sdk.js:4617)
at Object.async._rethrow (dart_sdk.js:28723)
at async._AsyncCallbackEntry.new.callback (dart_sdk.js:28719)
at Object.async._microtaskLoop (dart_sdk.js:25352)
at async._startMicrotaskLoop (dart_sdk.js:25358)
at dart_sdk.js:25433
这是我使用 'package:http/http.dart' as http;
发出 HTTP 请求的代码:
void requestGet(String endpoint, Callback cb) async {
return await http.get(Uri.encodeFull(url + endpoint),
headers: {"Accept": "application/json"}).then((http.Response response) {
print(response.body);
});
}
void requestPost(String endpoint, Map data, Callback cb) async {
return await http.post(Uri.encodeFull(url + endpoint),
body: data,
headers: {"Accept": "application/json"}).then((http.Response response) {
print(response.body);
});
}
通过在我的 NodeJS 服务器中启用 CORS 解决了保护 HTTP 请求的问题 here 是文档。
如果您正在使用 PHP。
将以下代码添加到您的 .htaccess 文件(位于根文件夹中)
<ifModule mod_headers.c>
SetEnvIf Origin "http(s)?://(www.)?(localhost:CHANGE_THIS_WITH_PORT_NUMBER|somedomain.com)$" AccessControlAllowOrigin=[=10=]
Header add Access-Control-Allow-Origin %{AccessControlAllowOrigin}e env=AccessControlAllowOrigin
Header always set Access-Control-Allow-Methods: "GET,POST,PUT,DELETE,OPTIONS"
</ifModule>
我正在构建一个向 NodeJS 服务器执行 HTTP 请求的应用程序,但是当我执行 HTTP 请求时,结果如下:
Access to XMLHttpRequest at 'http://127.0.0.1:8000/' from origin 'http://127.0.0.1:8080' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
和
Uncaught (in promise) Error: XMLHttpRequest error.
dart:sdk_internal 41864:30 get current
package:http/src/packages/http/src/browser_client.dart 84:22 <fn>
dart:sdk_internal 99587:96 <fn>
at Object.dart.createErrorWithStack (dart_sdk.js:4617)
at Object.async._rethrow (dart_sdk.js:28723)
at async._AsyncCallbackEntry.new.callback (dart_sdk.js:28719)
at Object.async._microtaskLoop (dart_sdk.js:25352)
at async._startMicrotaskLoop (dart_sdk.js:25358)
at dart_sdk.js:25433
这是我使用 'package:http/http.dart' as http;
发出 HTTP 请求的代码:
void requestGet(String endpoint, Callback cb) async {
return await http.get(Uri.encodeFull(url + endpoint),
headers: {"Accept": "application/json"}).then((http.Response response) {
print(response.body);
});
}
void requestPost(String endpoint, Map data, Callback cb) async {
return await http.post(Uri.encodeFull(url + endpoint),
body: data,
headers: {"Accept": "application/json"}).then((http.Response response) {
print(response.body);
});
}
通过在我的 NodeJS 服务器中启用 CORS 解决了保护 HTTP 请求的问题 here 是文档。
如果您正在使用 PHP。 将以下代码添加到您的 .htaccess 文件(位于根文件夹中)
<ifModule mod_headers.c>
SetEnvIf Origin "http(s)?://(www.)?(localhost:CHANGE_THIS_WITH_PORT_NUMBER|somedomain.com)$" AccessControlAllowOrigin=[=10=]
Header add Access-Control-Allow-Origin %{AccessControlAllowOrigin}e env=AccessControlAllowOrigin
Header always set Access-Control-Allow-Methods: "GET,POST,PUT,DELETE,OPTIONS"
</ifModule>