When using Dio in a web environment, there needs to be a way to disable Dio’s automatic cookie setting about dio

[AlexV525]

I wish it can help someone who are under same issues and I also wish this can help you, author, to develop this lovable library. (deeply appreciate your efforts) Still wonder why and how but anyway It is solved...

See https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#simple_requests which defines the list of content-type which could be treated as simple requests.

[AlexV525]

https://pub.dev/documentation/dio/latest/browser/BrowserHttpClientAdapter/withCredentials.html

[momadvisor]

https://pub.dev/documentation/dio/latest/browser/BrowserHttpClientAdapter/withCredentials.html

Thanks. But Its default value is false. And even when I set it false, It occurs an same error. I think the 'Origin' header should not exist.

dioClient.options.extra['withCredentials'] = false;

This is an error message on the chrome console.
Access to XMLHttpRequest at 'https://api.xxx.com/' from origin 'http://localhost:10545' 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.

[AlexV525]

Then it should not related to Cookies. The request itself might considered CORS.

[momadvisor]

I wonder why It can be resolved just by replacing dio client with http library? Maybe, doesn't http library set the Origin header?(Maybe, in contrast, dio client sets the Origin header)

[momadvisor]

Yea. you're right. After more debugging, I found the problem was not related to cookies, but to header fields. But until now, I couldn't find exactly and specifically which is a problem and how to solve it

[AlexV525]

Maybe #2125 (comment)

[momadvisor]

After removing 'contentType' property, It is solved.

dio: 5.4.2+1
flutter: 3.19.2
chrome: 124.0.6367.61 (windows 10)

BEFORE

final client = Dio(
    BaseOptions(
      baseUrl: 'https://api.xxx.com/',
      connectTimeout: const Duration(seconds: 5),
      receiveTimeout: const Duration(seconds: 10),
      headers: {
        HttpHeaders.userAgentHeader: ua,
      },
      contentType: Headers.jsonContentType,
      responseType: ResponseType.json,
    ),
  );

AFTER

final client = Dio(
    BaseOptions(
      baseUrl: 'https://api.xxx.com/',
      connectTimeout: const Duration(seconds: 5),
      receiveTimeout: const Duration(seconds: 10),
      headers: {
        HttpHeaders.userAgentHeader: ua,
      },
      // remove this property
      //contentType: Headers.jsonContentType,
      responseType: ResponseType.json,
    ),
  );

I wish it can help someone who are under same issues and I also wish this can help you, author, to develop this lovable library. (deeply appreciate your efforts)
Still wonder why and how but anyway It is solved...