Dio not properly following redirects and returning incorrect response bodies

[2x2xplz]

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Issue Info

Info	Value
Platform Name	flutter
Platform Version
Dio Version	3.0.7
Android Studio / Xcode Version	IntelliJ 2020.1
Repro rate	all the time (100%)
Repro with our demo prj
Demo project link	see below

Issue Description and Steps

I am using Dio in a Flutter app and as part of testing, I was using the examples at https://the-internet.herokuapp.com/

I've noticed that whether or not I use the correct credentials to log into https://the-internet.herokuapp.com/login, the Dio response data is the same. It doesn't appear to see the login results message, nor does it go to the "secure" page upon a successful login.

Postman returns the correct HTML response, you can also view it correctly in Chrome DevTools or simple View Source. However Dio is unable to get the correct response (the Dart http package also returns incorrect response bodies).

The POST to "authenticate" returns a 303 redirect to either the "login" page again or to a "secure" page if successful. Dio only goes back to the login page (even with correct credentials) and does not include the "invalid credentials" message from the page source. The site does not use AJAX or require an additional HTTP call to get the login status, so that's not the issue.

My full test is:

import 'package:dio/dio.dart';
import 'package:http/http.dart' as http;
import 'package:flutter_test/flutter_test.dart';


void main() {

  test('dio test', () async {

  test('dio test', () async {

    Dio dio = Dio();
    Response responseGET = await dio.get("https://the-internet.herokuapp.com/login");
    // should redirect back to login page, with invalid credentials message
    Response responsePOSTfail = await dio.post("https://the-internet.herokuapp.com/authenticate",
                                      data: {"username": "tomsmith", "password": "badpassword"},
                                      options: Options(contentType:Headers.formUrlEncodedContentType ));
    // should redirect to secure page, with success message and different content
    Response responsePOSTsuccess = await dio.post("https://the-internet.herokuapp.com/authenticate",
                                      data: {"username": "tomsmith", "password": "SuperSecretPassword!"},
                                      options: Options(contentType:Headers.formUrlEncodedContentType ));

    http.Response responseHTTP = await http.post("https://the-internet.herokuapp.com/authenticate",
                                      body: {"username": "tomsmith", "password": "SuperSecretPassword!"});

    // all 3 tests fail. all the responses should be different but they are all the same
    // expect(responseGET.data.toString(), isNot(equals(responsePOSTfail.data.toString())));
    expect(responseGET.data.toString(), isNot(equals(responsePOSTsuccess.data.toString())));
    // expect(responseGET.data.toString(), isNot(equals(responseHTTP.body)));

  });

}

Thanks very much!

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If this is still an issue, please make sure it is up to date and if so, add a comment that this is still an issue to keep it open. Thank you for your contributions.

[2x2xplz]

This is not stale, the issue remains and is unresolved. Thank you.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If this is still an issue, please make sure it is up to date and if so, add a comment that this is still an issue to keep it open. Thank you for your contributions.

[2x2xplz]

Again, the issue is unresolved. Thank you.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If this is still an issue, please make sure it is up to date and if so, add a comment that this is still an issue to keep it open. Thank you for your contributions.

[shinobu-uwu]

Any progress on this issue?

[dipak-pd]

Does it not support redirect?