Flutter 中的 401 未授权错误，但在 Postman 中工作正常

Question

I have Laravel endpoints. Login, Register and Home(where getData() will be working).

the register API and Login API is working fine but the problem is with the HomePage API where it will not ask for user details, it's a get method where it will return the details upon checking whether the user is logged-In or not.

  var token;

  _getKey() async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    token = prefs.getString('key');
    print("this is Key $token");
  }
saveKey(String key) async {
    SharedPreferences prefs = await SharedPreferences.getInstance();
    prefs.setString('key', key);
  }
  getData() async {
    await _getCSRF();
    await _getKey();
    print(_setAuthHeaders());
    String uri = "$baseUrlUser/user_bal";
    try {
      return await http.get(Uri.parse(uri), headers: _setAuthHeaders());
    } catch (e) {
      return e;
    }
  }

  _setAuthHeaders() => {
        'Accept': 'application/json',
        'Connection': 'keep-alive',
        'Authorization': 'Bearer $token',
      };

A token is printing here:

result of hitting the endpoint in the browser.

Please help.

Answer 1

please pass token as

'Authorization': 'Bearer $token;',

Answer 2

 _setAuthHeaders() => {
        'Accept': 'application/json',
        'Connection': 'keep-alive',
        'Authorization': 'Bearer $token',
      };

Answer 3

http library automatically converts the header name to lower-case, may your server not accepting lower-case header name. Follow this step:

1. Find io_client.dart in External Libraries->Dart Packages->http-x.xx->src->io_client.dart
2. Find this code inside io_client.dart (line 40)

request.headers.forEach((name, value) {
  ioRequest.headers.set(name, value);
});

3. Add preserveHeaderCase: true

request.headers.forEach((name, value) {
  ioRequest.headers.set(name, value,preserveHeaderCase:true);
});

4. Clean your project and rebuild

Answer 4

If you are making flutter web project then please check at Inspect >> Console, that Refused to set unsafe header "content-length" is printing or not. If its happening then in your code where you have api setup

class ApiServiceProvider extends GetConnect {}

@override
  void onInit() {
    if (kIsWeb) {
      httpClient.addRequestModifier<void>((request) {
        request.headers.remove('user-agent');
        request.headers.remove('content-length');
        return request;
      });
    }
    super.onInit();
  }