Dart发送GET请求返回空数组，Postman可正常获取数据求助

我是Dart新手，遇到一个奇怪的问题——用Dart发送GET请求时返回空数组，但用Postman发送完全相同的请求却能正常获取数据。我尝试模仿Postman生成的代码调试，但问题依然存在，恳请帮忙排查两者的差异原因。

我的Dart代码 #

void loadData() async {
  showLoading(context);
  try {
    hideDialog(context);
    // String url = 'http://127.0.0.1:5000';
    String url = '127.0.0.1:5000';
    String endpoint = '/carrier_loadboard';
    String option = 'Market';
    String orgId = '2';

    final queryParameters = {
      'option': option,
      'org_id': orgId,
    };

    final headers = {
      'Authorization': 'Bearer$userToken',
      'Content-Type': 'application/json',
      'Cookie': 'session=$sessionCookie',
    };

    var creds = json.encode({
      'email': 'carrier@domain.com',
      'password': 'thePassword',
    });

    final uri = Uri.http(url, endpoint, queryParameters);
    final response = await get(uri, headers: headers);

    // var request = Request(
    //     'GET',
    //     Uri.parse(
    //         'http://127.0.0.1:5000/carrier_loadboard?option=Market&org_id=2'));
    // request.body = creds;
    // request.headers.addAll(headers);

    // StreamedResponse response = await request.send();

    if (response.statusCode == 200) {
      // print(await response.stream.bytesToString());
      print('Load data success');
      List data = json.decode(response.body);
      print(data);
      if (data.isEmpty) {
        print('No data');
      }
    } else {
      print(response.reasonPhrase);
      print('Load data failed');
    }
  } catch (e) {
    devlog.log(e.toString());
  }
}

Postman生成的可正常运行代码 #

var headers = {
  'Authorization': 'Bearer tokenTokenToken',
  'Content-Type': 'application/json',
  'Cookie': 'session=.cookieCodeCookieCode'
};
var request = http.Request('GET', Uri.parse('http://127.0.0.1:5000/carrier_loadboard?option='Market'&org_id='2''));
request.body = '''// {"email": "carrier@domain.com", "password":"thePassword"}\n''';
request.headers.addAll(headers);

http.StreamedResponse response = await request.send();

if (response.statusCode == 200) {
  print(await response.stream.bytesToString());
}
else {
  print(response.reasonPhrase);
}

响应结果对比 #

• Dart请求响应结果：

[]

• Postman请求响应结果（仅展示第一个对象）：

[
    {
        "agent_id": null,
        "assigned_carrier_id": null,
        "carrier_org_id": 2,
        "commodity": null,
        "deliver_address": "700 4th St, San Francisco, CA 94107, USA",
        "deliver_appt": null,
        "deliver_appt_required": false,
        "deliver_date": "2021-10-22T17:46:00",
        "deliver_from_date": "2022-03-12T00:00:00",
        "deliver_to_date": null,
        "driver_id": null,
        "expected_delivery_bid": "1000",
        "expected_posting_bid": "1300",
        "id": 104,
        "load_num_broker": null,
        "load_num_carrier": null,
        "load_num_shipper": null,
        "margin": null,
        "notes": null,
        "office_hr_end": null,
        "office_hr_start": null,
        "org_created": null,
        "org_id_posted": 1,
        "org_id_reposted": 1,
        "org_name": null,
        "pickup_address": "801 Alaskan Way, Seattle, WA 98104, USA",
        "pickup_appt": null,
        "pickup_appt_required": false,
        "pickup_date": "2021-10-18T17:46:00",
        "pickup_from_date": "2022-03-12T00:00:00",
        "pickup_to_date": null,
        "po_num": null,
        "poster_id": null,
        "shipper_id": null,
        "status": "Completed",
        "time_accepted": null,
        "time_posted": "2021-10-19T00:47:24.060521",
        "trailer_id": null,
        "trailer_type": "Double",
        "truck_id": "",
        "weight": "1000"
    }
]

排查要点 #

• Authorization头的空格问题：你的Dart代码中Authorization头是'Bearer$userToken'，而Postman里是'Bearer tokenTokenToken'——注意Bearer和token之间有一个空格。服务器解析token时，可能会把Bearerxxx当成无效token，导致权限验证不通过，返回空数组。把Dart代码里的这行改成'Bearer $userToken'（加空格）试试。
• GET请求的body差异：Postman的代码给GET请求添加了body（包含邮箱密码），但标准HTTP规范中GET请求通常不携带body，不过有些服务器会特殊处理这种情况。你当前用Dart的get方法发送请求，这个方法不支持设置body；而你注释掉的Request方式是可以设置body的，和Postman的逻辑一致。可以尝试启用注释的代码，用Request方式发送请求，看是否能拿到数据。
• 确认Token和Cookie的正确性：检查userToken和sessionCookie的实际值是否和Postman中使用的完全一致，有没有在拼接时出现截断、拼写错误等问题。比如session=$sessionCookie是否正确拼接了完整的cookie值。
• URL验证：虽然Uri.http('127.0.0.1:5000', ...)生成的URL应该和Postman的一致，但可以打印uri.toString()确认最终请求的URL是否和Postman里的完全相同，避免query参数拼接错误。

内容的提问来源于stack exchange，提问作者KurtReyn