在Dartpad中如何使用http.Request实现Basic Auth请求？

我在Dartpad中向https://httpbin.org/basic-auth发起Basic Auth请求时，http.get()方法可以成功实现，但使用http.Request()类时遇到编译错误：

• 尝试request.headers(authHeader)时，报错：'headers' isn't a function or method and can't be invoked.
• 尝试request.headers = authHeader时，报错：The setter 'headers' isn't defined for the class 'Request'.

原来可用的http.get()代码：

import 'dart:convert' as convert;
import 'package:http/http.dart' as http;

void main(List<String> arguments) async {

  final url_httpbin = Uri.https('httpbin.org', '/basic-auth/myuser/mypasswd');  
  
  var base64Encoder = convert.Base64Encoder(); 
  var creds64 = base64Encoder.convert('myuser:mypasswd'.codeUnits);
  Map<String, String> authHeader = {'Authorization':'Basic $creds64'};  
    
  final response = await http.get(url_httpbin, 
       headers: authHeader); // sending headers with basic auth

  if (response.statusCode == 200) {
    final jsonResponse = convert.jsonDecode(response.body);
    print('Response $jsonResponse');
  } else {
    print('Request failed with status: ${response.statusCode}.');
  }
}

错误原因 #

http.Request的headers属性是HttpHeaders类型，而非普通的Map<String, String>，所以不能直接赋值，也不能作为方法调用。需要通过HttpHeaders提供的方法来添加头部信息。

正确实现代码 #

import 'dart:convert' as convert;
import 'package:http/http.dart' as http;

void main(List<String> arguments) async {
  final url_httpbin = Uri.https('httpbin.org', '/basic-auth/myuser/mypasswd');
  
  // 创建Request实例
  var request = http.Request('GET', url_httpbin);
  
  // 方式1：通过addAll添加头部Map
  var base64Encoder = convert.Base64Encoder(); 
  var creds64 = base64Encoder.convert('myuser:mypasswd'.codeUnits);
  Map<String, String> authHeader = {'Authorization':'Basic $creds64'};
  request.headers.addAll(authHeader);
  
  // 方式2：直接使用HttpHeaders的authorization方法（更简洁）
  // request.headers.authorization = 'Basic $creds64';

  // 创建Client并发送请求
  var client = http.Client();
  try {
    var streamedResponse = await client.send(request);
    var response = await http.Response.fromStream(streamedResponse);
    
    if (response.statusCode == 200) {
      final jsonResponse = convert.jsonDecode(response.body);
      print('Response $jsonResponse');
    } else {
      print('Request failed with status: ${response.statusCode}.');
    }
  } finally {
    client.close();
  }
}

关键说明 #

• http.Request的headers是HttpHeaders对象，需用addAll()方法传入Map<String, String>来批量添加头部，或者直接调用HttpHeaders的属性（如authorization）设置单个头部。
• 创建Request后，需要通过http.Client的send()方法发送请求，得到StreamedResponse，再转换为Response处理响应内容。
• 记得在请求完成后关闭Client，避免资源泄漏，最好用try/finally包裹。

内容的提问来源于stack exchange，提问作者surfmuggle