在flutter http请求中为所有请求设置默认标头的最佳方法

Posted 2023-02-23

【中文标题】在flutter http请求中为所有请求设置默认标头的最佳方法

【英文标题】：Best way to set default header for all request in flutter http request

【发布时间】：2019-06-16 16:18:21

【问题描述】：

对不起，如果这个问题太简单了，但我是新手，最近找不到在 HTTP 请求中设置默认标头的好方法，我可以扩展类或为其包装一个函数，但不应该有一种内置的简单方法，但我在文档中找不到它。

【参考方案1】：

这可以通过 Dio 包轻松实现。

https://pub.dartlang.org/packages/dio

更新

基于新的 Dio API：

var dio = Dio();
dio.interceptors.add(InterceptorsWrapper(onRequest: (RequestOptions options) async 
  var customHeaders = 
    'content-type': 'application/json'
    // other headers
  ;
  options.headers.addAll(customHeaders);
  return options;
));

Response response = await dio.get("url");
print(response.data.toString());

请参阅documentation 了解更多详情。

【讨论】：

中途拦截我真的很喜欢这个解决方案，它是最简单的方法

这个 dio 对象会在我的所有小部件之间共享吗？如果没有，这个设置只会影响这个 dio 对象。

这个包有一个破坏性错误，如果服务器抛出一个>= 400，就会抛出一个无法捕获的异常。

【参考方案2】：

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

class MyClient extends http.BaseClient
  http.Client _httpClient = new http.Client();

  MyClient(Map defaultHeaders);

  @override
  Future<http.StreamedResponse> send(http.BaseRequest request) 
    request.headers.addAll(defaultHeaders);
    return _httpClient.send(request);
  

【讨论】：

您不需要实例化另一个 Http 客户端。返回request.send() 也可以:)

@GuilhermeV。如果这样做，您将在每个请求上创建一个新的 http 客户端，而不是重新使用现有的客户端，这可能是一个持久连接。

【参考方案3】：

注册自定义HttpClientFactory

Dart 允许注册工厂以创建 HttpClient

class MyHttpOverrides extends HttpOverrides 
  @override
  HttpClient createHttpClient(SecurityContext context) 
    return new MyHttpClient(super.createHttpClient(context));
  


void main() 
  HttpOverrides.global = new MyHttpOverrides();
  runApp(MyApp());

实现自定义HttpClient

实现这样的自定义HttpClient 似乎过于复杂，但也许有更好的方法。

该类从dart:io 及其所有抽象类实现HttpClient。

方法get(...) 和getUrl(...) 被自定义为使用_updateHeaders(...) 添加自定义标头。您需要将其扩展到所有其他方法，例如 head、headUrl、open、post、...

import 'dart:io';

class MyHttpClient implements HttpClient 
  HttpClient _realClient;

  MyHttpClient(this._realClient);

  @override
  bool get autoUncompress => _realClient.autoUncompress;

  @override
  set autoUncompress(bool value) => _realClient.autoUncompress = value;

  @override
  Duration get connectionTimeout => _realClient.connectionTimeout;

  @override
  set connectionTimeout(Duration value) =>
      _realClient.connectionTimeout = value;

  @override
  Duration get idleTimeout => _realClient.idleTimeout;

  @override
  set idleTimeout(Duration value) => _realClient.idleTimeout = value;

  @override
  int get maxConnectionsPerHost => _realClient.maxConnectionsPerHost;

  @override
  set maxConnectionsPerHost(int value) =>
      _realClient.maxConnectionsPerHost = value;

  @override
  String get userAgent => _realClient.userAgent;

  @override
  set userAgent(String value) => _realClient.userAgent = value;

  @override
  void addCredentials(
          Uri url, String realm, HttpClientCredentials credentials) =>
      _realClient.addCredentials(url, realm, credentials);

  @override
  void addProxyCredentials(String host, int port, String realm,
          HttpClientCredentials credentials) =>
      _realClient.addProxyCredentials(host, port, realm, credentials);

  @override
  void set authenticate(
          Future<bool> Function(Uri url, String scheme, String realm) f) =>
      _realClient.authenticate = f;

  @override
  void set authenticateProxy(
          Future<bool> Function(
                  String host, int port, String scheme, String realm)
              f) =>
      _realClient.authenticateProxy = f;

  @override
  void set badCertificateCallback(
          bool Function(X509Certificate cert, String host, int port)
              callback) =>
      _realClient.badCertificateCallback = callback;

  @override
  void close(bool force = false) => _realClient.close(force: force);

  @override
  Future<HttpClientRequest> delete(String host, int port, String path) =>
      _realClient.delete(host, port, path);

  @override
  Future<HttpClientRequest> deleteUrl(Uri url) => _realClient.deleteUrl(url);

  @override
  void set findProxy(String Function(Uri url) f) => _realClient.findProxy = f;

  @override
  Future<HttpClientRequest> get(String host, int port, String path) =>
      _updateHeaders(_realClient.get(host, port, path));

  Future<HttpClientRequest> _updateHeaders(
      Future<HttpClientRequest> httpClientRequest) async 
    return (await httpClientRequest)..headers.add('foo', 'bar');
  

  @override
  Future<HttpClientRequest> getUrl(Uri url) =>
      _updateHeaders(_realClient.getUrl(url.replace(path: url.path)));

  @override
  Future<HttpClientRequest> head(String host, int port, String path) =>
      _realClient.head(host, port, path);

  @override
  Future<HttpClientRequest> headUrl(Uri url) => _realClient.headUrl(url);

  @override
  Future<HttpClientRequest> open(
          String method, String host, int port, String path) =>
      _realClient.open(method, host, port, path);

  @override
  Future<HttpClientRequest> openUrl(String method, Uri url) =>
      _realClient.openUrl(method, url);

  @override
  Future<HttpClientRequest> patch(String host, int port, String path) =>
      _realClient.patch(host, port, path);

  @override
  Future<HttpClientRequest> patchUrl(Uri url) => _realClient.patchUrl(url);

  @override
  Future<HttpClientRequest> post(String host, int port, String path) =>
      _realClient.post(host, port, path);

  @override
  Future<HttpClientRequest> postUrl(Uri url) => _realClient.postUrl(url);

  @override
  Future<HttpClientRequest> put(String host, int port, String path) =>
      _realClient.put(host, port, path);

  @override
  Future<HttpClientRequest> putUrl(Uri url) => _realClient.putUrl(url);

【讨论】：

我发现它很有用，但我仍然觉得有点过于复杂

我也这么认为。

【参考方案4】：

这种简单易行的方法对我有用

var _dio = Dio();
_dio.options.headers= "Authorization" : token;

【参考方案5】：

只是扩展了自定义Client 的@Radek Manasek 想法，我将覆盖所有方法，因此您不必再次编写它们。

import 'dart:convert';

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

class MyClient extends http.BaseClient 
  final Map<String, String> _defaultHeaders;
  http.Client _httpClient = http.Client();

  MyClient(this._defaultHeaders);

  @override
  Future<http.StreamedResponse> send(http.BaseRequest request) 
    return _httpClient.send(request);
  

  @override
  Future<Response> get(url, Map<String, String> headers) 
    return _httpClient.get(url, headers: _mergedHeaders(headers));
  

  @override
  Future<Response> post(url, Map<String, String> headers, dynamic body, Encoding encoding) 
    return _httpClient.post(url, headers: _mergedHeaders(headers), body: body, encoding: encoding);
  

  @override
  Future<Response> patch(url, Map<String, String> headers, dynamic body, Encoding encoding) 
    return _httpClient.patch(url, headers: _mergedHeaders(headers), body: body, encoding: encoding);
  

  @override
  Future<Response> put(url, Map<String, String> headers, dynamic body, Encoding encoding) 
    return _httpClient.put(url, headers: _mergedHeaders(headers), body: body, encoding: encoding);
  

  @override
  Future<Response> head(url, Map<String, String> headers) 
    return _httpClient.head(url, headers: _mergedHeaders(headers));
  

  @override
  Future<Response> delete(url, Map<String, String> headers) 
    return _httpClient.delete(url, headers: _mergedHeaders(headers));
  

  Map<String, String> _mergedHeaders(Map<String, String> headers) =>
      ...?_defaultHeaders, ...?headers;

【讨论】：

这如何与全局 HTTP 覆盖一起工作？ HttpOverrides.createHttpClient 需要返回一个 HttpClient 而不是 BaseClient。