Question

我有一个HttpClient，我用它来使用REST API。但是，我在设置Authorization标头时遇到问题。我需要将标头设置为我从执行OAuth请求时收到的令牌。我看到了.NET的一些代码，建议如下，

httpClient.DefaultRequestHeaders.Authorization = new Credential(OAuth.token);

然而，Credential类在WinRT中不存在。任何人都有任何想法如何设置授权标题？

Answer 1

所以这样做的方法如下，

httpClient.DefaultRequestHeaders.Authorization =
    new AuthenticationHeaderValue("Bearer", "Your Oauth token");

Answer 2

request.DefaultRequestHeaders.Authorization = 
    new AuthenticationHeaderValue(
        "Basic", Convert.ToBase64String(
            System.Text.ASCIIEncoding.ASCII.GetBytes(
               $"{yourusername}:{yourpwd}")));

Answer 3

我寻找一个处理这个问题的好方法，我正在寻找同样的问题。希望这个答案能帮助每个有同样问题的人都喜欢我。

using (var client = new HttpClient())
{
    var url = "https://www.theidentityhub.com/{tenant}/api/identity/v1";
    client.DefaultRequestHeaders.Add("Authorization", "Bearer " + accessToken);
    var response = await client.GetStringAsync(url);
    // Parse JSON response.
    ....
}

来自https://www.theidentityhub.com/hub/Documentation/CallTheIdentityHubApi

的参考资料

Answer 4

我同意TheWhiteRabbit的答案，但是如果你使用HttpClient进行大量调用，我认为代码似乎有点重复。

我认为有两种方法可以改善答案。

创建一个帮助程序类来创建客户端：

public static class ClientHelper
{
    // Basic auth
    public static HttpClient GetClient(string username,string password)
    {
            var authValue = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes($"{username}:{password}")));

            var client = new HttpClient(){
                DefaultRequestHeaders = { Authorization = authValue}
                //Set some other client defaults like timeout / BaseAddress
            };
            return client;
    }

    // Auth with bearer token
    public static HttpClient GetClient(string token)
    {
            var authValue = new AuthenticationHeaderValue("Bearer", token);

            var client = new HttpClient(){
                DefaultRequestHeaders = { Authorization = authValue}
                //Set some other client defaults like timeout / BaseAddress
            };
            return client;
    }
}

<强>用法：

using(var client = ClientHelper.GetClient(username,password))
{
    //Perform some http call
}

using(var client = ClientHelper.GetClient(token))
{
    //Perform some http call
}

创建扩展方法：

没有赢得美容奖，但效果很好：）

    public static class HttpClientExtentions
    {
        public static AuthenticationHeaderValue ToAuthHeaderValue(this string username, string password)
        {
            return new AuthenticationHeaderValue("Basic",
        Convert.ToBase64String(
            System.Text.Encoding.ASCII.GetBytes(
                $"{username}:{password}")));
        }
    }

<强>用法：

using (var client = new HttpClient())
{
    client.DefaultRequestHeaders.Authorization = _username.ToAuthHeaderValue(_password); 
}

我认为上面两个选项使得客户端使用语句的重复性稍差。请记住，如果您正在进行多个http调用，那么重用HttpClient是最佳做法，但我认为这个问题有点超出范围。

Answer 5

因为重用HttpClient实例是良好做法，性能和端口耗尽问题，并且因为没有一个答案提供此解决方案（甚至引导您对于不良行为:(），我在这里提到了我对类似问题所作答案的链接：

https://stackoverflow.com/a/40707446/717372

有关如何充分利用HttpClient的一些消息来源：

https://aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/

https://blogs.msdn.microsoft.com/alazarev/2017/12/29/disposable-finalizers-and-httpclient/

Answer 6

如果要发送带有Bearer令牌的HttpClient请求，此代码可能是一个很好的解决方案：

var requestMessage = new HttpRequestMessage
{
    Method = HttpMethod.Post,
    Content = new StringContent(".....", Encoding.UTF8, "application/json"),
    RequestUri = new Uri(".....")
};

requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Bearer", "Your token");

var response = await _httpClient.SendAsync(requestMessage);

Answer 7

使用C＃HttpClient设置基本身份验证。以下代码对我有用。

   using (var client = new HttpClient())
        {
            var webUrl ="http://localhost/saleapi/api/";
            var uri = "api/sales";
            client.BaseAddress = new Uri(webUrl);
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            client.DefaultRequestHeaders.ConnectionClose = true;

            //Set Basic Auth
            var user = "username";
            var password = "password";
            var base64String =Convert.ToBase64String( Encoding.ASCII.GetBytes($"{user}:{password}"));
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",base64String);

            var result = await client.PostAsJsonAsync(uri, model);
            return result;
        }

Answer 8

我就是这样做的：

using (HttpClient httpClient = new HttpClient())
{
   Dictionary<string, string> tokenDetails = null;
   var messageDetails = new Message { Id = 4, Message1 = des };
   HttpClient client = new HttpClient();
   client.BaseAddress = new Uri("http://localhost:3774/");
   var login = new Dictionary<string, string>
       {
           {"grant_type", "password"},
           {"username", "sa@role.com"},
           {"password", "lopzwsx@23"},
       };
   var response = client.PostAsync("Token", new FormUrlEncodedContent(login)).Result;
   if (response.IsSuccessStatusCode)
   {
      tokenDetails = JsonConvert.DeserializeObject<Dictionary<string, string>>(response.Content.ReadAsStringAsync().Result);
      if (tokenDetails != null && tokenDetails.Any())
      {
         var tokenNo = tokenDetails.FirstOrDefault().Value;
         client.DefaultRequestHeaders.Add("Authorization", "Bearer " + tokenNo);
         client.PostAsJsonAsync("api/menu", messageDetails)
             .ContinueWith((postTask) => postTask.Result.EnsureSuccessStatusCode());
      }
   }
}

这个you-tube视频帮了我很多忙。请检查一下。 https://www.youtube.com/watch?v=qCwnU06NV5Q

Answer 9

我建议你

HttpClient.DefaultRequestHeaders.Add("Authorization", "Bearer <token>");

然后您可以像这样使用它：

 var response = await client.GetAsync(url);
    if (response.IsSuccessStatusCode)
    {
          responseMessage = await response.Content.ReadAsAsync<ResponseMessage>();
    }

Answer 10

使用基本授权和Json参数。

using (HttpClient client = new HttpClient())
                    {
                        var request_json = "your json string";

                        var content = new StringContent(request_json, Encoding.UTF8, "application/json");

                        var authenticationBytes = Encoding.ASCII.GetBytes("YourUsername:YourPassword");

                        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
                               Convert.ToBase64String(authenticationBytes));
                        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                        var result = await client.PostAsync("YourURL", content);

                        var result_string = await result.Content.ReadAsStringAsync();
                    }

Answer 11

我正在设置不记名令牌

httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);

它在一个端点上工作，但在另一个端点上却没有。问题是我在b上使用小写的"bearer"。更改后，它现在适用于我正在使用的两个api。如果您甚至没有将它视为寻找针头的干草堆之一，那么就很容易错过。

请确保使用大写字母"Bearer"。

Answer 12

6年后，但添加此内容以防他人使用。

https://www.codeproject.com/Tips/996401/Authenticate-WebAPIs-with-Basic-and-Windows-Authen

var authenticationBytes = Encoding.ASCII.GetBytes("<username>:<password>");
using (HttpClient confClient = new HttpClient())
{
  confClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", 
         Convert.ToBase64String(authenticationBytes));
  confClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(Constants.MediaType));  
  HttpResponseMessage message = confClient.GetAsync("<service URI>").Result;
  if (message.IsSuccessStatusCode)
  {
    var inter = message.Content.ReadAsStringAsync();
    List<string> result = JsonConvert.DeserializeObject<List<string>>(inter.Result);
  }
}

Answer 13

使用AuthenticationHeaderValue类System.Net.Http汇编

public AuthenticationHeaderValue(
    string scheme,
    string parameter
)

我们可以为Authorization设置或更新现有的httpclient标头，如下所示：

httpclient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", TokenResponse.AccessToken);

Answer 14

BaseWebApi.cs

public abstract class BaseWebApi
{
    //Inject HttpClient from Ninject
    private readonly HttpClient _httpClient;
    public BaseWebApi(HttpClient httpclient)
    {
        _httpClient = httpClient;
    }

    public async Task<TOut> PostAsync<TOut>(string method, object param, Dictionary<string, string> headers, HttpMethod httpMethod)
    {
        //Set url

        HttpResponseMessage response;
        using (var request = new HttpRequestMessage(httpMethod, url))
        {
            AddBody(param, request);
            AddHeaders(request, headers);
            response = await _httpClient.SendAsync(request, cancellationToken);
        }

        if(response.IsSuccessStatusCode)
        {
             return await response.Content.ReadAsAsync<TOut>();
        }
        //Exception handling
    }

    private void AddHeaders(HttpRequestMessage request, Dictionary<string, string> headers)
    {
        request.Headers.Accept.Clear();
        request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        if (headers == null) return;

        foreach (var header in headers)
        {
            request.Headers.Add(header.Key, header.Value);
        }
    }

    private static void AddBody(object param, HttpRequestMessage request)
    {
        if (param != null)
        {
            var content = JsonConvert.SerializeObject(param);
            request.Content = new StringContent(content);
            request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
        }
    }

SubWebApi.cs

public sealed class SubWebApi : BaseWebApi
{
    public SubWebApi(HttpClient httpClient) : base(httpClient) {}

    public async Task<StuffResponse> GetStuffAsync(int cvr)
    {
        var method = "get/stuff";
        var request = new StuffRequest 
        {
            query = "GiveMeStuff"
        }
        return await PostAsync<StuffResponse>(method, request, GetHeaders(), HttpMethod.Post);
    }
    private Dictionary<string, string> GetHeaders()
    {
        var headers = new Dictionary<string, string>();
        var basicAuth = GetBasicAuth();
        headers.Add("Authorization", basicAuth);
        return headers;
    }

    private string GetBasicAuth()
    {
        var byteArray = Encoding.ASCII.GetBytes($"{SystemSettings.Username}:{SystemSettings.Password}");
        var authString = Convert.ToBase64String(byteArray);
        return $"Basic {authString}";
    }
}

Answer 15

UTF8选项

request.DefaultRequestHeaders.Authorization = 
new AuthenticationHeaderValue(
    "Basic", Convert.ToBase64String(
        System.Text.Encoding.UTF8.GetBytes(
           $"{yourusername}:{yourpwd}")));

Answer 16

在net .core中，您可以使用

            var client = new HttpClient();
            client.SetBasicAuthentication(userName, password);

或

            var client = new HttpClient();
            client.SetBearerToken(token);

Answer 17

对于现在（2021 年）发现此旧线程的任何人，请查看关于 HttpClientFactory 的 this documentation，它是可注入的，并且还会在每个请求上重新运行，避免过期令牌，这将使其对承载者有用令牌、生成的客户端、池化等

TL;DR：使用 HttpClientFactory 和 DelegatingHandler 作为中间件处理您配置的客户端的所有传出请求。

这就是我为 Azure Identity（由 Azure 管理）添加不记名者的方式，但您当然可以随心所欲地获取令牌；

using Microsoft.Azure.Services.AppAuthentication;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;

public class BearerTokenHandler : DelegatingHandler
    {
        public BearerTokenHandler(AzureServiceTokenProvider tokenProvider, string resource)
        {
            TokenProvider = tokenProvider;
            Resource = resource;
        }

        public AzureServiceTokenProvider TokenProvider { get; }
        public string Resource { get; }

        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            if (!request.Headers.Contains("Authorization"))
            {
                // Fetch your token here
                string token = await TokenProvider.GetAccessTokenAsync(Resource);
                request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
            }

            return await base.SendAsync(request, cancellationToken);
        }
    }

我在 Startup 中像这样配置我的类型化客户端（用 NSwag 生成）；

   var accessTokenProvider = new AzureServiceTokenProvider("<your-connection-string-for-access-token-provider>");

  builder.Services.AddHttpClient<IOrdersClient, OrdersClient>().ConfigureHttpClient(async conf =>
            {
                conf.BaseAddress = new Uri("<your-api-base-url>");
            }).AddHttpMessageHandler(() => new BearerTokenHandler(accessTokenProvider, "https://your-azure-tenant.onmicrosoft.com/api"));

然后你可以在任何你喜欢的地方注入你的 IOrdersClient，所有的请求都会有承载。

Answer 18

如果您想重用HttpClient，建议不要使用DefaultRequestHeaders，因为它们是随每个请求一起发送的。

您可以尝试以下方法：

var requestMessage = new HttpRequestMessage
    {
        Method = HttpMethod.Post,
        Content = new StringContent("...", Encoding.UTF8, "application/json"),
        RequestUri = new Uri("..."),
    };

requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Basic", 
    Convert.ToBase64String(System.Text.ASCIIEncoding.ASCII.GetBytes($"{user}:{password}")));

Answer 19

使用现有库可能会更容易。

例如，下面的扩展方法是随Identity Server 4添加的 https://www.nuget.org/packages/IdentityModel/

 public static void SetBasicAuthentication(this HttpClient client, string userName, string password);
    //
    // Summary:
    //     Sets a basic authentication header.
    //
    // Parameters:
    //   request:
    //     The HTTP request message.
    //
    //   userName:
    //     Name of the user.
    //
    //   password:
    //     The password.
    public static void SetBasicAuthentication(this HttpRequestMessage request, string userName, string password);
    //
    // Summary:
    //     Sets a basic authentication header for RFC6749 client authentication.
    //
    // Parameters:
    //   client:
    //     The client.
    //
    //   userName:
    //     Name of the user.
    //
    //   password:
    //     The password.
    public static void SetBasicAuthenticationOAuth(this HttpClient client, string userName, string password);
    //
    // Summary:
    //     Sets a basic authentication header for RFC6749 client authentication.
    //
    // Parameters:
    //   request:
    //     The HTTP request message.
    //
    //   userName:
    //     Name of the user.
    //
    //   password:
    //     The password.
    public static void SetBasicAuthenticationOAuth(this HttpRequestMessage request, string userName, string password);
    //
    // Summary:
    //     Sets an authorization header with a bearer token.
    //
    // Parameters:
    //   client:
    //     The client.
    //
    //   token:
    //     The token.
    public static void SetBearerToken(this HttpClient client, string token);
    //
    // Summary:
    //     Sets an authorization header with a bearer token.
    //
    // Parameters:
    //   request:
    //     The HTTP request message.
    //
    //   token:
    //     The token.
    public static void SetBearerToken(this HttpRequestMessage request, string token);
    //
    // Summary:
    //     Sets an authorization header with a given scheme and value.
    //
    // Parameters:
    //   client:
    //     The client.
    //
    //   scheme:
    //     The scheme.
    //
    //   token:
    //     The token.
    public static void SetToken(this HttpClient client, string scheme, string token);
    //
    // Summary:
    //     Sets an authorization header with a given scheme and value.
    //
    // Parameters:
    //   request:
    //     The HTTP request message.
    //
    //   scheme:
    //     The scheme.
    //
    //   token:
    //     The token.
    public static void SetToken(this HttpRequestMessage request, string scheme, string token);

Answer 20

Oauth流程很复杂，总是存在一个或多个错误的余地。我的建议是始终使用样板代码和一组库进行OAuth身份验证流程，这将使您的生活更轻松。

这是一组库的链接。OAuth Libraries for .Net

Answer 21

首先，我不会直接使用 HttpClient。犯错太容易了——尤其是在头球方面。 DefaultHeadersCollection 不是一成不变的，也不是线程安全的，因为应用程序的其他部分可以更改您的标头。最好在拨打电话时设置标题。如果您正在使用抽象，并且建议这样做，因为该区域中的类有点混乱，您可能需要一个标头集合并将它们放在您的 HttpRequestMessage 中，然后再发送它。您需要确保将内容标题放在内容上，而不是消息上。

Code Reference

foreach (var headerName in request.Headers.Names)
{
    //"Content-Type"
    if (string.Compare(headerName, HeadersExtensions.ContentTypeHeaderName, StringComparison.OrdinalIgnoreCase) == 0)
    {
        //Note: not sure why this is necessary...
        //The HttpClient class seems to differentiate between content headers and request message headers, but this distinction doesn't exist in the real world...
        //TODO: Other Content headers
        httpContent?.Headers.Add(HeadersExtensions.ContentTypeHeaderName, request.Headers[headerName]);
    }
    else
    {
        httpRequestMessage.Headers.Add(headerName, request.Headers[headerName]);
    }
}

这是一个数据结构，您可以使用它来发送包含标头的请求。

Code Reference

public interface IRequest
{
    CancellationToken CancellationToken { get; }
    string? CustomHttpRequestMethod { get; }
    IHeadersCollection Headers { get; }
    HttpRequestMethod HttpRequestMethod { get; }
    AbsoluteUrl Uri { get; }
}

public interface IRequest<TBody> : IRequest
{
    TBody? BodyData { get; }
}

还有一个标题集合：

Code Reference

public sealed class HeadersCollection : IHeadersCollection
{
    #region Fields
    private readonly IDictionary<string, IEnumerable<string>> dictionary;
    #endregion

    #region Public Constructors

    public HeadersCollection(IDictionary<string, IEnumerable<string>> dictionary) => this.dictionary = dictionary;

    public HeadersCollection(string key, string value) : this(ImmutableDictionary.CreateRange(
                new List<KeyValuePair<string, IEnumerable<string>>>
                {
                    new(key, ImmutableList.Create(value))
                }
                ))
    {
    }

    #endregion Public Constructors

    #region Public Properties
    public static HeadersCollection Empty { get; } = new HeadersCollection(ImmutableDictionary.Create<string, IEnumerable<string>>());
    public IEnumerable<string> Names => dictionary.Keys;
    IEnumerable<string> IHeadersCollection.this[string name] => dictionary[name];
    #endregion Public Properties

    #region Public Methods
    public bool Contains(string name) => dictionary.ContainsKey(name);

    public IEnumerator<KeyValuePair<string, IEnumerable<string>>> GetEnumerator() => dictionary.GetEnumerator();

    IEnumerator IEnumerable.GetEnumerator() => dictionary.GetEnumerator();
    public override string ToString() => string.Join("\r\n", dictionary.Select(kvp => $"{kvp.Key}: {string.Join(", ", kvp.Value)}\r\n"));
    #endregion
}

查看所有工作代码和示例 here。

Answer 22

如果您使用 Visual Studio IISExpress 调试模式并连接到 HTTP 端口而不是 HTTPS 端口，您可能会发现身份验证标头被丢弃。

切换到 SLL 连接，它们会再次出现。

不确定原因，可能是设置重定向了 http 流量并导致身份验证被删除。

Answer 23

如果您从服务中接收json或xml，这可能会有效，我认为这可以让您了解标题和T类型的工作原理，如果您使用函数MakeXmlRequest（将结果放入xmldocumnet））和MakeJsonRequest（将json放在你想要的类中，与json响应具有相同的结构）下一步

/*-------------------------example of use-------------*/
MakeXmlRequest<XmlDocument>("your_uri",result=>your_xmlDocument_variable =     result,error=>your_exception_Var = error);

MakeJsonRequest<classwhateveryouwant>("your_uri",result=>your_classwhateveryouwant_variable=result,error=>your_exception_Var=error)
/*-------------------------------------------------------------------------------*/


public class RestService
{
    public void MakeXmlRequest<T>(string uri, Action<XmlDocument> successAction, Action<Exception> errorAction)
    {
        XmlDocument XMLResponse = new XmlDocument();
        string wufooAPIKey = ""; /*or username as well*/
        string password = "";
        StringBuilder url = new StringBuilder();
        url.Append(uri);
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url.ToString());
        string authInfo = wufooAPIKey + ":" + password;
        authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
        request.Timeout = 30000;
        request.KeepAlive = false;
        request.Headers["Authorization"] = "Basic " + authInfo;
        string documento = "";
        MakeRequest(request,response=> documento = response,
                            (error) =>
                            {
                             if (errorAction != null)
                             {
                                errorAction(error);
                             }
                            }
                   );
        XMLResponse.LoadXml(documento);
        successAction(XMLResponse);
    }



    public void MakeJsonRequest<T>(string uri, Action<T> successAction, Action<Exception> errorAction)
    {
        string wufooAPIKey = "";
        string password = "";
        StringBuilder url = new StringBuilder();
        url.Append(uri);
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url.ToString());
        string authInfo = wufooAPIKey + ":" + password;
        authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
        request.Timeout = 30000;
        request.KeepAlive = false;
        request.Headers["Authorization"] = "Basic " + authInfo;
       // request.Accept = "application/json";
      //  request.Method = "GET";
        MakeRequest(
           request,
           (response) =>
           {
               if (successAction != null)
               {
                   T toReturn;
                   try
                   {
                       toReturn = Deserialize<T>(response);
                   }
                   catch (Exception ex)
                   {
                       errorAction(ex);
                       return;
                   }
                   successAction(toReturn);
               }
           },
           (error) =>
           {
               if (errorAction != null)
               {
                   errorAction(error);
               }
           }
        );
    }
    private void MakeRequest(HttpWebRequest request, Action<string> successAction, Action<Exception> errorAction)
    {
        try{
            using (var webResponse = (HttpWebResponse)request.GetResponse())
            {
                using (var reader = new StreamReader(webResponse.GetResponseStream()))
                {
                    var objText = reader.ReadToEnd();
                    successAction(objText);
                }
            }
        }catch(HttpException ex){
            errorAction(ex);
        }
    }
    private T Deserialize<T>(string responseBody)
    {
        try
        {
            var toReturns = JsonConvert.DeserializeObject<T>(responseBody);
             return toReturns;
        }
        catch (Exception ex)
        {
            string errores;
            errores = ex.Message;
        }
        var toReturn = JsonConvert.DeserializeObject<T>(responseBody);
        return toReturn;
    }
}
}

Answer 24

static async Task<AccessToken> GetToken()
{
        string clientId = "XXX";
        string clientSecret = "YYY";
        string credentials = String.Format("{0}:{1}", clientId, clientSecret);

        using (var client = new HttpClient())
        {
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes(credentials)));
            List<KeyValuePair<string, string>> requestData = new List<KeyValuePair<string, string>>();
            requestData.Add(new KeyValuePair<string, string>("grant_type", "client_credentials"));
            FormUrlEncodedContent requestBody = new FormUrlEncodedContent(requestData);
            var request = await client.PostAsync("https://accounts.spotify.com/api/token", requestBody);
            var response = await request.Content.ReadAsStringAsync();
            return JsonConvert.DeserializeObject<AccessToken>(response);
        }
    }

Answer 25

这可能有助于设置标题：

WebClient client = new WebClient();

string authInfo = this.credentials.UserName + ":" + this.credentials.Password;
authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
client.Headers["Authorization"] = "Basic " + authInfo;

设置HttpClient的授权标头

25 个答案:

创建一个帮助程序类来创建客户端：

创建扩展方法：

UTF8选项