HttpClient问题

  • HttPClient使用完之后不会立即关闭开启网络连接时会占用底层socket资源，但在HttpClient调用其本身的Dispose方法时，并不能立刻释放该资源

  • 如果频繁的使用HttpClient,频繁的打开链接，关闭链接消耗就会很大

    HttpClientFactory

  • 在.NET Core 2.1版本之后引入的 HttpClientFactory解决了HttpClient的所有痛点。有了 HttpClientFactory，我们不需要关心如何创建HttpClient，又如何释放它。通过它可以创建具有特定业务的HttpClient，而且可以很友好的和 DI 容器结合使用，更为灵活。

  • HttpClientFactory 创建的HttpClient，也即是HttpClientHandler，只是这些个HttpClient被放到了“池子”中，工厂每次在create的时候会自动判断是新建还是复用。(默认生命周期为2min，默认的生命周期可以修改）

    服务配置

    新建一个类 用作service配置

    1. /// <summary>
    2. /// 初始化HttpClient配置
    3. /// </summary>
    4. /// <param name="services"></param>
    5. public static void AddHttpClientSevice(this IServiceCollection services)
    6. {
    7.    if (services == null) throw new ArgumentNullException(nameof(services));
    8.    //添加默认服务 没有指定服务名称的都可以使用默认服务
    9.    services.AddHttpClient();//可以添加多个
    10.    //获取自定义配置 每一个需要连接的对象都已使用指定名称的服务，所以服务需要命名
    11.    var clientconfig = AppsettingConfig.HttpClientConfig;//我在appseeting中配置了是一个数组
    12.    if (clientconfig?.Count > 0)
    13.    {
    14.        foreach (var item in clientconfig)
    15.        {
    16.            if (string.IsNullOrWhiteSpace(item.ServiceName)) continue;//检测服务名称
    17.            services.AddHttpClient(item.ServiceName, client =>
    18.            {
    19.                client.BaseAddress = new Uri(item.BaseAddress);
    20.                if (item.Timeout > 0)
    21.                    client.Timeout = TimeSpan.FromSeconds(item.Timeout);//设置超时
    22.                if (item.DeafaultRequestHeader?.Count > 0)//添加默认header
    23.                    foreach (var header in item.DeafaultRequestHeader)
    24.                    {
    25.                        client.DefaultRequestHeaders.Add(header.Key, header.Value);//可以设置都有的Header 不能添加“Content-Type”
    26.                    }
    28.            }).ConfigurePrimaryHttpMessageHandler(() =>
    29.            {
    30.                //配置代理 如果配有代理
    31.                if (!item.Proxy.IsActive) return new HttpClientHandler(); 
    32.                var hander = new HttpClientHandler()
    33.                {
    34.                    AllowAutoRedirect = false,
    35.                    UseDefaultCredentials = true,
    37.                };
    38.                hander.Proxy = new WebProxy(item.Proxy.Host, item.Proxy.Port);//代理地址
    39.                hander.Proxy.Credentials = new NetworkCredential(item.Proxy.UserName, item.Proxy.PassWord, item.Proxy.Domain);//账号。密码。域
    40.                return hander;
    41.            });
    42.        }
    43.    }
    44. }
    45. //注册封装类
    46.           services.AddSingleton<IHttpHelper, HttpHelper>();
    47.   }

    StartUp中添加服务

    //注册http请求服务
services.AddHttpClientSevice();

    封装HttpHelper

    接口声明

    public interface IHttpHelper
  {
      /// <summary>
      /// Get请求
      /// </summary>
      /// <param name="url">完整的Url</param>
      /// <param name="headers">自定义header</param>
      /// <param name="servicename">服务名称</param>
      /// <returns></returns>
      public Task<HttpResponseMessage> GetAsync(string url, Dictionary<string, string> headers = null, string servicename = "");
      /// <summary>
      /// Post请求
      /// </summary>
      /// <param name="url">完整的Url</param>
      /// <param name="body">body体</param>
      /// <param name="headers">头</param>
      /// <param name="servicename">servicename</param>
      /// <returns></returns>
      public Task<HttpResponseMessage> PostAsync(string url, string body = "", Dictionary<string, string> headers = null, string servicename = "");

  }

    接口实现

    public class HttpHelper : IHttpHelper
  {
      private readonly IHttpClientFactory _httpClientFactory;
      private readonly ILogHelper _logHelper;

      public HttpHelper(IHttpClientFactory httpClientFactory, ILogHelper logHelper)
      {
          _httpClientFactory = httpClientFactory;
          _logHelper = logHelper;
      }

      /// <summary>
      /// Get请求
      /// </summary>
      /// <param name="url">完整的Url</param>
      /// <param name="headers">自定义header</param>
      /// <param name="servicename">服务名称</param>
      /// <returns></returns>
      public Task<HttpResponseMessage> GetAsync(string url, Dictionary<string, string> headers = null, string servicename = "")
      {
          try
          {
              HttpClient client;
              if (string.IsNullOrWhiteSpace(servicename))
              {
                  client = _httpClientFactory.CreateClient();
              }
              else
              {
                  client = _httpClientFactory.CreateClient(servicename);
              }
              if (headers?.Count > 0)
              {
                  foreach (var item in headers)
                  {
                      client.DefaultRequestHeaders.Add(item.Key, item.Value);
                  }
              }

              return client.GetAsync(url);
          }
          catch (Exception ex)
          {
              _logHelper.LogErr("HttpHelper.GetAsync", ex);
              throw ex;
          }
      }
      /// <summary>
      /// Post请求
      /// </summary>
      /// <param name="url">完整的Url</param>
      /// <param name="body">body体</param>
      /// <param name="headers">头</param>
      /// <param name="servicename">servicename</param>
      /// <returns></returns>
      public Task<HttpResponseMessage> PostAsync(string url, string body = "", Dictionary<string, string> headers = null, string servicename = "")
      {
          try
          {
              HttpClient client;
              if (string.IsNullOrWhiteSpace(servicename))
              {
                  client = _httpClientFactory.CreateClient();
              }
              else
              {
                  client = _httpClientFactory.CreateClient(servicename);
              }
              if (headers?.Count > 0)
              {
                  foreach (var item in headers)
                  {
                      client.DefaultRequestHeaders.Add(item.Key, item.Value);
                  }
              }
              var content = new StringContent(body, Encoding.UTF8, "application/json");
              return client.PostAsync(url, content);
          }
          catch (Exception ex)
          {
              _logHelper.LogErr("HttpHelper.PostAsync", ex);
              throw ex;
          }
      }

  }

    最后直接用就好 可以对返回的HttpResponseMessage进行操作，比如判断StatusCode 读取返回值 Content.ReadAsStringAsync()