Question

我有一个.net项目，它与后端java服务器（REST）进行通信，以进行所有相关的业务操作。我正在使用HttpClient发送我的请求。我的问题在于：如果请求失败，即从.Result引发了AggregateException，并且＆＃39;任务被取消了＆＃39;在几乎所有其他对服务器的调用中，我的HttpClient实例丢失了Accept和Accept-Language DefaultRequestHeaders。我在实例化客户端的方式上尝试了许多不同的变体，无论是作为静态类还是通过webconfig，但它在所有情况下都会发生，我没有任何想法。请参阅下面的代码。我从我的web.Config加载属性，这是我的对象，它被正确填写（从here得到）：

public sealed class AthenaHttpClients : ConfigurationSection
{
    private HttpClient _client { get; set; }
    [ConfigurationProperty("athenaFactoryClient", IsRequired = true)]
    public AthenaFactoryHttpClient FactoryClient
    {
        get { return (AthenaFactoryHttpClient)base["athenaFactoryClient"]; }
        set { base["athenaFactoryClient"] = value; }
    }

    private static AthenaHttpClients instance = null;

    public static HttpClient GetClient()
    {
        if (instance == null)
        {
            instance = (AthenaHttpClients)WebConfigurationManager.GetSection("athenaHttpClients");
        }

        instance.FactoryClient.Client = HttpClientFactory.Create(new CustomDelegatingHandlerTokenRefresher());
        instance.FactoryClient.Client.BaseAddress = new Uri(ConfigurationManager.AppSettings["uri"]);
        instance.FactoryClient.Client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(instance.FactoryClient.HeaderValue));
        instance.FactoryClient.Client.DefaultRequestHeaders.AcceptLanguage.Add(new StringWithQualityHeaderValue(instance.FactoryClient.Language));
        instance.FactoryClient.Client.DefaultRequestHeaders.Remove("Authorization");

        return instance.FactoryClient.Client;
    }
}
public class AthenaFactoryHttpClient : ConfigurationElement
{
    [ConfigurationProperty("headerValue", IsRequired = true)]
    public string HeaderValue
    {
        get { return (string)base["headerValue"]; }
        set { base["headerValue"] = value; }
    }

    [ConfigurationProperty("language", IsRequired = true)]
    public string Language
    {
        get { return (string)base["language"]; }
        set { base["language"] = value; }
    }
    public HttpClient Client { get; set; }
}

}

我这样打电话给我的客户：

private HttpClient client = AthenaHttpClients.GetClient();

这是我对后端服务器的一次调用：

internal HttpResponseMessage getStudyContract(string id)
    {
        try
        {
            client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", (string)HttpContext.Current.Session["accessToken"]);
            HttpResponseMessage response = client.GetAsync(restEndpoint + restStudyContractsEndpoint + "/" + id).Result;
            return response;
        }
        catch (AggregateException ex)
        {
            throw new RestHttpClientRequestException(restRequestExceptionMessage, ex.StackTrace);
        }
        catch (Exception ex)
        {
            throw new RestHttpClientRequestException(ex.Message, ex.StackTrace);
        }
    }

（我知道它不是使用带有.Result的异步方法的最佳实现，但现在可以了）。我通过发送带有空字符串的Id强制我的请求getStudyContract（）失败。然后我得到AggregateException，然后对我的客户端的所有后续调用都会丢失Accept和Accept-Language。我不知道自己做错了什么。如果有人有任何建议，请帮忙！

异常后，HttpClient丢失DefaultRequestHeaders

0 个答案: