调用WebService时task.Wait抛出异常，请求技术排查协助

• 调试该问题已超一天，项目即将进入代码冻结阶段，急需解决
• 调用WebService时，在task.Wait()处抛出异常，未修改过代码但此前运行正常
• 代码要么在BillingSummaryAPIPortTypeClient()实例化时失败，要么在task.Wait()处失败
• 底层连接已关闭：接收时发生意外错误，InnerException提示：

接收.....的HTTP响应时出错。这可能是由于服务端点绑定未使用HTTP协议，也可能是服务器中止了HTTP请求上下文（可能因服务关闭）。请查看服务器日志获取详细信息。

• StackTrace：

at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait()
   at BillingServiceAPICall.Program.CallPolServiceForData() in C:\VSCollection\POS\Rel_2022_11\Source\BillingServiceAPICall\Program.cs:line 79 

<startup>
     <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
  </startup>
  <entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
  <parameters>
    <parameter value="mssqllocaldb" />
  </parameters>
</defaultConnectionFactory>
<providers>
  <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
<system.serviceModel>
  <bindings>
    <basicHttpBinding>
      <binding name="BillingSummaryAPISoap11Binding">
        <security mode="Transport" />
      </binding>
      <!--<binding name="BillingSummaryAPISoap11Binding1" />-->
    </basicHttpBinding>
    <customBinding>
       <binding name="BillingSummaryAPISoap12Binding">
         <textMessageEncoding messageVersion="Soap12" />
         <httpsTransport />
       </binding>
    </customBinding>
    <wsHttpBinding>
      <binding name="WSHttpBinding_IEmailService" messageEncoding="Mtom">
        <security mode="Transport" />
      </binding>
    </wsHttpBinding>
    </bindings>
    <client>
     <endpoint address="https://vldv/EmailService.svc"
      binding="wsHttpBinding" bindingConfiguration="WSHttpBinding_IEmailService"
      contract="EmailService.IEmailService" name="WSHttpBinding_IEmailService" />
     <endpoint address="https://vldev3.ww.com/bc/ws/gw/webservice/BillingSummaryAPI"
      binding="customBinding" bindingConfiguration="BillingSummaryAPISoap12Binding"
      contract="BillingService.BillingSummaryAPIPortType" name="BillingSummaryAPISoap12Port"/>
    </client>
  </system.serviceModel>

public static Dictionary<string, double> CallPolServiceForData()
{
    Dictionary<Int32, BResponse> pCallResponse = new Dictionary<int, BResponse>();
    Dictionary<Int32, DateTime> pcCallResponseTime = new Dictionary<int, DateTime>();
    Dictionary<string, double> pcCallResponseTimeDetails = new Dictionary<string, double>();
    List<int?> cancelledPolicies = GetCancelledPoliciesData();
    if (cancelledPolicies != null)
    {
        foreach (var item in cancelledPolicies)
        {
            if (item != null)
            {
                int policyNumber = Convert.ToInt32(item);
                string consoleInfo = policyNumber.ToString(); // to print on console

                pCallResponse.Add(policyNumber, null);

                BillingSummaryAPIPortTypeClient client = new BillingSummaryAPIPortTypeClient();
                authentication auth = new authentication();
                gw_locale l = new gw_locale();
                l.Value = "en_US";
                auth.username = ConfigurationManager.AppSettings["User"];
                auth.password = ConfigurationManager.AppSettings["Pass"];
                PolicyInfo info = new PolicyInfo();
                info.PolicyNumber = policyNumber.ToString();
                try
                {
                    pcCallResponseTime.Add(policyNumber, DateTime.Now);
                    var task = GetResponse(client, auth, l, info);

                    task.Wait();
                    var response = task.Result.@return;
                    pcCallResponseTimeDetails[response.PolicyNumber] = DateTime.
                        Now.Subtract(pcCallResponseTime[policyNumber]).TotalSeconds;
                    pCallResponse[policyNumber] = new BResponse()
                    {
                        OutStandingAmount = response.OutstandingAmount,
                        CancellationDate = response.CancellationDate,
                        ExpirationDate=response.ExpirationDate,
                    };
                    consoleInfo = consoleInfo + " Success";
                    Console.WriteLine(consoleInfo);

                }
                catch (Exception ex)
                {
                    pcCallResponseTimeDetails[policyNumber.ToString()] = DateTime.
                        Now.Subtract(pcCallResponseTime[policyNumber]).TotalSeconds;
                    pCallResponse[policyNumber] = new BResponse()
                    {
                        ErrorDesc = (ex.InnerException != null) ?
                            ex.InnerException.Message : ex.ToString()
                    };
                    consoleInfo = consoleInfo + " Error - " + pCallResponse[policyNumber].ErrorDesc;
                    Console.WriteLine(consoleInfo);
                }
            }
        }
        SaveResultToStg(pCallResponse);
    }
    return pcCallResponseTimeDetails;
}

基础连通性排查 #

• 直接访问服务地址https://vldev3.ww.com/bc/ws/gw/webservice/BillingSummaryAPI，确认服务是否正常响应（比如返回WSDL页面）
• 检查网络环境：是否有代理变更、防火墙规则调整，导致客户端无法访问服务端；测试同一网络下其他机器能否正常调用该服务
• 验证服务端状态：联系运维确认服务是否正常运行，是否有重启、部署或配置变更，查看服务端日志是否有报错记录

绑定与配置问题排查 #

• 检查SSL/TLS版本兼容性：.NET 4.5.2默认可能不支持TLS 1.2，而服务端可能已禁用旧版本TLS。在客户端代码开头添加强制TLS 1.2的代码：

System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;

• 检查自定义绑定配置：确认BillingSummaryAPISoap12Binding的httpsTransport是否需要额外配置（比如最大消息大小、超时时间），尝试增加超时时间避免连接被提前关闭：

<httpsTransport maxReceivedMessageSize="2147483647" maxBufferSize="2147483647" timeout="00:10:00" />

• 验证客户端端点配置：确认服务地址、绑定类型、契约名称是否与服务端最新配置一致，尝试重新生成服务引用（Update Service Reference）

代码层面优化 #

• 避免同步阻塞异步方法：task.Wait()容易导致死锁或上下文问题，建议将方法改为异步模式，使用await替代Wait()：

public static async Task<Dictionary<string, double>> CallPolServiceForData()
{
    // ... 原有代码
    var response = (await GetResponse(client, auth, l, info)).@return;
    // ... 原有代码
}

• 客户端实例管理：在循环中每次创建新的BillingSummaryAPIPortTypeClient可能导致连接耗尽，建议复用客户端实例或使用using确保资源释放：

using (BillingSummaryAPIPortTypeClient client = new BillingSummaryAPIPortTypeClient())
{
    // ... 调用服务代码
}

• 增加详细日志：在调用前后记录请求参数、时间戳，捕获更底层的网络异常（比如WebException），以便定位具体错误原因

证书与安全问题排查 #

• 检查服务端SSL证书是否过期或不被客户端信任：若服务端使用自签名证书，需将证书导入客户端的信任根证书存储
• 验证身份认证信息：确认ConfigurationManager.AppSettings["User"]和Pass的取值是否正确，是否有密码过期、权限变更的情况

内容的提问来源于stack exchange，提问作者Ditty