使用 RAD 服务器更改查询数据库时出现 EMS 错误

问题描述

我一直在使用 RAD 服务器作为我们组织的时钟应用程序。从昨天早上 7:00 左右开始，对其中一家公司的 API 调用开始失败，并显示以下错误消息：

First chance exception at $00007FFAB7A24ED9. Exception class EHTTPProtocolException with message 'HTTP/1.1 500 Internal Server Error'. Process TGCTimeClock.exe (21552)
First chance exception at $00007FFAB7A24ED9. Exception class TCustomrESTResponse.EJSONValueError with message 'Response content is not valid JSON'. Process TGCTimeClock.exe (21552)
First chance exception at $00007FFAB7A24ED9. Exception class EEMSClientHTTPError with message 'EMS Error: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-str'. Process TGCTimeClock.exe (21552)

由于我为 2 个独立的公司运行 Time Clock 应用程序，因此我将数据库名称传递给我的端点以访问正确的数据。客户端调用如下：

      dmTimeClockClient.FDMTEmployee.Close;
      dmTimeClockClient.EMSFDClientEmployee.GetEndpoint.Params.Clear;
      dmTimeClockClient.EMSFDClientEmployee.Resource := 'TimeClock/GetEmployees';
      dmTimeClockClient.EMSFDClientEmployee.GetEndpoint.AddParameter('DEPARTMENT_ID',IntToStr(DepartmentID));
      dmTimeClockClient.EMSFDClientEmployee.GetEndpoint.AddParameter('Database',dbname);
      dmTimeClockClient.EMSFDClientEmployee.GetData;

      dmTimeClockClient.FDMTCostCenters.Close;
      dmTimeClockClient.EMSFDClientCostCenters.GetEndpoint.Params.Clear;
      dmTimeClockClient.EMSFDClientCostCenters.Resource := 'TimeClock/GetCostCenters';
      dmTimeClockClient.EMSFDClientCostCenters.GetEndpoint.AddParameter('DEPARTMENT_ID',IntToStr(DepartmentID));
      dmTimeClockClient.EMSFDClientCostCenters.GetEndpoint.AddParameter('Database',dbname);
      dmTimeClockClient.EMSFDClientCostCenters.GetData;

服务器端程序和查询非常简单：

procedure TdmTimeClock.GetCostCenters(const AContext: TEndpointContext; const ARequest: TEndpointRequest; const AResponse: TEndpointResponse);
var ms: TMemoryStream;
begin
  ms := TMemoryStream.Create;

  qryCostCenters.Close;
  qryCostCenters.ParamByName('DEPARTMENT_ID').Value := StrToInt(ARequest.Params.Values['DEPARTMENT_ID']);
  dbname := ARequest.Params.Values['Database'];
  qryCostCenters.Open;

  FDSACostCenters.SavetoStream(ms,TFDStorageFormat.sfJSON);

// Response owns stream
  AResponse.Body.SetStream(ms,'application/vnd.embarcadero.firedac+json',True);
end;

procedure TdmTimeClock.GetEmployees(const AContext: TEndpointContext; const ARequest: TEndpointRequest; const AResponse: TEndpointResponse);
var ms: TMemoryStream;
begin
  ms := TMemoryStream.Create;

  qryEmpInfo.Close;
  qryEmpInfo.ParamByName('DEPARTMENT_ID').Value := StrToInt(ARequest.Params.Values['DEPARTMENT_ID']);
  dbname := ARequest.Params.Values['Database'];
  qryEmpInfo.Open;

  FDSAEmpInfo.SavetoStream(ms,True);
end;

在查询的 before open 事件中，我使用 INI 文件设置数据库参数，如下所示：

procedure TdmTimeClock.qryBeforeOpen(DataSet: TDataSet);
begin
  SetConnectionStr(FDConnectionSTIKS);
end;

procedure SetConnectionStr(var FDConnectionSTIKS: TFDConnection);
var ConfigIni: tinifile;
    DBServerName,Path: string;
begin
  Path := GetCurrentDir;
  ConfigIni := tiniFile.Create(System.IoUtils.TPath.Combine(Path,'Config.ini'));
  DBServerName := ConfigIni.ReadString(AppNode,'ServerName','ZEUS');

  with FDConnectionSTIKS.Params as TFDPhysMSsqlConnectionDefParams do
  begin
    DriverID := 'MSsql';
    Server := DBServerName;
    Database := dbname;
    UserName := DBUserID;
    Password := DBPassword;
  end;

  ConfigIni.Free;
end;

我在谷歌上搜索了错误消息，看起来 DOCTYPE 信息在某种程度上被截断了，因为我发现了以下 DOCTYPE 示例

DOCTYPE html PUBLIC "-I /W3C/ /DTD XHTML 1.0 Strict! /EN". "http://w.t.~.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"

“ict.dtd”在错误消息中被截断。

我找不到定义此 DOCTYPE 的任何地方，或者为什么它与一个数据库不同。被访问的表是相同的。我还有 2 个其他“测试”数据库可以正常工作。这从昨天早上开始发生，但 bpl 或应用程序没有变化。不过，当时我们的 IIS 服务器上似乎发生了 Windows 更新。

另一件奇怪的事情是第一次调用'GetEmployees' 成功，但第二次调用GetCostCenters 失败。如果我注释掉对 GetEmployees 的调用，对 GetCostCenters 的调用以及随后的类似调用仍然会失败。

IIS 日志文件包含以下条目：

2021-07-20 14:09:24 192.168.1.162 GET /RADServer/EMSServer.dll/Security/Login Database=TR_WESTEK&USERNAME=lenm&PASSWORD=******** 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 31
2021-07-20 14:10:04 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetEmployees DEPARTMENT_ID=1&Database=TR_WESTEK 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 46
2021-07-20 14:10:08 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetCostCenters DEPARTMENT_ID=1&Database=TR_WESTEK 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 500 0 0 93

对测试数据库的成功调用会生成以下日志条目：

2021-07-20 14:04:10 192.168.1.162 GET /RADServer/EMSServer.dll/Security/Login Database=WESTEK_TEST&USERNAME=lenm&PASSWORD=******** 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 15
2021-07-20 14:04:20 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetEmployees DEPARTMENT_ID=1&Database=WESTEK_TEST 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 125
2021-07-20 14:04:35 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetCostCenters DEPARTMENT_ID=1&Database=WESTEK_TEST 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 46
2021-07-20 14:04:38 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetShifts Database=WESTEK_TEST 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 62
2021-07-20 14:04:38 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetPayGroups Database=WESTEK_TEST 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 62
2021-07-20 14:04:38 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetPayPeriods Database=WESTEK_TEST&TaxYear=2020&PayGroupID=0 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 46
2021-07-20 14:04:38 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetAbsenteeCodes Database=WESTEK_TEST 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 46
2021-07-20 14:04:38 192.168.1.162 GET /RADServer/EMSServer.dll/TimeClock/GetTimeClock DEPARTMENT_ID=1&START_DATE=07%2F20%2F2021&END_DATE=07%2F20%2F2021&Database=WESTEK_TEST 80 - 216.123.235.214 Embarcadero+RESTClient/1.0 - 200 0 0 62

以下是我使用的 try/except 块：

    try
      dmTimeClockClient.FDMTEmployee.Close;
      dmTimeClockClient.EMSFDClientEmployee.GetEndpoint.Params.Clear;
      dmTimeClockClient.EMSFDClientEmployee.Resource := 'TimeClock/GetEmployees';
      dmTimeClockClient.EMSFDClientEmployee.GetEndpoint.AddParameter('DEPARTMENT_ID',dbname);
      dmTimeClockClient.EMSFDClientCostCenters.GetData;

      dmTimeClockClient.FDMTShifts.Close;
      dmTimeClockClient.EMSFDClientShifts.GetEndpoint.Params.Clear;
      dmTimeClockClient.EMSFDClientShifts.Resource := 'TimeClock/GetShifts';
      dmTimeClockClient.EMSFDClientShifts.GetEndpoint.AddParameter('Database',dbname);
      dmTimeClockClient.EMSFDClientShifts.GetData;

      dmTimeClockClient.FDMTPayGroups.Close;
      dmTimeClockClient.EMSFDClientPayGroups.GetEndpoint.Params.Clear;
      dmTimeClockClient.EMSFDClientPayGroups.Resource := 'TimeClock/GetPayGroups';
      dmTimeClockClient.EMSFDClientPayGroups.GetEndpoint.AddParameter('Database',dbname);
      dmTimeClockClient.EMSFDClientPayGroups.GetData;

      cbPayGroup.ItemIndex := 0;

      dmTimeClockClient.FDMTPayPeriods.Close;
      dmTimeClockClient.EMSFDClientPayPeriods.GetEndpoint.Params.Clear;
      dmTimeClockClient.EMSFDClientPayPeriods.Resource := 'TimeClock/GetPayPeriods';
      dmTimeClockClient.EMSFDClientPayPeriods.GetEndpoint.AddParameter('Database',dbname);
      dmTimeClockClient.EMSFDClientPayPeriods.GetEndpoint.AddParameter('TaxYear',cbTaxYear.ListBox.ListItems[cbTaxYear.ItemIndex].Text);
      dmTimeClockClient.EMSFDClientPayPeriods.GetEndpoint.AddParameter('PayGroupID',IntToStr(cbPayGroup.ListBox.ListItems[cbPayGroup.ItemIndex].Tag));
      dmTimeClockClient.EMSFDClientPayPeriods.GetData;

      dmTimeClockClient.FDMTAbsenteeCodes.Close;
      dmTimeClockClient.EMSFDClientAbsenteeCodes.GetEndpoint.Params.Clear;
      dmTimeClockClient.EMSFDClientAbsenteeCodes.Resource := 'TimeClock/GetAbsenteeCodes';
      dmTimeClockClient.EMSFDClientAbsenteeCodes.GetEndpoint.AddParameter('Database',dbname);
      dmTimeClockClient.EMSFDClientAbsenteeCodes.GetData;
    except
      on E: Exception do
      begin
        TThread.Synchronize(nil,procedure
          begin
            ShowMessageDlg('An Error Occured: ' + E.Message,ditinformation,MsgType);
          end);
      end;
    end;