Datasnap File Upload

[Captnemo]

Hier ist mein Proxy:

Delphi-Quellcode:

//
// Erzeugt vom DataSnap-Proxy-Generator.
// 11.09.2012 15:05:33
//

unit proxy;

interface

uses Data.DBXCommon, Data.DBXClient, Data.DBXDataSnap, Data.DBXJSON, Datasnap.DSProxy, System.Classes, System.SysUtils, Data.DB, Data.SqlExpr, Data.DBXDBReaders, Data.DBXJSONReflect;

type
  TServerMethods1Client = class(TDSAdminClient)
  private
    FEchoStringCommand: TDBXCommand;
    FReverseStringCommand: TDBXCommand;
    FUploadFileCommand: TDBXCommand;
  public
    constructor Create(ADBXConnection: TDBXConnection); overload;
    constructor Create(ADBXConnection: TDBXConnection; AInstanceOwner: Boolean); overload;
    destructor Destroy; override;
    function EchoString(Value: string): string;
    function ReverseString(Value: string): string;
    procedure UploadFile(str: TStream; Store: string; FileName: string);
  end;

implementation

function TServerMethods1Client.EchoString(Value: string): string;
begin
  if FEchoStringCommand = nil then
  begin
    FEchoStringCommand := FDBXConnection.CreateCommand;
    FEchoStringCommand.CommandType := TDBXCommandTypes.DSServerMethod;
    FEchoStringCommand.Text := 'TServerMethods1.EchoString';
    FEchoStringCommand.Prepare;
  end;
  FEchoStringCommand.Parameters[0].Value.SetWideString(Value);
  FEchoStringCommand.ExecuteUpdate;
  Result := FEchoStringCommand.Parameters[1].Value.GetWideString;
end;

function TServerMethods1Client.ReverseString(Value: string): string;
begin
  if FReverseStringCommand = nil then
  begin
    FReverseStringCommand := FDBXConnection.CreateCommand;
    FReverseStringCommand.CommandType := TDBXCommandTypes.DSServerMethod;
    FReverseStringCommand.Text := 'TServerMethods1.ReverseString';
    FReverseStringCommand.Prepare;
  end;
  FReverseStringCommand.Parameters[0].Value.SetWideString(Value);
  FReverseStringCommand.ExecuteUpdate;
  Result := FReverseStringCommand.Parameters[1].Value.GetWideString;
end;

procedure TServerMethods1Client.UploadFile(str: TStream; Store: string; FileName: string);
begin
  if FUploadFileCommand = nil then
  begin
    FUploadFileCommand := FDBXConnection.CreateCommand;
    FUploadFileCommand.CommandType := TDBXCommandTypes.DSServerMethod;
    FUploadFileCommand.Text := 'TServerMethods1.UploadFile';
    FUploadFileCommand.Prepare;
  end;
  FUploadFileCommand.Parameters[0].Value.SetStream(str, FInstanceOwner);
  FUploadFileCommand.Parameters[1].Value.SetWideString(Store);
  FUploadFileCommand.Parameters[2].Value.SetWideString(FileName);
  FUploadFileCommand.ExecuteUpdate;
end;


constructor TServerMethods1Client.Create(ADBXConnection: TDBXConnection);
begin
  inherited Create(ADBXConnection);
end;


constructor TServerMethods1Client.Create(ADBXConnection: TDBXConnection; AInstanceOwner: Boolean);
begin
  inherited Create(ADBXConnection, AInstanceOwner);
end;


destructor TServerMethods1Client.Destroy;
begin
  FreeAndNil(FEchoStringCommand);
  FreeAndNil(FReverseStringCommand);
  FreeAndNil(FUploadFileCommand);
  inherited;
end;

end.

und hier mein Server:

Delphi-Quellcode:

unit ServerMethodsUnit1;

interface

uses System.SysUtils, System.Classes, Datasnap.DSServer, Datasnap.DSAuth;

type
{$METHODINFO ON}
  TServerMethods1 = class(TComponent)
  private
    { Private declarations }
  public
    { Public declarations }
    function EchoString(Value: string): string;
    function ReverseString(Value: string): string;
    procedure UploadFile(str: TStream; Store, FileName: String);
  end;
{$METHODINFO OFF}

implementation


uses System.StrUtils;

procedure TServerMethods1.UploadFile(str: TStream; Store, FileName: String);
var
  aFileStream: TFileStream;
  BytesReadCount: Integer;
  Buffer: array [1 .. 16 * 1024] of Byte;
  strPfad: String;
begin
  strPfad := 'C:\' + Store;
  if not DirectoryExists(strPfad) then
  begin
    MkDir(strPfad);
  end;
  aFileStream := TFileStream.Create(strPfad + '\' + FileName, fmCreate);
  try
    repeat
      BytesReadCount := str.Read(Buffer, SizeOf(Buffer));
      aFileStream.Write(Buffer, BytesReadCount);
    until (BytesReadCount < SizeOf(Buffer));
    str.Position := 0;
  finally
    aFileStream.Free;
  end;
end;

function TServerMethods1.EchoString(Value: string): string;
begin
  Result := Value;
end;

function TServerMethods1.ReverseString(Value: string): string;
begin
  Result := System.StrUtils.ReverseString(Value);
end;
end.

Was du sagst, mit dem InstanceOwner, verstehe ich. Aber was ist dann der Unterschied zwischen den beiden Funktionen?

Delphi-Quellcode:

procedure TForm2.Button1Click(Sender: TObject);
var
  aClient: TServerMethods1Client;
begin
  aClient := TServerMethods1Client.Create(SQLCOnnection1.DBXConnection);
  Try
    Edit1.Text := aClient.ReverseString(Edit1.Text);
  Finally
    aClient.Free;
  End;
 end;

procedure TForm2.Button2Click(Sender: TObject);
var
  aClient: TServerMethods1Client;
  aFileStream: TFileStream;
 begin
  aClient := TServerMethods1Client.Create(SQLCOnnection1.DBXConnection);
  Try
    aFileStream := TFileStream.Create(JvFilenameEdit1.Text, fmOpenRead);
    try
      aClient.UploadFile(aFileStream, 'Upload', ExtractFileName(JvFilenameEdit1.Text));
    except
      ShowMessage('Übertragung fehlerhaft!');
    end;
  Finally
    aFileStream.Free;
    aClient.Free;
  End;
end;

in beiden erzeuge ich das Objekt aClient auf die gleiche Weise. Demnach müßte ja in beiden Funktion der gleiche Fehler auftreten. Tut er aber nicht.