大数据流与DataSnap [英] big streams with DataSnap

问题描述

我试图在DataSnap服务器/客户端之间传输一些大流（〜1Mb），但没有用。我想了解Jim Tierney的代码（ http：// blogs。 embarcadero.com/jimtierney/2009/04/06/31461 ）没有运气，我甚至不能编译代码，因为一个丢失的图书馆，无论如何...

I'm trying to transfer some big streams (~1Mb) between DataSnap server/client but to no avail. I'm trying to understand the code of Jim Tierney (http://blogs.embarcadero.com/jimtierney/2009/04/06/31461) with no luck and i can't even compile the code because of a missing library, anyway ...

我可以接收的流的最大大小为64k，所以任何提示/想法/代码示例，您可以为周末程序员提供我会非常欢迎的。谢谢！

The max size of a stream i`m able to receive is 64k, so any tips/ideas/code samples you can provide for a weekend programmer like me will be very welcomed. Thank you!

我的服务器代码

function TsrvMethods.getStream(iCount: integer): TStream;
begin
  Result := dummyStream('0123456789', iCount);
end;

function dummyStream(sCnt: string; iCount: integer): TStream;
begin
  Result := TMemoryStream.Create;
  while iCount > 1 do begin
    Result.Write(Pointer(sCnt)^, Length(sCnt));
    Dec(iCount);
  end;
  Result.Seek(0, TSeekOrigin.soBeginning);
end;

我的客户端电话代码：

procedure TfrmMain.butStreamClick(Sender: TObject);
var
  sStr : TStream;
begin
  cycleConnection; //make sure we have an active connection

  with TsrvMethodsClient.Create( SQLConn.DBXConnection, False ) do begin
    sStr := getStream( Integer(SpinCount.Value) );
    Free;
  end;
  FreeAndNil(sStr);
end;

推荐答案

其实我觉得我得到了我发布这个作为一个答案也许其他人需要这个。

Actually, i think i`ve got it. I'm posting this as an answer maybe somebody else need this.

procedure TfrmMain.butStreamClick(Sender: TObject);
const
  iBufSize = 128;
var
  sStr : TStream;
  sMem : TMemoryStream;
  buf: PByte;
  iRead: integer;
begin
  cycleConnection;

  with TsrvMethodsClient.Create( SQLConn.DBXConnection, False ) do begin

    sStr := getStream( 500000 ); //500k stream

    GetMem(buf, iBufSize);
    sMem := TMemoryStream.Create;
    try
      repeat
        iRead := sStr.Read( Pointer(buf)^, iBufSize);

        if iRead > 0 then sMem.WriteBuffer( Pointer(buf)^, iRead);
        if iRead < iBufSize then break;
      until iRead < iBufSize;
    finally
      FreeMem(buf, iBufSize);
    end;

    Free;
  end;
  FreeAndNil(sStr);
  FreeAndNil(sMem);
end;

PS

通过DataSnap代码示例进行搜索我发现一个（速度相关）的改进是将iBufSize设置为61440（或等效的十六进制值$ F000），这似乎是最大的尺寸可以一次接收。如果接收流较大，则报告的大小将为-1，并且需要上面的代码来读取整个流。

Searching through DataSnap code samples i`ve found that one (speed related) improvement would be to have iBufSize set to 61440 (or equivalent hex value $F000) which seems to be the biggest size can be received in one go. If receiving stream is bigger then reported size will be -1 and the code above is needed to read the entire stream.

这篇关于大数据流与DataSnap的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！