Use Named Pipes to Send Chunks of Binary Data

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Question:

I need to transfer a graphics file from a server to a client machine using named pipes, but there seems to be alimitation on the size of data that can be shared.

Answer:

This is a previously unknown limitation in the WinBatch Named Pipe implementation. It just can't handle data chunks of the size you are using. So you will need to break up your data into small chunks (maybe something less than 46K) or go the WinSock route. The Named Pipe issue will be addressed either by documentation or implementation change in a future release.

Here is a crude hack (bugs included at no extra charge) of your script with a simple dice and slice added to illustrate how it might work. With appropriate computer and file names, it worked in very limited testing...

 ;------------
 ; SERVER.WBT
 ;------------
 _FileName = `c:\Clipboard01.jpg`

 pipename="\\.\pipe\fluggle"
 timeout = -1
 t_StartTime = GetExactTime()
 IntControl(12,5,0,0,0);terminate quietly
 notice = StrCat(@CRLF,@CRLF,"[ Press CTRL+BREAK to exit script ]")
 BoxOpen("Time Server","Initializing - Awaiting connect from Client")
 WinPlace(10,10,300,150, ``)

 While @TRUE ; General Server loop
    pipehandle = PipeServerCreate(pipename,timeout)
    If pipehandle=="*ERROR*" || pipehandle=="*TIMER*" Then Continue
    readinfo = PipeServerRead(pipehandle, timeout)
    If readinfo=="*ERROR*" || readinfo=="*TIMER*"
       PipeServerClose(pipehandle,0)
       Continue ; try again
    EndIf
    If readinfo == "GET_FILE"
       bb = BinaryAlloc(FileSize(_FileName))
       BinaryRead(bb,_FileName)
       response = BinaryPeekHex(bb, 0, BinaryEodGet(bb))
       nChunks = (StrLen(response)/32767)
       For x = 0 To nChunks
          strChunk = StrSub( response,(x*32767)+1 , 32767 )
          rslt=PipeServerWrite(pipehandle,strChunk )
       Next
       PipeServerWrite(pipehandle,"DATA_DONE")
    EndIf
    rslt=PipeServerWrite(pipehandle,response)
    t_EndTime = GetExactTime()
    BoxText(@CRLF:@TAB:`Data sent. Time start [%t_StartTime%]   Time End [%t_EndTime%]`)
    PipeServerClose(pipehandle, timeout)
 EndWhile
 Message("Server","Exited")
 Exit

;------------
 ; CLIENT.WBT
 ;------------

 _ServerNetbiosName = `MyComputerName`
 _FileName = `c:\Clipboard01.jpg`
 _GraphicsApp = `mspaint.exe`

 SERVER = _ServerNetbiosName ; Or "." for the local machine
 pipename = "fluggle"
 pipepath = StrCat("\\",SERVER,"\pipe\",pipename)
 querydata = "GET_FILE"
 timeout = -1
 IntControl(12,5,0,0,0);terminate quietly
 notice = StrCat(@CRLF,@CRLF,"[ Press CTRL+BREAK to exit script ]")
 BoxOpen("Client","Initializing connection to server...")
 WinPlace(10,300,300,450,``)

 While @TRUE
   pipehandle = PipeClientOpen(pipepath,timeout)
   If pipehandle=="*ERROR*" Then Message("error #", PipeInfo(0, 0) )
   If pipehandle=="*ERROR*" || pipehandle=="*TIMER*" Then Continue ; try again
   t_Start = GetExactTime()
   data = ""
   temp=PipeClientSendRecvData(pipehandle, querydata,timeout)
   While @TRUE
      If temp == "DATA_DONE" || temp == _err Then Break
      data = data:temp
      BoxText(`Received %_cnt% of %_total%`)
      _cnt = _cnt + 1
      temp=PipeClientSendRecvData(pipehandle, "",timeout)
   EndWhile
   t_End = GetExactTime()
   t_Size = StrLen(data)
   BoxText(`RECEIVED %t_Size% bytes.`)
   PipeClientClose(pipehandle)
   bb = BinaryAlloc(500000)
   BinaryPokeHex(bb, 0, data)
   BinaryWrite(bb, _FileName)
   BinaryFree(bb)
   Run(_GraphicsApp,_FileName)
   ;-----
   Break
   ;-----
 EndWhile
 Message("Client","Exited")
 Exit

Article ID:   W18222

Filename:   Use Named Pipes to Send Chunks of Binary Data.txt

File Created: 2011:09:21:10:41:20

Last Updated: 2011:09:21:10:41:20

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