pipe example server

#///////////////// message.nim /////////////
type
  MessageKind* = enum
    mkRotX, mkRotY, mkRotZ,
    mkPosX, mkPosY, mkPosZ,
    mkLength, mkWidth, mkHeight,
    mkSelectPart,
    mkQuit

  Message* = object
    kind*: MessageKind
    value*: cfloat

#////////////// server.nim ////////////
#
#Server Program for Win32 Named Pipes Example.
#Based on cpp example by Peter R. Bloomfield.
#
#For an explanation of the code, see the associated blog post:
#http://avidinsight.uk/2012/03/introduction-to-win32-named-pipes-cpp/
#https://github.com/avidinsight/win32-named-pipes-example/blob/master/src/server.cpp
#
#This code is made freely available under the MIT open source license
#(see accompanying LICENSE file for details).
#It is intended only for educational purposes. and is provide as-is with no
#guarantee about its reliability, correctness, or suitability for any purpose.
#
#
#TEST INSTRUCTIONS:
#
#Run this server program first.
#Before closing it, run the accompanying client program.
#

import winlean, os
import message

proc connectNamedPipe(hNamedPipe: Handle, lpOverlapped: pointer): WINBOOL
     {.importc: "ConnectNamedPipe", stdcall, dynlib: "kernel32".}
const
  pipeHeaderName = r"\\.\pipe\mypipe"

const
  DEFAULT_PIPE_SIZE = 65536'i32
  FILE_FLAG_FIRST_PIPE_INSTANCE = 0x00080000'i32
  PIPE_WAIT = 0x00000000'i32
  PIPE_TYPE_BYTE = 0x00000000'i32
  PIPE_READMODE_BYTE = 0x00000000'i32
  ERROR_PIPE_CONNECTED = 535
  ERROR_PIPE_BUSY = 231
  ERROR_BROKEN_PIPE = 109
  ERROR_PIPE_NOT_CONNECTED = 233

var pipe:Handle

proc createPipe*() =
  echo "Creating an instance of a named pipe..."
  # Create a pipe to send data
  var pipeName = newWideCString(pipeHeaderName)
  pipe = createNamedPipe(pipeName, # name of the pipe
                         PIPE_ACCESS_OUTBOUND, # 1-way pipe -- send only
                         PIPE_TYPE_BYTE, # send data as a byte stream
                         1, # only allow 1 instance of this pipe
                         0, # no outbound buffer
                         0, # no inbound buffer
                         0, # use default wait time
                         nil)


  if pipe == INVALID_HANDLE_VALUE:
    echo "Failed to create outbound pipe instance."
    let err = osLastError()
    if err.int32 != ERROR_PIPE_BUSY:
      raiseOsError(err)

  echo "Waiting for a client to connect to the pipe..."
  # This call blocks until a client process connects to the pipe
  var res = connectNamedPipe(pipe, nil)
  if res == 0:
    echo "Failed to make connection on named pipe."
    # look up error code here using GetLastError()
    discard closeHandle(pipe)
    # close the pipe

proc sendMessage*(data: ptr Message) =
  #echo "Sending data to pipe..."
  # This call blocks until a client process reads all the data
  var
    numBytesWritten:int32  = 0
    res:int32 = 0

  try:
    res = writeFile(pipe,      # handle to our outbound pipe
                    cast[pointer](data),      # data to send
                    sizeof(Message).int32,
                    numBytesWritten.addr, # will store actual amount of data sent
                    nil)
  except:
    return
  # if res > 0:
  #   echo "Number of bytes sent: ", numBytesWritten
  # else:
  #   echo "Failed to send data."

proc closePipe*() =
  # Close the pipe (automatically disconnects client too)
  echo "closing pipe"
  discard closeHandle(pipe)


proc test() =
  var msg = Message()

  createPipe()

  msg.kind = mkRotX
  msg.value = 1.5
  sendMessage(msg.addr)
  sleep(3000)

  msg.kind = mkRotz
  msg.value = 0.25
  sendMessage(msg.addr)
  sleep(3000)


  msg.kind = mkQuit
  sendMessage(msg.addr)

  closePipe()

when isMainModule:
  test()