How to use SAP NetWeaver RFC Library with Python - The Connection

[Stefan-Schnell]

I am not a Python programmer, but this week I had a discussion with a Python programmer about the using of actual SAP NetWeaver RFC library with Python. He told me, that he uses the library pysaprfc, which bases on the classic librfc32.dll. So I am a little bit surprised about his decision, because on the one hand Python offers via ctypes a complete interface to use the actual SAP NetWeaver RFC library. On the other hand is the classic RFC library (a little bit) outdated, e.g. it doesn't supports all data types - look here in the ActiveX context. I am searching in the internet and I am surprised again, I can't find an example snippet or something else. This was my launch to create the following examples.

 

The first example shows how to connect an SAP system:

#-Begin-----------------------------------------------------------------



#-Packages--------------------------------------------------------------

from ctypes import *



#-Structures------------------------------------------------------------

class RFC_ERROR_INFO(Structure):

  _fields_ = [("code", c_long),

              ("group", c_long),

              ("key", c_wchar * 128),

              ("message", c_wchar * 512),

              ("abapMsgClass", c_wchar * 21),

              ("abapMsgType", c_wchar * 2),

              ("abapMsgNumber", c_wchar * 4),

              ("abapMsgV1", c_wchar * 51),

              ("abapMsgV2", c_wchar * 51),

              ("abapMsgV3", c_wchar * 51),

              ("abapMsgV4", c_wchar * 51)]



class RFC_CONNECTION_PARAMETER(Structure):

  _fields_ = [("name", c_wchar_p),

              ("value", c_wchar_p)]



#-Main------------------------------------------------------------------

ErrInf = RFC_ERROR_INFO; RfcErrInf = ErrInf()

ConnParams = RFC_CONNECTION_PARAMETER * 5; RfcConnParams = ConnParams()



SAPNWRFC = "sapnwrfc.dll"

SAP = windll.LoadLibrary(SAPNWRFC)



#-Prototypes------------------------------------------------------------

SAP.RfcOpenConnection.argtypes = [POINTER(ConnParams), c_ulong, \

  POINTER(ErrInf)]

SAP.RfcOpenConnection.restype = c_void_p

SAP.RfcCloseConnection.argtypes = [c_void_p, POINTER(ErrInf)]

SAP.RfcCloseConnection.restype = c_ulong



#-Connection parameters-------------------------------------------------

RfcConnParams[0].name = "ASHOST"; RfcConnParams[0].value = "ABAP"

RfcConnParams[1].name = "SYSNR" ; RfcConnParams[1].value = "00"

RfcConnParams[2].name = "CLIENT"; RfcConnParams[2].value = "001"

RfcConnParams[3].name = "USER"  ; RfcConnParams[3].value = "BCUSER"

RfcConnParams[4].name = "PASSWD"; RfcConnParams[4].value = "minisap"



hRFC = SAP.RfcOpenConnection(RfcConnParams, 5, RfcErrInf)

if hRFC != None:



  windll.user32.MessageBoxW(None, "Check connection with TAC SMGW", \

    "", 0)



  #---------------------------------------------------------------------

  #-

  #- Check connection with TAC SMGW in the SAP system

  #-

  #---------------------------------------------------------------------



  rc = SAP.RfcCloseConnection(hRFC, RfcErrInf)



else:

  print(RfcErrInf.key)

  print(RfcErrInf.message)



#-End-------------------------------------------------------------------

 

The second example shows how to get the version number of the library:

# -*- coding: iso-8859-15 -*-

#-Begin-----------------------------------------------------------------



#-Include---------------------------------------------------------------

FileName = "sapnwrfc.py"

exec(compile(open(FileName).read(), FileName, "exec"))



#-Import----------------------------------------------------------------

import sys

import platform



#-Main------------------------------------------------------------------

MajorVersion = c_ulong(0)

MinorVersion = c_ulong(0)

PatchLevel = c_ulong(0)

Version = SAP.RfcGetVersion(MajorVersion, MinorVersion, PatchLevel)



print("MajorVersion: " + str(MajorVersion.value))

print("MinorVersion: " + str(MinorVersion.value))

print("PatchLevel: " + str(PatchLevel.value))

print("Version: " + Version)



del SAP



PyVer = sys.version_info

print("\nPython version: " + str(PyVer.major) + "." + \

  str(PyVer.minor) + "." + str(PyVer.micro) + " " + \

  str(platform.architecture()[0]))



print("Operating system: " + str(platform.system()) + " " + \

  str(platform.release()) + " " + str(platform.machine()))



#-End-------------------------------------------------------------------

As you can see I am a newbie in Python, but I think this snippets are a good precondition to intensify the using of actual SAP NetWeaver RFC library with Python directly. I developed this examples with the actual Python version 3.4.1, in an Windows environment with the actual SAP NetWeaver RFC library 720 PL24.

2015/09/16: Three days ago the new Python release 3.5.0 has been published. The method above works perfect with the new release.

2017/04/24: I check the method above with Python release 3.6.1 x64 and with the SAP NetWeaver RFC library 721 PL42 x64 and it works perfect.