RFC Server Programming Example (SAP-Bibliothek - Komponenten der SAP-Kommunikationstechnologie)

RFC Server Programming Example

In the following section you can find a programming example using basic elements of RFC Server programs like registering the server, installing a server function and error handling:

#include <stdlib.h>

#include <stdio.h>

#include "sapnwrfc.h"

static int listening = 1;

Transaction SE37 in the AS ABAP does not yet allow to set complex inputs, so in order to test

this example, you will probably need to write a short ABAP report, which sets a few

input lines for IMPORT_TAB and then does a

CALL FUNCTION 'STFC_DEEP_TABLE' DESTINATION 'MY_SERVER'

EXPORTING

import_tab = imtab

IMPORTING

export_tab = extab

resptext = text

EXCEPTIONS

system_failure = 1 MESSAGE mes.

This also allows to catch the detail texts for SYSTEM_FAILURES.

Note: STFC_DEEP_TABLE exists only from SAP_BASIS release 6.20 on.

void errorHandling(RFC_RC rc, SAP_UC description[], RFC_ERROR_INFO* errorInfo, RFC_CONNECTION_HANDLE connection){

printfU(cU("%s: %d\n"), description, rc);

printfU(cU("%s: %s\n"), errorInfo->key, errorInfo->message);

// It's better to close the TCP/IP connection cleanly, than to just let the

// backend get a "Connection reset by peer" error...

if (connection != NULL) RfcCloseConnection(connection, errorInfo);

exit(1);

}

RFC_RC SAP_API stfcDeepTableImplementation(RFC_CONNECTION_HANDLE rfcHandle, RFC_FUNCTION_HANDLE funcHandle, RFC_ERROR_INFO* errorInfoP){

RFC_ATTRIBUTES attributes;

RFC_TABLE_HANDLE importTab = 0;

RFC_STRUCTURE_HANDLE tabLine = 0;

RFC_TABLE_HANDLE exportTab = 0;

RFC_ERROR_INFO errorInfo ;

RFC_CHAR buffer[257]; //One for the terminating zero

RFC_INT intValue;

RFC_RC rc;

unsigned tabLen = 0, strLen;

unsigned i = 0;

buffer[256] = 0;

printfU(cU("\n*** Got request for STFC_DEEP_TABLE from the following system: ***\n"));

/*If you want to include an authorization check for your RFC server according to SAP Note 1058327, insert it now:*/

RfcGetConnectionAttributes(rfcHandle, &attributes, &errorInfo);

printfU(cU("System ID: %s\n"), attributes.sysId);

printfU(cU("System No: %s\n"), attributes.sysNumber);

printfU(cU("Mandant : %s\n"), attributes.client);

printfU(cU("Host : %s\n"), attributes.partnerHost);

printfU(cU("User : %s\n"), attributes.user);

//Print the Importing Parameter

printfU(cU("\nImporting Parameter:\n"));

RfcGetTable(funcHandle, cU("IMPORT_TAB"), &importTab, &errorInfo);

RfcGetRowCount(importTab, &tabLen, &errorInfo);

printfU(cU("IMPORT_TAB (%d lines)\n"), tabLen);

for (i=0; i<tabLen; i++){

RfcMoveTo(importTab, i, &errorInfo);

printfU(cU("\t\t-line %d\n"), i);

RfcGetInt(importTab, cU("I"), &intValue, &errorInfo);

printfU(cU("\t\t\t-I:\t%d\n"), intValue);

RfcGetString(importTab, cU("C"), buffer, 11, &strLen, &errorInfo);

printfU(cU("\t\t\t-C:\t%s\n"), buffer);

// Check for the stop flag:

if (i==0 && strncmpU(cU("STOP"), buffer, 4) == 0) listening = 0;

RfcGetStringLength(importTab, cU("STR"), &strLen, &errorInfo);

if (strLen > 256) printfU(cU("STRING length bigger than 256: %d. Omitting the STR field...\n"), strLen);

else{

RfcGetString(importTab, cU("STR"), buffer, 257, &strLen, &errorInfo);

printfU(cU("\t\t\t-STR:\t%s\n"), buffer);

}

RfcGetStringLength(importTab, cU("XSTR"), &strLen, &errorInfo);

if (strLen > 128) printfU(cU("XSTRING length bigger than 128: %d. Omitting the XSTR field...\n"), strLen);

else{

RfcGetString(importTab, cU("XSTR"), buffer, 257, &strLen, &errorInfo);

printfU(cU("\t\t\t-XSTR:\t%s\n"), buffer);

}

//Now set the Exporting Parameters

printfU(cU("\nSetting values for Exporting Parameters:\n"));

printfU(cU("Please enter a value for RESPTEXT:\n> "));

getsU(buffer);

RfcSetChars(funcHandle, cU("RESPTEXT"), buffer, strlenU(buffer), &errorInfo);

printfU(cU("\nPlease enter the number of lines in EXPORT_TAB:\n> "));

getsU(buffer);

tabLen = atoiU(buffer);

RfcGetTable(funcHandle, cU("EXPORT_TAB"), &exportTab, &errorInfo);

for (i=0; i<tabLen; i++){

tabLine = RfcAppendNewRow(exportTab, &errorInfo);

printfU(cU("Line %d\n"), i);

printfU(cU("\tPlease enter a value for C [CHAR10]:> "));

getsU(buffer);

RfcSetChars(tabLine, cU("C"), buffer, strlenU(buffer), &errorInfo);

printfU(cU("\tPlease enter a value for I [INT4]:> "));

getsU(buffer);

RfcSetInt(tabLine, cU("I"), atoiU(buffer), &errorInfo);

printfU(cU("\tPlease enter a value for STR [STRING]:> "));

fgetsU(buffer, 257, stdin); // For these fields better make sure, the user doesn't bust our buffer...

strLen = strlenU(buffer) - 1;

// In contrast to gets, fgets includes the linebreak... Very consistent...

RfcSetString(tabLine, cU("STR"), buffer, strLen, &errorInfo);

mark: printfU(cU("\tPlease enter a value for XSTR [XSTRING]:> "));

fgetsU(buffer, 257, stdin);

strLen = strlenU(buffer) - 1;

// In contrast to gets, fgets includes the linebreak... Very consistent...

rc = RfcSetString(tabLine, cU("XSTR"), buffer, strLen, &errorInfo);

if (rc != RFC_OK){

printfU(cU("\tInvalid value for XSTR. Please only use hex digits 00 - FF.\n"));

goto mark;

}

printfU(cU("**** Processing of STFC_DEEP_TABLE finished ***\n\n"));

return RFC_OK;

}

int mainU(int argc, SAP_UC** argv){

RFC_RC rc;

RFC_FUNCTION_DESC_HANDLE stfcDeepTableDesc;

RFC_CONNECTION_PARAMETER repoCon[8], serverCon[3];

RFC_CONNECTION_HANDLE repoHandle, serverHandle;

RFC_ERROR_INFO errorInfo;

serverCon[0].name = cU("program_id"); serverCon[0].value = cU("MY_SERVER");

serverCon[1].name = cU("gwhost"); serverCon[1].value = cU("binmain");

serverCon[2].name = cU("gwserv"); serverCon[2].value = cU("sapgw53");

repoCon[0].name = cU("client"); repoCon[0].value = cU("000");

repoCon[1].name = cU("user"); repoCon[1].value = cU("user");

repoCon[2].name = cU("passwd"); repoCon[2].value = cU("****");

repoCon[3].name = cU("lang"); repoCon[3].value = cU("DE");

repoCon[4].name = cU("ashost"); repoCon[4].value = cU("binmain");

repoCon[5].name = cU("sysnr"); repoCon[5].value = cU("53");

printfU(cU("Logging in..."));

repoHandle = RfcOpenConnection (repoCon, 6, &errorInfo);

if (repoHandle == NULL) errorHandling(errorInfo.code, cU("Error in RfcOpenConnection()"), &errorInfo, NULL);

printfU(cU(" ...done\n"));

printfU(cU("Fetching metadata..."));

stfcDeepTableDesc = RfcGetFunctionDesc(repoHandle, cU("STFC_DEEP_TABLE"), &errorInfo);

// Note: STFC_DEEP_TABLE exists only from SAP_BASIS release 6.20 on

if (stfcDeepTableDesc == NULL) errorHandling(errorInfo.code, cU("Error in Repository Lookup"), &errorInfo, repoHandle);

printfU(cU(" ...done\n"));

printfU(cU("Logging out..."));

RfcCloseConnection(repoHandle, &errorInfo);

printfU(cU(" ...done\n"));

rc = RfcInstallServerFunction(NULL, stfcDeepTableDesc, stfcDeepTableImplementation, &errorInfo);

if (rc != RFC_OK) errorHandling(rc, cU("Error Setting "), &errorInfo, repoHandle);

printfU(cU("Registering Server..."));

serverHandle = RfcRegisterServer(serverCon, 3, &errorInfo);

if (serverHandle == NULL) errorHandling(errorInfo.code, cU("Error Starting RFC Server"), &errorInfo, NULL);

printfU(cU(" ...done\n"));

printfU(cU("Starting to listen...\n\n"));

while(RFC_OK == rc || RFC_RETRY == rc || RFC_ABAP_EXCEPTION == rc){

rc = RfcListenAndDispatch(serverHandle, 120, &errorInfo);

printfU(cU("RfcListenAndDispatch() returned %s\n"), RfcGetRcAsString(rc));

switch (rc){

case RFC_RETRY: // This only notifies us, that no request came in within the timeout period.

// We just continue our loop.

printfU(cU("No request within 120s.\n"));

break;

case RFC_ABAP_EXCEPTION: // Our function module implementation has returned RFC_ABAP_EXCEPTION.

// This is equivalent to an ABAP function module throwing an ABAP Exception.

// The Exception has been returned to the SAP system and our connection is still open.

// So we just loop around.

printfU(cU("ABAP_EXCEPTION in implementing function: %s\n"), errorInfo.key);

break;

case RFC_NOT_FOUND: // The SAP system tried to invoke a function module, for which we did not supply

// an implementation. The SAP system has been notified of this through a SYSTEM_FAILURE,

// so we need to refresh our connection.

printfU(cU("Unknown function module: %s\n"), errorInfo.message);

case RFC_EXTERNAL_FAILURE: // Our function module implementation raised a SYSTEM_FAILURE. In this case

// the connection needs to be refreshed as well.

printfU(cU("SYSTEM_FAILURE has been sent to backend.\n\n"));

case RFC_ABAP_MESSAGE: // And in this case a fresh connection is needed as well

serverHandle = RfcRegisterServer(serverCon, 3, &errorInfo);

rc = errorInfo.code;

break;

}

// This allows us to shutdown the RFC Server from the SAP system. The implementation of STFC_DEEP_TABLE

// will set listening to false, if IMPORT_TAB-C == STOP.

if (!listening){

RfcCloseConnection(serverHandle, NULL);

break;

}

return 0;

}