Example Code for Using LDAP VLV

The following code example shows how to create and use a VLV control in LDAP.

// Add Wldap32.lib to your project.
// Add Wldap32.dll to your project.

#include "stdafx.h"
#define SECURITY_WIN32
#include "windows.h"
#include "stdio.h"
#include "winldap.h"
#include "rpc.h"
#include "rpcdce.h"
#include "security.h"
#include "stdio.h"
const size_t newsize = 100;

// Entry point for application
void __cdecl main (int argc, char* argv[])
{
 PWCHAR hostName = NULL;
 LDAP* pLdapConnection = NULL;
 ULONG version = LDAP_VERSION3;
 ULONG ldapErr;
 INT returnCode = 0;
 ULONG connectSuccess = 0;

 // Pass in the host name. If no host name 
 // was passed, set the pointer to NULL to use serverless
 // binding.
 if (argc > 1)
 {
 // Convert argv[] to a wchar_t*
 size_t origsize = strlen(argv[1]) + 1;
 size_t convertedChars = 0;
 wchar_t wcstring[newsize];
 mbstowcs_s(&convertedChars, wcstring, origsize, argv[1], _TRUNCATE);
 wcscat_s(wcstring, L" (wchar_t *)");
 hostName = wcstring;
 }
 else
 {
 hostName = NULL;
 }

 // Initialize a session. LDAP_PORT is the default port, 389.
 pLdapConnection = ldap_init(hostName, LDAP_PORT);

 if (pLdapConnection == NULL)
 {
 // Set the HRESULT based on the Windows error code.
 char hr = HRESULT_FROM_WIN32(GetLastError());
 printf("ldap_init failed with 0x%x.\n",hr);
 goto error_exit;
 }
 else
 printf("ldap_init succeeded \n");

 // Set the version to 3.0 (default is 2.0).
 returnCode = ldap_set_option(pLdapConnection,
 LDAP_OPT_PROTOCOL_VERSION,
 (void*)&version);
 if(returnCode != LDAP_SUCCESS)
 {
 printf("SetOption Error:%0X\n", version);
 goto error_exit;
 }

 // Connect to the server.
 connectSuccess = ldap_connect(pLdapConnection, NULL);
 if(connectSuccess != LDAP_SUCCESS)
 {
 printf("ldap_connect failed with 0x%x.\n",connectSuccess);
 goto error_exit;
 }

 // Bind with current credentials (login credentials). Be
 // aware that the password itself is never sent over the 
 // network, and encryption is not used.
 returnCode = ldap_bind_s(pLdapConnection, NULL, NULL,
 LDAP_AUTH_NEGOTIATE);
 if (returnCode != LDAP_SUCCESS)
 {
 goto error_exit;
 }

 // Create the VLV control and send it to the server.
 LDAPVLVInfo vlvInfo;
 PLDAPControl pvlvCtrl;
 PLDAPControl psortCtrl;
 PLDAPControl ctrlArr[3];

 // Enter the members of the VLV control.
 vlvInfo.ldvlv_after_count = 1;
 vlvInfo.ldvlv_attrvalue = NULL;
 vlvInfo.ldvlv_before_count = 1;
 vlvInfo.ldvlv_context = NULL;
 vlvInfo.ldvlv_count = 0;
 vlvInfo.ldvlv_extradata = NULL;
 vlvInfo.ldvlv_offset = 2;
 vlvInfo.ldvlv_version = LDAP_VLVINFO_VERSION;

 ldapErr = ldap_create_vlv_control(pLdapConnection,
 &vlvInfo,
 TRUE,
 &pvlvCtrl);

 printf("Create VLV control returned 0x%x\n",ldapErr);
 if (LDAP_SUCCESS != ldapErr)
 return;

 // Create a sort control and attach it.
 LDAPSortKey sortkeys;
 PLDAPSortKey sortkeyList[2];

 sortkeys.sk_attrtype = L"name";
 sortkeys.sk_matchruleoid = NULL;
 sortkeys.sk_reverseorder = FALSE;

 sortkeyList[0] = &sortkeys;
 sortkeyList[1] = NULL;

 ldapErr = ldap_create_sort_control(pLdapConnection,
 sortkeyList,
 TRUE,
 &psortCtrl);

 printf("Create Sort control returned 0x%x\n",ldapErr);
 if (LDAP_SUCCESS != ldapErr)
 return;

 // Send the VLV control, with a search request, to the server.
 ctrlArr[0] = psortCtrl;
 ctrlArr[1] = pvlvCtrl;
 ctrlArr[2] = NULL;
 PLDAPMessage pRes;

 ldapErr = ldap_search_ext_s(pLdapConnection,
 L"OU=Users,DC=DCname,DC=Fabrikam,DC=com",
 LDAP_SCOPE_SUBTREE,
 L"objectClass=*",
 NULL,
 1,
 ctrlArr,
 NULL,
 NULL,
 0,
 &pRes);

 printf("Ldap search returned 0x%x\n",ldapErr);
 
 // Choose the control returned from the server.
 PLDAPControl *pvlvResponse = NULL;
 ldapErr = ldap_parse_result(pLdapConnection,
 pRes,
 NULL,
 NULL,
 NULL,
 NULL,
 &pvlvResponse,
 FALSE);

 printf("Ldap parse_result returned 0x%x\n",ldapErr);

 // Parse the VLV control returned from the server.
 ULONG targetPos =0;
 ULONG listCount = 0;
 int errCode = LDAP_SUCCESS;
 PBERVAL context = NULL;


 ldapErr = ldap_parse_vlv_control(pLdapConnection,
 pvlvResponse,
 &targetPos,
 &listCount,
 &context,
 &errCode);

 printf("Ldap parse vlv control returned 0x%x\n",ldapErr);
 printf("TargetPos = %d\n", targetPos);
 printf("ListCount = %d\n", listCount);
 printf("errcode = 0x%x\n", errCode);

 // Free resources
 ldap_unbind(pLdapConnection);
 ldap_control_free(pvlvCtrl);
 ldap_control_free(psortCtrl);
 ldap_msgfree(pRes);
 ldap_controls_free(pvlvResponse);
 ber_bvfree(context);

 return;

 // On error perform normal cleanup, set return flag to error, and exit.
 error_exit:
 ldap_unbind(pLdapConnection);
 return;
}