Come i client trovano e usano un punto di Connessione servizio

Nell'esempio di codice seguente viene illustrato come un'applicazione client cerca un punto SCP (Service Connessione ion Point) nel Catalogo globale. In questo esempio di codice l'applicazione client ha una stringa GUID hardcoded che identifica il servizio. Il programma di installazione del servizio ha archiviato la stessa stringa GUID di uno dei valori dell'attributo di parole chiave multivalore SCPs.

Questo esempio è costituito da due routine. La routine GetGC recupera un puntatore IDirectorySearch per un catalogo globale (GC). La routine ScpLocate usa i metodi IDirectorySearch per eseguire ricerche nel catalogo GC.

Il GC contiene una replica parziale di ogni oggetto nella foresta, ma non contiene tutti gli attributi SCP richiesti dal client. Prima di tutto, il client deve eseguire una ricerca nel catalogo globale per trovare SCP e recuperare il relativo DN. Il client usa quindi il DN di SCP per eseguire l'associazione a un puntatore IDirectoryObject su SCP. Il client chiama quindi il metodo IDirectoryObject::GetObjectAttributes per recuperare il resto degli attributi.

//***************************************************************************
//
//  ScpLocate()
//
//  All strings returned by ScpLocate must be freed by the caller using 
//  FreeADsStr after it is finished using them.
//
//***************************************************************************

DWORD ScpLocate (
    LPWSTR *ppszDN,                  // Returns distinguished name of SCP.
    LPWSTR *ppszServiceDNSName,      // Returns service DNS name.
    LPWSTR *ppszServiceDNSNameType,  // Returns type of DNS name.
    LPWSTR *ppszClass,               // Returns name of service class.
    USHORT *pusPort)                 // Returns service port.
{
    HRESULT hr;
    IDirectoryObject *pSCP = NULL;
    ADS_ATTR_INFO *pPropEntries = NULL;
    IDirectorySearch *pSearch = NULL;
    ADS_SEARCH_HANDLE hSearch = NULL;

    // Get an IDirectorySearch pointer for the Global Catalog. 
    hr = GetGCSearch(&pSearch);
    if (FAILED(hr)) 
    {
        fprintf(stderr,"GetGC failed 0x%x",hr);
        goto Cleanup;
    }

    // Set up a deep search.
    // Thousands of objects are not expected in this example, therefore
    // query for 1000 rows per page.
    ADS_SEARCHPREF_INFO SearchPref[2];
    DWORD dwPref = sizeof(SearchPref)/sizeof(ADS_SEARCHPREF_INFO);
    SearchPref[0].dwSearchPref =    ADS_SEARCHPREF_SEARCH_SCOPE;
    SearchPref[0].vValue.dwType =   ADSTYPE_INTEGER;
    SearchPref[0].vValue.Integer =  ADS_SCOPE_SUBTREE;

    SearchPref[1].dwSearchPref =    ADS_SEARCHPREF_PAGESIZE;
    SearchPref[1].vValue.dwType =   ADSTYPE_INTEGER;
    SearchPref[1].vValue.Integer =  1000;

    hr = pSearch->SetSearchPreference(SearchPref, dwPref);
    fprintf (stderr, "SetSearchPreference: 0x%x\n", hr);
    if (FAILED(hr))
    {
        fprintf (stderr, "Failed to set search prefs: hr:0x%x\n", hr);
        goto Cleanup;
    } 

    // Execute the search. From the GC get the distinguished name 
    // of the SCP. Use the DN to bind to the SCP and get the other 
    // properties.
    LPWSTR rgszDN[] = {L"distinguishedName"};

    // Search for a match of the product GUID.
    hr = pSearch->ExecuteSearch(    L"keywords=A762885A-AA44-11d2-81F1-00C04FB9624E",
                                    rgszDN,
                                    1,
                                    &hSearch);

    fprintf (stderr, "ExecuteSearch: 0x%x\n", hr);

    if (FAILED(hr)) 
    {
        fprintf (stderr, "ExecuteSearch failed: hr:0x%x\n", hr);
        goto Cleanup;
    } 

    // Loop through the results. Each row should be an instance of the 
    // service identified by the product GUID.
    // Add logic to select from multiple service instances.
    hr = pSearch->GetNextRow(hSearch);
    if (SUCCEEDED(hr) && hr !=S_ADS_NOMORE_ROWS) 
    {
        ADS_SEARCH_COLUMN Col;

        hr = pSearch->GetColumn(hSearch, L"distinguishedName", &Col);
        *ppszDN = AllocADsStr(Col.pADsValues->CaseIgnoreString);
        pSearch->FreeColumn(&Col);
        hr = pSearch->GetNextRow(hSearch);
    }

    // Bind to the DN to get the other properties.
    LPWSTR lpszLDAPPrefix = L"LDAP://";
    DWORD dwSCPPathLength = wcslen(lpszLDAPPrefix) + wcslen(*ppszDN) + 1;
    LPWSTR pwszSCPPath = new WCHAR[dwSCPPathLength];
    if(pwszSCPPath)
    {
        wcscpy_s(pwszSCPPath, lpszLDAPPrefix);
        wcscat_s(pwszSCPPath, *ppszDN);
    }       
    else
    {
        fprintf(stderr,"Failed to allocate a buffer");
        goto Cleanup;
    }               

    hr = ADsGetObject(  pwszSCPPath,
                        IID_IDirectoryObject,
                        (void**)&pSCP);

    // Free the string buffer
    delete pwszSCPPath;

    if (SUCCEEDED(hr)) 
    {
        // Properties to retrieve from the SCP object.
        LPWSTR rgszAttribs[]=
        {
            {L"serviceClassName"},
            {L"serviceDNSName"},
            {L"serviceDNSNameType"},
            {L"serviceBindingInformation"}
        };

        DWORD dwAttrs = sizeof(rgszAttribs)/sizeof(LPWSTR);
        DWORD dwNumAttrGot;
        hr = pSCP->GetObjectAttributes( rgszAttribs,
                                        dwAttrs,
                                        &pPropEntries,
                                        &dwNumAttrGot);
        if(FAILED(hr)) 
        {
            fprintf (stderr, "GetObjectAttributes Failed. hr:0x%x\n", hr);
            goto Cleanup;
        }

        // Loop through the entries returned by GetObjectAttributes 
        // and save the values in the appropriate buffers. 
        for (int i = 0; i < (LONG)dwAttrs; i++) 
        {
            if ((wcscmp(L"serviceDNSName", pPropEntries[i].pszAttrName)==0) &&
                (pPropEntries[i].dwADsType == ADSTYPE_CASE_IGNORE_STRING)) 
            {
                *ppszServiceDNSName = AllocADsStr(pPropEntries[i].pADsValues->CaseIgnoreString);
            }

            if ((wcscmp(L"serviceDNSNameType", pPropEntries[i].pszAttrName)==0) &&
                (pPropEntries[i].dwADsType == ADSTYPE_CASE_IGNORE_STRING)) 
            {
                *ppszServiceDNSNameType = AllocADsStr(pPropEntries[i].pADsValues->CaseIgnoreString);
            }

            if ((wcscmp(L"serviceClassName", pPropEntries[i].pszAttrName)==0) &&
                (pPropEntries[i].dwADsType == ADSTYPE_CASE_IGNORE_STRING)) 
            {
                *ppszClass = AllocADsStr(pPropEntries[i].pADsValues->CaseIgnoreString);
            }

            if ((wcscmp(L"serviceBindingInformation", pPropEntries[i].pszAttrName)==0) &&
                (pPropEntries[i].dwADsType == ADSTYPE_CASE_IGNORE_STRING)) 
            {
                *pusPort=(USHORT)_wtoi(pPropEntries[i].pADsValues->CaseIgnoreString);
            }
        }
    }

Cleanup:
    if (pSCP) 
    {
        pSCP->Release();
        pSCP = NULL;
    }

    if (pPropEntries)
    {
        FreeADsMem(pPropEntries);
        pPropEntries = NULL;
    }

    if (pSearch)
    {
        if (hSearch)
        {
            pSearch->CloseSearchHandle(hSearch);
            hSearch = NULL;
        }
        
        pSearch->Release();
        pSearch = NULL;
    }

    return hr;
}

//***************************************************************************
//
//  GetGCSearch()
//
//  Retrieves an IDirectorySearch pointer for a Global Catalog (GC)
//
//***************************************************************************

HRESULT GetGCSearch(IDirectorySearch **ppDS)
{
    HRESULT hr;
    IEnumVARIANT *pEnum = NULL;
    IADsContainer *pCont = NULL;
    IDispatch *pDisp = NULL;
    VARIANT var;
    ULONG lFetch;

    *ppDS = NULL;

    // Bind to the GC: namespace container object. The true GC DN 
    // is a single immediate child of the GC: namespace, which must 
    // be obtained using enumeration.
    hr = ADsOpenObject( L"GC:",
                        NULL,
                        NULL,
                        ADS_SECURE_AUTHENTICATION, // Use Secure Authentication.
                        IID_IADsContainer,
                        (void**)&pCont);
    if (FAILED(hr)) 
    {
        _tprintf(TEXT("ADsOpenObject failed: 0x%x\n"), hr);
        goto cleanup;
    } 

    // Get an enumeration interface for the GC container. 
    hr = ADsBuildEnumerator(pCont, &pEnum);
    if (FAILED(hr)) 
    {
        _tprintf(TEXT("ADsBuildEnumerator failed: 0x%x\n"), hr);
        goto cleanup;
    } 

    // Now enumerate. There is only one child of the GC: object.
    hr = ADsEnumerateNext(pEnum, 1, &var, &lFetch);
    if (FAILED(hr)) 
    {
        _tprintf(TEXT("ADsEnumerateNext failed: 0x%x\n"), hr);
        goto cleanup;
    } 

    if ((hr == S_OK) && (lFetch == 1))
    {
        pDisp = V_DISPATCH(&var);
        hr = pDisp->QueryInterface( IID_IDirectorySearch, (void**)ppDS); 
    }

cleanup:
    if (pEnum)
    {
        ADsFreeEnumerator(pEnum);
        pEnum = NULL;
    }

    if (pCont)
    {
        pCont->Release();
        pCont = NULL;
    }
    
    if (pDisp)
    {
        pDisp->Release();
        pDisp = NULL;
    }

    return hr;
}