Sending POST request with IWebBrowser2 in plain C

Question

I need to compile a POST request routine using IWebBrowser2 in plain C, the problem is that "the post data specified by PostData is passed as a SAFEARRAY Data Type structure. The VARIANT should be of type VT_ARRAY|VT_UI1 and point to a SAFEARRAY Data Type. The SAFEARRAY Data Type should be of element type VT_UI1, dimension one, and have an element count equal to the number of bytes of post data." as it says in https://learn.microsoft.com/en-us/previous-versions/aa752133(v=vs.85)

When i send the request to my local server it just dont receive the $_POST['name'] nor $_POST['sub'] variables, like i didnt send nothing

INT32
WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, INT32 nShowCmd)
{
  HRESULT HResult = 0;
  CLSID CLSID_IE;
  IWebBrowser2 *pWebBrowser;
  VARIANT vEmpty;
  VARIANT_BOOL vBusy;

  VariantInit(&vEmpty);
  CoInitializeEx(0, COINIT_MULTITHREADED);
  CoInitializeSecurity(NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_DEFAULT, RPC_C_IMP_LEVEL_IMPERSONATE, NULL, EOAC_NONE, NULL);
  CoCreateInstance(&CLSID_InternetExplorer, 0, CLSCTX_ALL, &IID_IWebBrowser2, &pWebBrowser);
  IWebBrowser2_put_Visible(pWebBrowser, VARIANT_FALSE);

  /* process the formulary data */
  LPSTR pPostData = NULL;
  CHAR strFormulary[] = "sub=gt&name=sdfs";
  LPSAFEARRAY FormularyArray = SafeArrayCreateVector(VT_UI1, 0, sizeof(strFormulary));
  VARIANT PostData = FormularyArray;

  SafeArrayAccessData(FormularyArray, (LPVOID*)&pPostData);
  memcpy(pPostData, &strFormulary, sizeof(strFormulary));
  SafeArrayUnaccessData(FormularyArray);

  /* Set the headers data */
  VARIANT Headers;
  V_VT(&Headers) = VT_BSTR;
  V_BSTR(&Headers) = SysAllocString(L"Content-Type: application/x-www-form-urlencodedrn");

  /* Set POST request */
  BSTR bstrURL = SysAllocString(L"http://192.168.100.44/user.php");
  IWebBrowser2_Navigate(pWebBrowser, bstrURL, &vEmpty, &vEmpty, &PostData, &Headers);

  // Wait for page to load
  do {
    LARGE_INTEGER TimeOut;
    UINT32 Milliseconds = 2000;
    TimeOut.QuadPart = UInt32x32To64( Milliseconds, 1000 );
    TimeOut.QuadPart *= -1;
    NtDelayExecution(FALSE, &TimeOut);
    IWebBrowser2_get_Busy(pWebBrowser, &vBusy);
  } while(vBusy);

  // Get IDispatch interface
  IDispatch* pDispatch;
  IWebBrowser2_get_Document(pWebBrowser, &pDispatch);
  IHTMLDocument2* pDocument;
  IDispatch_QueryInterface(pDispatch, &IID_IHTMLDocument2 , &pDocument);
  IHTMLElement* lpBodyElm;
  IHTMLDocument2_get_body(pDocument, &lpBodyElm);
  IHTMLElement* lpParentElm;
  IHTMLElement_get_parentElement(lpBodyElm, &lpParentElm);

  // Get Inner HTML content content of the request
  BSTR bstrBody;
  lpParentElm->lpVtbl->get_innerHTML(lpParentElm, &bstrBody);

  wprintf(L"%ls\n\n", bstrBody);

  cleanup:
  SysFreeString(bstrURL);
  IWebBrowser2_Quit(pWebBrowser);
  IWebBrowser2_Release(pWebBrowser);
  IDispatch_Release(pDispatch);
  IHTMLDocument2_Release(pDocument);
  IHTMLElement_Release(lpBodyElm);
  lpParentElm->lpVtbl->Release(lpParentElm);
  CoUninitialize();
  RtlExitUserProcess(STATUS_SUCCESS);
}

Answer 1

i solved it this way:

INT32
WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, INT32 nShowCmd)
{
    HRESULT HResult = 0;
    CLSID CLSID_IE;
    IWebBrowser2 *pWebBrowser;
    VARIANT vEmpty;
    VARIANT_BOOL vBusy;

    VariantInit(&vEmpty);
    CoInitializeEx(0, COINIT_MULTITHREADED);
    CoInitializeSecurity(NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_DEFAULT, RPC_C_IMP_LEVEL_IMPERSONATE, NULL, EOAC_NONE, NULL);
    CoCreateInstance(&CLSID_InternetExplorer, 0, CLSCTX_ALL, &IID_IWebBrowser2, &pWebBrowser);
    IWebBrowser2_put_Visible(pWebBrowser, VARIANT_FALSE);

    /* Set the POST data */
    VARIANT PostData;
    PostData.vt = VT_NULL;
    CHAR PostDataContent[] = "sub=gt&name=sdfs";
    UINT32 PostDatalenght = sizeof(PostDataContent);

    // Create safe array
    SAFEARRAY* psa = SafeArrayCreateVector(VT_UI1, 0, PostDatalenght);
    if (psa != NULL)
    {
        // Store elements into the SafeArray
        BYTE HUGEP* pByte = (PBYTE)&PostDataContent;
        HRESULT hr = S_OK;
        for (long i=0; i<PostDatalenght; i++){
            hr = SafeArrayPutElement(psa, &i, pByte);
            pByte++;
        }

        // Get a pointer to the elements of the array.
        SafeArrayAccessData(psa, (void HUGEP**)&pByte);
        PostData.vt = VT_ARRAY|VT_UI1;
        PostData.parray = psa;
    }


    /* Set the headers data */
    VARIANT Headers;
    V_VT(&Headers) = VT_BSTR;
    V_BSTR(&Headers) = SysAllocString(L"Content-Type: application/x-www-form-urlencoded");

    /* Set POST request */
    BSTR bstrURL = SysAllocString(L"http://192.168.100.44/user.php");
    IWebBrowser2_Navigate(pWebBrowser, bstrURL, &vEmpty, &vEmpty, &PostData, &Headers);

    // Wait for page to load
    do {
        LARGE_INTEGER TimeOut;
        UINT32 Milliseconds = 2000;
        TimeOut.QuadPart = UInt32x32To64( Milliseconds, 1000 );
        TimeOut.QuadPart *= -1;
        NtDelayExecution(FALSE, &TimeOut);
        IWebBrowser2_get_Busy(pWebBrowser, &vBusy);
    } while(vBusy);

    // Get IDispatch interface
    IDispatch* pDispatch;
    IWebBrowser2_get_Document(pWebBrowser, &pDispatch);
    IHTMLDocument2* pDocument;
    IDispatch_QueryInterface(pDispatch, &IID_IHTMLDocument2 , &pDocument);
    IHTMLElement* lpBodyElm;
    IHTMLDocument2_get_body(pDocument, &lpBodyElm);
    IHTMLElement* lpParentElm;
    IHTMLElement_get_parentElement(lpBodyElm, &lpParentElm);

    // Get Inner HTML content content of the request
    BSTR bstrBody;
    lpParentElm->lpVtbl->get_innerHTML(lpParentElm, &bstrBody);

    wprintf(L"%ls\n\n", bstrBody);

    cleanup:
    SysFreeString(bstrURL);
    IWebBrowser2_Quit(pWebBrowser);
    IWebBrowser2_Release(pWebBrowser);
    IDispatch_Release(pDispatch);
    IHTMLDocument2_Release(pDocument);
    IHTMLElement_Release(lpBodyElm);
    lpParentElm->lpVtbl->Release(lpParentElm);
    CoUninitialize();
    RtlExitUserProcess(STATUS_SUCCESS);
}