Question

我继承了一个使用CppWebBrowser控件的旧应用程序应用程序一直使用:: Navigate方法进行GET请求，但现在我需要开始将它用于POST;但是，现有代码不适用于POST。我使用这些数据类型的知识有限但我怀疑它与CString到VT_ARRAY | VT_UI1转换有关。

void WebPostData(TCppWebBrowser *CppWebBrowser, CString sURL, CString sPostData)
{
    BSTR bstrHeaders = NULL;
    TVariant vFlags = { 0 }, vTargetFrameName = { 0 }, vPostData = { 0 }, vHeaders = { 0 };
    LPSAFEARRAY psa;
    LPCTSTR cszPostData = sPostData;
    UINT cElems = lstrlen(cszPostData);
    LPSTR pPostData;
    LPVARIANT pvPostData;

        bstrHeaders = SysAllocString(L"Content-Type: application/x-www-form-urlencodedrn");
        if (!bstrHeaders){
            Application->MessageBox("Could not allocate bstrHeaders", "Warning", MB_OK | MB_ICONWARNING);
            return;
        }

        V_VT(&vHeaders) = VT_BSTR;
        V_BSTR(&vHeaders) = bstrHeaders;

        pvPostData = vPostData;

        if (pvPostData){
            VariantInit(pvPostData);

            psa = SafeArrayCreateVector(VT_UI1, 0, cElems);
            if (!psa){
                return;
            }

            SafeArrayAccessData(psa, (LPVOID*)&pPostData);
            memcpy(pPostData, cszPostData, cElems);
            SafeArrayUnaccessData(psa);

            V_VT(pvPostData) = VT_ARRAY | VT_UI1;
            V_ARRAY(pvPostData) = psa;
        }

        CppWebBrowser->Navigate((TVariant)sURL, &vFlags, &vTargetFrameName, &vPostData, &vHeaders);
}

Answer 1

您展示的代码是从此C ++ Builder示例中复制的：

How to post data using TCppWebBrowser in C++Builder

CString是一个MFC类，但C ++ Builder不支持MFC。原始代码使用System::String代替，这是一个C ++ Builder类。那么，您是否尝试将此代码转换为Visual Studio？或者你真的在使用C ++ Builder吗？你没说。

我将假设您正在使用C ++ Builder，否则您必须重新编写Visual Studio类的代码。

因此，让我们首先将CString更改回String。现在，根据您使用的C ++ Builder版本，String是 ANSI （C ++ Builder 3-2007）或 UTF-16 （C ++ Builder 2009+）。在后一种情况下，有一个_DELPHI_STRING_UNICODE预编译器定义。

application/x-www-form-urlencoded类型通常不以UTF-16格式发送，并且无法保证Web服务器能够处理它。所以我建议你将sPostData数据转换为UTF-8，然后你可以创建一个UTF-8字节的VT_UI1数组：

#ifndef _DELPHI_STRING_UNICODE
inline bool NeedsUTF8(String s)
{
    // String is 1-indexed
    for (int i = 1; i <= s.Length(); ++i)
    {
        int ch = s[i];
        if (ch > 0x7F) return true;
    }
    return false;
}
#endif

void WebPostData(TCppWebBrowser *CppWebBrowser, String sURL, String sPostData)
{
    TVariant vFlags, vTargetFrameName, vPostData, vHeaders;

    // note: UTF8String was added in C++Builder 6,
    // use AnsiString in C++Builder 3-5 instead
    UTF8String utf8;

    #ifdef _DELPHI_STRING_UNICODE
    // C++Builder 2009+, convert from UTF-16 to UTF-8 directly
    utf8 = sPostData;
    #else
    // C++Builder 3-2007, check if ASCII or ANSI
    if (NeedsUTF8(sPostData))
    {
        // ANSI, so convert from ANSI to UTF-16 to UTF-8,
        // but you have to do the last step manually
        WideString wPostData(sPostData);
        int len = WideCharToMultiByte(CP_UTF8, wPostData.c_bstr(), wPostData.Length(), NULL, 0, NULL, NULL);
        utf8.SetLength(len);
        WideCharToMultiByte(CP_UTF8, wPostData.c_bstr(), wPostData.Length(), utf8.c_str(), len, NULL, NULL);
    }
    else
    {
        // ASCII, compatible with UTF-8 as-is
        utf8 = sPostData;
    }
    #endif

    LPSAFEARRAY psa = SafeArrayCreateVector(VT_UI1, 0, utf8.Length());
    if (!psa)
        return;

    // TVariant takes ownership of a safearray
    vPostData = psa;

    // TVariant takes ownership of a copy of a WideString's BSTR
    vHeaders = WideString("Content-Type: application/x-www-form-urlencoded;charset=utf-8\r\n");

    LPVOID pPostData;
    if (FAILED(SafeArrayAccessData(psa, &pPostData)))
        return;

    memcpy(pPostData, utf8.c_str(), utf8.Length());
    SafeArrayUnaccessData(psa);

    CppWebBrowser->Navigate((TVariant)sURL, &vFlags, &vTargetFrameName, &vPostData, &vHeaders);
}

如何将CString转换为VT_ARRAY | VT_UI1

1 个答案: