Question

我正在研究一个程序，它需要在加载之前检查页面是否存在（所以没有太多异国情调）。

一切正常，但我无法让HttpQueryInfo返回页面的有效状态代码。返回的状态代码为： 1875378224

产生问题的代码：

DWORD headerBuffSize = sizeof(DWORD);
DWORD statusCode;
//Check existance of page (for 404 error)
if(!HttpQueryInfo(hRequestHandle,
                  HTTP_QUERY_STATUS_CODE,
                  &statusCode,
                  &headerBuffSize,
                  NULL))
    return 4;

if(statusCode == HTTP_STATUS_NOT_FOUND)
    cout << "We got a 404 error" << endl;

cout << "Got Status code: " << statusCode << endl; //1875378224 everywhere
cout << "404 status code: " << HTTP_STATUS_NOT_FOUND << endl; //What it should be getting

我不知道该怎么做;我已将自己的代码与在线的几个示例进行比较，看起来应该工作，尽管我可能犯了一个愚蠢的错误。

谢谢！

Answer 1

HttpQueryInfo的Microsoft文档提示您可以获得DWORD HTTP_QUERY_STATUS_CODE提供的HTTP_QUERY_FLAG_NUMBER DWORD statusCode = 0; DWORD length = sizeof(DWORD); HttpQueryInfo( hRequestHandle, HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER, &statusCode, &length, NULL );。以下代码段显示了如何：

{{1}}

Answer 2

HttpQueryInfo从响应标头中检索到的信息始终是文本字符串。

int statusCode;
char responseText[256]; // change to wchar_t for unicode
DWORD responseTextSize = sizeof(responseText);

//Check existance of page (for 404 error)
if(!HttpQueryInfo(hRequestHandle,
                  HTTP_QUERY_STATUS_CODE,
                  &responseText,
                  &responseTextSize,
                  NULL))
    return 4;
statusCode = atoi(responseText);

Answer 3

我最近才开始工作 - 发现网络上的大多数示例都不适用于我，即使是MSDN上的那些（可能因为我的c ++目前非常生疏，我犯了简单的错误）。这就是我对我有用的东西：

LPVOID lpOutBuffer = NULL;
DWORD dwSize = 0;

while (!HttpQueryInfo(hRequest, HTTP_QUERY_STATUS_CODE, (LPVOID)lpOutBuffer, &dwSize, NULL))    
{
    DWORD dwError = GetLastError();
    if (dwError == ERROR_INSUFFICIENT_BUFFER)
    {
        lpOutBuffer = new wchar_t[dwSize];  
    }
    else
    {
        fprintf(stderr, "HttpQueryInfo failed, error = %d (0x%x)\n",
            GetLastError(), GetLastError());
        break;
    }
}

wchar_t* outBuffer = (wchar_t*)lpOutBuffer;
std::wcout << L"Status_Code: " << outBuffer;

int status_code = _wtoi(outBuffer);

delete[] lpOutBuffer;

WinInet HttpQuery Info返回无效的状态代码

3 个答案: