WinHttpCrackUrl解析HTTPS时nScheme错误显示为Other(2)原因排查

运行以下C代码后，输出的协议类型并非HTTPS，而是Other(2)。执行环境为Windows 10（64位），代码以C14标准编译，请问该问题产生的原因是什么？

#include <windows.h>
#include <WinInet.h>
#include <winhttp.h>
#include <iostream>
#include <string>

#pragma comment(lib, "wininet.lib")
#pragma comment(lib, "Winhttp.lib")

int main() {
    std::wstring gitHubApiUrl = L"https://api.github.com";

    URL_COMPONENTSW urlComponents = {};
    urlComponents.dwStructSize = sizeof(URL_COMPONENTSW);

    // Buffers for host and path
    wchar_t hostName[256] = {};
    wchar_t urlPath[1024] = {};
    urlComponents.lpszHostName = hostName;
    urlComponents.dwHostNameLength = ARRAYSIZE(hostName);
    urlComponents.lpszUrlPath = urlPath;
    urlComponents.dwUrlPathLength = ARRAYSIZE(urlPath);

    // Call WinHttpCrackUrl
    if (!WinHttpCrackUrl(gitHubApiUrl.c_str(), static_cast<DWORD>(gitHubApiUrl.size()), 0, &urlComponents)) {
        std::wcerr << L"Failed to parse URL. Error: " << GetLastError() << std::endl;
        return 0;
    }

    // Output parsed components
    std::wcout << L"Scheme: ";
    switch (urlComponents.nScheme) {
    case INTERNET_SCHEME_HTTP: std::wcout << L"HTTP"; break;
    case INTERNET_SCHEME_HTTPS: std::wcout << L"HTTPS"; break;
    default: std::wcout << L"Other (" << urlComponents.nScheme << L")"; break;
    }
    std::wcout << std::endl;

    std::wcout << L"Host Name: " << urlComponents.lpszHostName << std::endl;
    std::wcout << L"URL Path: " << urlComponents.lpszUrlPath << std::endl;
    return 0;
}

• 核心原因：代码混用了WinINet和WinHTTP两个库的协议枚举常量。INTERNET_SCHEME_HTTP、INTERNET_SCHEME_HTTPS是WinINet库定义的枚举值，但WinHttpCrackUrl属于WinHTTP库，它返回的nScheme对应的是WinHTTP的枚举常量，两者数值不匹配：
  • WinINet中INTERNET_SCHEME_HTTPS的值为3
  • WinHTTP中HTTPS对应的枚举是WINHTTP_SCHEME_HTTPS，数值为2
• 修复方案：将switch语句中的枚举替换为WinHTTP库的对应常量：

  switch (urlComponents.nScheme) {
  case WINHTTP_SCHEME_HTTP: std::wcout << L"HTTP"; break;
  case WINHTTP_SCHEME_HTTPS: std::wcout << L"HTTPS"; break;
  default: std::wcout << L"Other (" << urlComponents.nScheme << L")"; break;
  }
  

• 注意事项：WinINet和WinHTTP是Windows平台独立的网络API，枚举、结构体与函数不能跨库混用，使用某一库的函数时必须配套使用该库的相关常量和类型。

内容的提问来源于stack exchange，提问作者MrHu