用WinHttp 写一个POST和GET访问https://sellercentral.amazon.com.au/ap/signin 自定义函数。参数有访问方式，提交数据和访问头，并且返回响应内容和响应头，代码使用 Unicode 字符集

以下是使用WinHttp库编写的Unicode字符集的POST和GET请求函数的示例代码：

#include <windows.h>
#include <winhttp.h>

#pragma comment(lib, "winhttp.lib")

BOOL SendRequest(LPCWSTR lpwszUrl, LPCWSTR lpwszMethod, LPCWSTR lpwszData, LPCWSTR lpwszHeader, LPWSTR lpwszResponseHeader, DWORD dwHeaderLen, LPWSTR lpwszResponseData, DWORD dwDataLen)
{
    HINTERNET hSession = NULL, hConnect = NULL, hRequest = NULL;
    BOOL bResult = FALSE;

    // 打开一个HTTP会话
    hSession = WinHttpOpen(L"user-agent", WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
    if (!hSession)
    {
        goto Exit;
    }

    // 建立到目标服务器的连接
    hConnect = WinHttpConnect(hSession, lpwszUrl, INTERNET_DEFAULT_HTTPS_PORT, 0);
    if (!hConnect)
    {
        goto Exit;
    }

    // 创建一个请求句柄
    hRequest = WinHttpOpenRequest(hConnect, lpwszMethod, lpwszUrl, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_SECURE);
    if (!hRequest)
    {
        goto Exit;
    }

    // 添加请求头
    if (lpwszHeader)
    {
        if (!WinHttpAddRequestHeaders(hRequest, lpwszHeader, wcslen(lpwszHeader), WINHTTP_ADDREQ_FLAG_REPLACE))
        {
            goto Exit;
        }
    }

    // 发送请求
    if (!WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, (LPVOID)lpwszData, wcslen(lpwszData), wcslen(lpwszData) * sizeof(WCHAR), 0))
    {
        goto Exit;
    }

    // 接收响应头
    if (lpwszResponseHeader && dwHeaderLen > 0)
    {
        if (!WinHttpReceiveResponse(hRequest, NULL))
        {
            goto Exit;
        }

        if (!WinHttpQueryHeaders(hRequest, WINHTTP_QUERY_RAW_HEADERS_CRLF, WINHTTP_HEADER_NAME_BY_INDEX, lpwszResponseHeader, &dwHeaderLen, WINHTTP_NO_HEADER_INDEX))
        {
            goto Exit;
        }
    }

    // 接收响应数据
    if (lpwszResponseData && dwDataLen > 0)
    {
        DWORD dwTotalSize = 0;
        DWORD dwBytesRead = 0;
        LPBYTE lpBuffer = (LPBYTE)lpwszResponseData;

        while (WinHttpQueryDataAvailable(hRequest, &dwTotalSize) && dwTotalSize > 0)
        {
            if (dwTotalSize > dwDataLen - dwBytesRead)
            {
                goto Exit;
            }

            if (!WinHttpReadData(hRequest, lpBuffer + dwBytesRead, dwTotalSize, &dwBytesRead))
            {
                goto Exit;
            }

            dwBytesRead += dwTotalSize;
        }

        lpwszResponseData[dwBytesRead / sizeof(WCHAR)] = L'\0';
    }

    bResult = TRUE;

Exit:
    if (hRequest)
    {
        WinHttpCloseHandle(hRequest);
    }

    if (hConnect)
    {
        WinHttpCloseHandle(hConnect);
    }

    if (hSession)
    {
        WinHttpCloseHandle(hSession);
    }

    return bResult;
}

BOOL HttpGet(LPCWSTR lpwszUrl, LPCWSTR lpwszHeader, LPWSTR lpwszResponseHeader, DWORD dwHeaderLen, LPWSTR lpwszResponseData, DWORD dwDataLen)
{
    return SendRequest(lpwszUrl, L"GET", NULL, lpwszHeader, lpwszResponseHeader, dwHeaderLen, lpwszResponseData, dwDataLen);
}

BOOL HttpPost(LPCWSTR lpwszUrl, LPCWSTR lpwszData, LPCWSTR lpwszHeader, LPWSTR lpwszResponseHeader, DWORD dwHeaderLen, LPWSTR lpwszResponseData, DWORD dwDataLen)
{
    return SendRequest(lpwszUrl, L"POST", lpwszData, lpwszHeader, lpwszResponseHeader, dwHeaderLen, lpwszResponseData, dwDataLen);
}

示例用法：

int main()
{
    // GET请求
    wchar_t wszResponseHeader[1024] = { 0 };
    wchar_t wszResponseData[1024] = { 0 };
    HttpGet(L"https://sellercentral.amazon.com.au/ap/signin", NULL, wszResponseHeader, _countof(wszResponseHeader), wszResponseData, _countof(wszResponseData));
    wprintf(L"%s\n%s\n", wszResponseHeader, wszResponseData);

    // POST请求
    wchar_t wszData[] = L"param1=value1&param2=value2";
    HttpPost(L"https://sellercentral.amazon.com.au/ap/signin", wszData, L"Content-Type: application/x-www-form-urlencoded", wszResponseHeader, _countof(wszResponseHeader), wszResponseData, _countof(wszResponseData));
    wprintf(L"%s\n%s\n", wszResponseHeader, wszResponseData);

    return 0;
}