c++ - GetLastError 在调用 WinHttpOpenRequest 后返回 6

Question

我不确定这是否是 msdn 知识不足。我有以下代码:

    #include "stdafx.h"
    #include <iostream>
    #include <string>
    #include <windows.h>
    #include <WinHttp.h>
    #include "myHTTP.h"
int main(){
    WinHTTP newHTTP("test", "test");
        bool myResult;

        newHTTP.httpConnect(L"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36",
        L"https://pages.awscloud.com/awsomedayonlineconference-reg.html",
        1,
        L"GET");

        newHTTP.httpAddHeader(L"Content-Type: application/x-www-form-urlencoded\r\n");
        newHTTP.httpSend();
        myResult = newHTTP.httpReceive();



        newHTTP.closeHandles();
 return 0;
}

我有一个类，正在执行以下行://打开请求 - 此时未连接

hRequest = WinHttpOpenRequest(hConnect, protocol.c_str(), NULL, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, 0);

if (!hRequest) {
    printf("error2: %d", GetLastError());
}

基本上，当我运行我的软件时，它会返回此处，因为调用 winhttpopenrequest 时 !hrequest 为空。我添加了 getlasterror 以查看这是为什么，但我得到的唯一输出是:

error2: 6

然后我阅读了 winhttp 的 msdn，我可以在这里看到函数返回的错误:https://msdn.microsoft.com/en-us/library/windows/desktop/aa384099(v=vs.85).aspx但是这个神秘的错误 6 对我来说毫无意义。

对于查看句柄为何无效的任何帮助？

完整类代码:

#pragma once
// WinHTTP wrapper for web protocol -- windows 8.1+
class WinHTTP {

private:
    std::string siteUsername, sitePassword;
    std::wstring UA, URL;
    bool bResult = false;
    DWORD dwSize = sizeof(DWORD); // used to handle reading data in bytes
    LPSTR pszOutBuffer; // used to Allocate space for the buffer.
    DWORD dwDownloaded = 0; // set to null if using asynchronously and use in callback function only
    HINTERNET hSession = NULL, hConnect = NULL, hRequest = NULL;

public:
    WinHTTP(std::string myuser = "", std::string mypass = "") {
        siteUsername = myuser;
        sitePassword = mypass;
    }

    // TODO: update to be able to add proxy details either here or before. do check if proxy has been detected in here and open/connect accordingly 
    void httpConnect(std::wstring userAgent, std::wstring myURL, int isHTTPS, std::wstring protocol) {

        UA = userAgent;
        URL = myURL;

        std::wstring acceptTypes = L"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8";

        int portToUse;
        if (isHTTPS == 1) {
            portToUse = 443;
        }
        else {
            portToUse = 80;
        }

        //initialize http and return session handle -- use c_str to convert wstring to LPCWSTR
        hSession = WinHttpOpen(UA.c_str(),
            WINHTTP_ACCESS_TYPE_NO_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);

        //make the connection request
        if (hSession) {
            hConnect = WinHttpConnect(hSession, URL.c_str(), portToUse, 0);
        }
        else {
            std::cout << "winhttpconnect error " << GetLastErrorAsString();
        }

        // open the request - not connected at this point
        hRequest = WinHttpOpenRequest(hConnect, protocol.c_str(), NULL, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, 0);

        if (!hRequest) {
            std::cout << "winhttpopenrequest error " << GetLastErrorAsString();
        }

    }

    std::string GetLastErrorAsString()
    {
        //Get the error message, if any.
        DWORD errorMessageID = ::GetLastError();
        if (errorMessageID == 0)
            return std::string(); //No error message has been recorded

        LPSTR messageBuffer = nullptr;
        size_t size = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
            NULL, errorMessageID, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPSTR)&messageBuffer, 0, NULL);

        std::string message(messageBuffer, size);

        //Free the buffer.
        LocalFree(messageBuffer);

        return message;
    }

    void httpAddHeader(std::wstring myheader) {

        if (hRequest) {
            bResult = WinHttpAddRequestHeaders(hRequest, myheader.c_str(), (ULONG)-1L, WINHTTP_ADDREQ_FLAG_ADD);
        }

    }

    bool httpSend() {
        if (hRequest) {
            bResult = WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0);
        }

        if (!bResult) {
            std::cout << "winhttpsendrequest error " << GetLastErrorAsString();
            return false;
        }
        else {
            return true;
        }
    }

    bool httpReceive() {

        if (bResult) {
            bResult = WinHttpReceiveResponse(hRequest, NULL);
        }

        if (bResult) {

            do
            {
                // Check for available data.
                dwSize = 0; //query data available looks for data in bytes
                if (!WinHttpQueryDataAvailable(hRequest, &dwSize))
                {
                    std::cout << "WinHttpQueryDataAvailable error " << GetLastErrorAsString();
                    break;
                }

                // No more available data.
                if (!dwSize)
                    return false;

                // Allocate space for the buffer. as dwSize now holds the size of the request
                pszOutBuffer = new char[dwSize + 1];  // just a way of freeing up memory 
                if (!pszOutBuffer)
                {
                    printf("Out of memory\n"); // couldnt allocate enough
                    return false;
                }

                ZeroMemory(pszOutBuffer, dwSize + 1); // fills a block of memory with 0s

                                                      // we know the expect size and have the pszoutbffer to write to - read the Data.
                if (!WinHttpReadData(hRequest, (LPVOID)pszOutBuffer,
                    dwSize, &dwDownloaded))
                {
                        std::cout << "WinHttpReadData error " << GetLastErrorAsString();
                    return false;
                }
                else
                {
                    printf("%s", pszOutBuffer);
                }

                // Free the memory allocated to the buffer.
                delete[] pszOutBuffer;
                return true;

                // This condition should never be reached since WinHttpQueryDataAvailable
                // reported that there are bits to read.
                if (!dwDownloaded)
                    return false;

            } while (dwSize > 0);

        }

        return false;

    }

    void closeHandles() {
        if (hRequest) WinHttpCloseHandle(hRequest);
        if (hConnect) WinHttpCloseHandle(hConnect);
        if (hSession) WinHttpCloseHandle(hSession);
    }

};

Answer 1

为什么会收到错误代码 6

错误代码 6 是 System Error Code ERROR_INVALID_HANDLE。

它告诉您传递给 WinHttpOpenRequest 的 hConnect 无效。

您只在调用 WinHttpOpen 之后检查 hSession，在调用 WinHttpOpenRequest 之后检查 hRequest。但是您永远不会检查 hConnect 是否有效。

您还需要检查 WinHttpConnect 返回的 hConnect，如果它无效，请在调用另一个 WINAPI 方法之前检查 GetLastError():

hSession = WinHttpOpen(UA.c_str(), WINHTTP_ACCESS_TYPE_NO_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);

if (hSession) {
    hConnect = WinHttpConnect(hSession, URL.c_str(), portToUse, 0);

    if (hConnect) {
        hRequest = WinHttpOpenRequest(hConnect, protocol.c_str(), NULL, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, 0);

        if (!hRequest) {
            std::cout << "WinHttpOpenRequest error " << GetLastErrorAsString();
        }
    }
    else {
        std::cout << "WinHttpConnect error " << GetLastErrorAsString();
    }
}
else {
    std::cout << "WinHttpOpen error " << GetLastErrorAsString();
}

为什么您调用 WinHttpConnect 失败

docs告诉我们 WinHttpConnect 需要一个服务器名称，而不是一个 URL:

pswzServerName [in]
Pointer to a null-terminated string that contains the host name of an HTTP server. Alternately, the string can contain the IP address of the site in ASCII, for example, 10.0.1.45.

但是您提供的字符串包含无效的 URL。您需要将"https://pages.awscloud.com/awsomedayonlineconference-reg.html"更改为"pages.awscloud.com"，然后提供路径页面作为 WinHttpOpenRequest 中的参数:

hRequest = WinHttpOpenRequest(hConnect, protocol.c_str(), path.c_str(), NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, 0);

其中 path 是一个包含 "/awsomedayonlineconference-reg.html" 的字符串。

为此，您可以将您的 URL 分成多个部分，或者更改您的 httpConnect 方法以获取服务器名和路径作为单独的参数。