在VC中WININET如何使用HTTP的POST方法

SUMMARY
To properly simulate a Form submission using WinInet, you need to send a header that indicates the proper Content-Type. For Forms, the proper Content-Type header is: Content-Type: application/x-www-form-urlencoded

MORE INFORMATION
In many cases, the server does not respond appropriately if a Content-Type is not specified. For example, the Active Server Pages component of IIS 3.0 actually checks this header specifically for 'application/x-www-form- urlencoded' before adding form variables to the "Request.Form" object. This MIME/Content-Type indicates that the data of the request is a list of URL- encoded form variables. URL-encoding means that space character (ASCII 32) is encoded as ' ', special character such '!' encoded in hexadecemal form as '!'.

Here is a snippet of code that uses the MFC WinInet classes to simulate a Form POST request:

CString strHeaders = _T("Content-Type: application/x-www-form-urlencoded");
// URL-encoded form variables -
// name = "John Doe", userid = "hithere", other = "P&Q"
CString strFormData = _T("name=John Doe&userid=hithere&other=P&Q");
CInternetSession session;
CHttpConnection* pConnection = session.GetHttpConnection(_T("ServerNameHere"));
CHttpFile* pFile = pConnection->OpenRequest(CHttpConnection::HTTP_VERB_POST,_T("FormActionHere"));
BOOL result = pFile->SendRequest(strHeaders,(LPVOID)(LPCTSTR)strFormData, strFormData.GetLength());

Without MFC, the same code translates to straight SDK calls as follows:

static 

TCHAR hdrs[] = _T("Content-Type: application/x-www-form-urlencoded");

static 

TCHAR frmdata[] = _T("name=John Doe&userid=hithere&other=P&Q");
statuc TCHAR accept[] = _T("Accept: */*");
    
// for clarity, error-checking has been removed
HINTERNET hSession = InternetOpen("MyAgent",INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
HINTERNET hConnect = InternetConnect(hSession, _T("ServerNameHere"),
                                     INTERNET_DEFAULT_HTTP_PORT,
                                     NULL,
                                     NULL,
                                     INTERNET_SERVICE_HTTP,
                                     0,
                                     1);
HINTERNET hRequest = HttpOpenRequest(hConnect, 
                                     "POST",
                                     _T("FormActionHere"), 
                                     NULL, 
                                     NULL, 
                                     accept, 
                                     0, 
                                     1);
HttpSendRequest(hRequest, 
                hdrs, 
                strlen(hdrs), 
                frmdata, 
                strlen(frmdata));

// close any valid internet-handles

我这里有一段程序，用来在一个对话框里显示出一次http request的原始信息，不过使用Inet API做的，希望能有帮助。

void CHTTPRequestDlg::OnButtonRequest() 
{
    UpdateData(TRUE);   
    HINTERNET hInternet = InternetOpen("Mozilla/4.0 (compatible; MSIE 5.0; Windows NT 5.0)", 
                                        INTERNET_OPEN_TYPE_DIRECT,
                                        NULL,
                                        NULL,
                                        NULL);   
    HINTERNET hSession = InternetConnect(hInternet,
                                        m_strHost,   
                                        m_nPort,
                                        "username",
                                        "password",   
                                        INTERNET_SERVICE_HTTP,
                                        0,
                                        0);   
    char* szAccept[] = {"*/*",NULL};
    CString strVerb;
    m_comboVerb.GetWindowText(strVerb);   
    HINTERNET hRequest = HttpOpenRequest(hSession,
                                        strVerb,
                                        m_strObject,
                                        NULL,
                                        NULL,
                                        (LPCSTR*)szAccept,
                                        0,
                                        0);   
    struct   
    {   
        char* Language;   
        char* Encoding;   
        char* ContentType;   
    }Headers = {"Accept-Language:zh-cn\r\n",
                "Accept-Encoding:gzip,deflate\r\n",   
                "Content-Type:application/x-www-form-urlencoded\r\n"};
    
    if(m_bLanguage)   
    {
        HttpAddRequestHeaders(hRequest,
                                Headers.Language, 
                                -1,
                                HTTP_ADDREQ_FLAG_ADD|HTTP_ADDREQ_FLAG_REPLACE);   
    }
    if(m_bEncoding)   
    {
        HttpAddRequestHeaders(hRequest,
                                Headers.Encoding, 
                                -1,
                                HTTP_ADDREQ_FLAG_ADD|HTTP_ADDREQ_FLAG_REPLACE);   
    }
    if(m_bContentType)   
    {
        HttpAddRequestHeaders(hRequest,
                                Headers.ContentType,
                                -1,
                                HTTP_ADDREQ_FLAG_ADD|HTTP_ADDREQ_FLAG_REPLACE);   
    }
    LPCSTR lpAddHeader = NULL;
    LPCSTR lpContent = NULL;   

    if(m_strHeaders.GetLength())   
    {   
        if(m_strHeaders.Right(2) != "\r\n")   
        {
            m_strHeaders+="\r\n";   
        }
        lpAddHeader = (LPCSTR)m_strHeaders;   
    }   
    if(m_strContent.GetLength() && (strVerb == "POST" || strVerb == "PUT"))   
    {
        lpContent = (LPCSTR)m_strContent;   
    }
    HttpSendRequest(hRequest,
                    lpAddHeader,
                    -1,
                    (LPVOID)lpContent,
                    m_strContent.GetLength());   
    
    m_editContentGot.SetSel(0,-1);   
    m_editContentGot.ReplaceSel("");   
    
    LPSTR lpszData;        //buffer for the data   
    DWORD dwSize;        //size of the data available   
    DWORD dwDownloaded; //size of the downloaded data   
    
    //Set the cursor to an hourglass.   
    SetCursor(LoadCursor(NULL,IDC_WAIT));   
    
    // This loop handles reading the data.   
    while(1)   
    {   
        // The call to InternetQueryDataAvailable determines the amount of 
        // data available to download.   
        if (!InternetQueryDataAvailable(hRequest,&dwSize,0,0))   
        {   
            SetCursor(LoadCursor(NULL,IDC_ARROW));   
            break;   
        }   
        else   
        {     
            // Allocates a buffer of the size returned by InternetQueryDataAvailable   
            lpszData = new char[dwSize+1];   
            
            // Reads the data from the HINTERNET handle.   
            if(!InternetReadFile(hRequest,(LPVOID)lpszData,dwSize,&dwDownloaded))   
            {   
                delete[] lpszData;   
                break;   
            }   
            else   
            {   
                // Adds a null terminator to the end of the data buffer   
                lpszData[dwDownloaded]='\0';   
                
                int nLen = m_editContentGot.GetWindowTextLength();   
                m_editContentGot.SetSel(nLen-1, nLen-1);   
                m_editContentGot.ReplaceSel(lpszData);   
                
                // Delete the two buffers   
                delete[] lpszData;   
                
                // Check the size of the remaining data.   If it is zero, break.   
                if (dwDownloaded == 0)   
                {
                    break;   
                }
            }
        }   
    }   
    
    // Close the HINTERNET handle   
    InternetCloseHandle(hRequest);   
    InternetCloseHandle(hSession);   
    InternetCloseHandle(hInternet);   
    
    // Set the cursor back to an arrow   
    SetCursor(LoadCursor(NULL,IDC_ARROW));   
}

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使用MFC示例如下:
首先设置m_strRequest请求字符串 eg."name=aaa&pass=bbb";
m_strServerName 服务器名称或者IP eg."www.yahoo.com"
m_strObjectName 请求文件位置 eg. "pub/aaa.asp"
请求的结果存放在m_strHtml中

void func()
{   
    CInternetSession m_InetSession("session");
    CHttpConnection *pServer = NULL;
    CHttpFile* pFile = NULL;   
    try
    {   
        INTERNET_PORT nPort;
        nPort=80;
        pServer = m_InetSession.GetHttpConnection(m_strServerName, nPort);
        pFile = pServer->OpenRequest(CHttpConnection::HTTP_VERB_POST,m_strObjectName);
        char szHeaders[100];
        strcpy(szHeaders,"Accept: text*/*\r\nContent-Type: application/x-www-form-urlencoded");
        pFile->AddRequestHeaders(szHeaders);
        
        pFile->SendRequestEx(m_strRequest.GetLength());   
        pFile->WriteString(m_strRequest);//重要-->m_Request 中有"name=aaa&name2=BBB&"
        pFile->EndRequest();
        DWORD dwRet;
        pFile->QueryInfoStatusCode(dwRet);
        CString str;
        
        m_Mutex.Lock();
        m_strHtml="";
        char szBuff[1024];

        if (dwRet == HTTP_STATUS_OK)
        {
            UINT nRead;   
            while ((nRead = pFile->Read(szBuff,1023))>0)   
            {   
                m_strHtml += CString(szBuff,nRead);   
            }
        }
        m_Mutex.Unlock();   
        
        delete pFile;   
        delete pServer;   
    }   
    catch (CInternetException* e)
    {   
        CString s;   
        s.Format("Internet Exception\r\nm_dwError%u,m_dwContextError%u",e->m_dwError,e->m_dwContext);   
        AfxMessageBox(s);   
        //catch errors from WinInet   
    }   
}

1、获得WebBrowser Control的DWebBrowserEvents2::DocumentComplete事件
2、在DWebBrowserEvents2::DocumentComplete事件中根据IWebBrowser2::Document获得IHTMLDocument2
3、IHTMLDocument2::forms得到IHTMLElementCollection
4、在IHTMLElementCollection中根据name、tagName、ID得到指定的IHTMLElement
5、从IHTMLElement得到IHTMLFormElement
6、执行IHTMLFormElement::submit