Setting Multiple Headers for HttpSendRequest

HttpSendRequest is most commonly used WinAPI from WinInet class for sending a http Requests in Win32 programming. 

Syntax is

    BOOL HttpSendRequest(

       _In_  HINTERNET hRequest,

       _In_  LPCTSTR lpszHeaders,

       _In_  DWORD dwHeadersLength,

       _In_  LPVOID lpOptional,

       _In_  DWORD dwOptionalLength

    );

Parameters :

 lpszHeaders [in] :   Headers for the request.

But in most of the requirements the request might have multiple headers, like:

        “Content-Type: application/x-www-form-

                      urlencoded”

       “Content-Type: application/xml”

or customized headers like :

       “sso_token :asff67afc4” 

       “staus_temp : proceed”

In these cases we can set multiple headers for a particular request by using WinAPI HttpAddRequestHeaders from WinInet class

     BOOL HttpAddRequestHeaders(

         _In_  HINTERNET hRequest,

         _In_  LPCTSTR lpszHeaders,

         _In_  DWORD dwHeadersLength,

         _In_  DWORD dwModifiers

       );

Parameters:

hRequest [in] :  A handle returned by a call to the HttpOpenRequest function.

lpszHeaders [in] :  Headers for the request

dwHeadersLength [in] : Length of the headers added in lpszHeaders  parameter

Example:

BOOL CWinInetMgr::LogIn(CString& userID, Cstring& strStToken, CString& strToken, CString& strError)

{

//Form the command to send the request to login

CString strCmd = _T(“/signIn/xml”);

CString strData;

strData.Format(_T(“<?xml version=\”1.0\” encoding=\”UTF-8\” 

          ?><username>%s</username>”),userID);

DWORD dwDataLen = strData.GetLength();

CString strCmdURL = m_strURL + strCmd;

m_hHttpFile = HttpOpenRequest( m_hConnect, dwDataLen ? 

          _T(“POST”) : _T(“GET”),strCmdURL, HTTP_VERSION, 

          NULL,NULL, m_dwHttpFlag, 0 );

if( NULL == m_hHttpFile ) {

strError = _T(“Error in Server Communication.”);

return FALSE;

}

// Setting the headers for Login command

CString strStHeader;

strStHeader.Format(_T(“token: %s”), strToken);

HttpAddRequestHeaders(m_hHttpFile, strStHeader, 

            strStHeader.GetLength(),NULL);

CString strTgtHeader;

strTgtHeader.Format(_T(“tgt_token: %s”), strStToken);

HttpAddRequestHeaders(m_hHttpFile, strTgtHeader, 

                               strTgtHeader.GetLength(), NULL);

CString strHeader = _T(“Content-Type: application/xml”);

BOOL bResult = FALSE;

bResult = SendHttpRequest( strData, strHeader, dwDataLen,    

            strError );

return bResult ;

}

References:

MSDN : HttpSendRequest

MSDN : HttpAddRequestHeaders