/*
 * $Id$
 */

/*
 * Harbour Project source code:
 *    uHTTPD (Micro HTTP server) session functions
 *
 * Copyright 2009 Francesco Saverio Giudice <info / at / fsgiudice.com>
 * www - http://harbour-project.org
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA (or visit the web site http://www.gnu.org/).
 *
 * As a special exception, the Harbour Project gives permission for
 * additional uses of the text contained in its release of Harbour.
 *
 * The exception is that, if you link the Harbour libraries with other
 * files to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the Harbour library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the Harbour
 * Project under the name Harbour.  If you copy code from other
 * Harbour Project or Free Software Foundation releases into a copy of
 * Harbour, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for Harbour, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.
 *
 */

#include "common.ch"
#include "hbclass.ch"
#include "fileio.ch"
#include "directry.ch"

#command IF <lexpr> THEN <*statement*>  =>;
         IF (<lexpr>) ; <statement> ; END

#command IF <lexpr> THEN <statement1> ELSE <statement2> =>;
         IF (<lexpr>) ; <statement1> ; ELSE ; <statement2> ; END

#xtranslate SetNewValueReturnOld( <p>, <v> ) => LOCAL xOld, xOld := <p>, IIF( <v> != NIL, <p> := <v>,  ), xOld
#xtranslate DEFAULT( <p>, <v> ) => ( <p> := IIF( <p> == NIL, <v>, <p> ) )


MEMVAR _COOKIE, _SESSION, _REQUEST, _SERVER

#define MY_CRCKEY "UhTTpK3y76"

FUNCTION uhttpd_SessionNew( cSessionName, cSessionPath )
RETURN uhttpd_Session():New( cSessionName, cSessionPath )

CLASS uhttpd_Session

   METHOD New()

   DESTRUCTOR DestroyObject()

   METHOD Start()
   METHOD IsRegistered()
   METHOD CacheExpire( nTimeInMinutes ) INLINE SetNewValueReturnOld( ::nCache_Expire, nTimeInMinutes )
   METHOD CacheLimiter()
   METHOD GetCookieParams()     INLINE { ::nCookie_LifeTime, ::cCookie_Path, ::cCookie_Domain, ::lCookie_Secure  }
   METHOD SetCookieParams()
   METHOD ID( cID )             INLINE SetNewValueReturnOld( ::cSID, cID )
   METHOD Name( cName )         INLINE SetNewValueReturnOld( ::cName, cName )
   METHOD RegenerateID()
   METHOD SavePath( cPath )     INLINE SetNewValueReturnOld( ::cSavePath, cPath )
   METHOD IsStarted()           INLINE ( ::nActiveSessions > 0 )
   METHOD UseOnlyCookies()      INLINE ::lUse_Only_Cookies
   METHOD UseTransSID()         INLINE ::lUse_Only_Cookies

   METHOD SaveCookie()
   METHOD GetSessionVars()
   METHOD GetVar( cVar )        INLINE uhttpd_HGetValue( _SESSION, cVar )
   METHOD SetVar( cVar, xValue ) INLINE _SESSION[ cVar ] := xValue

   METHOD SetSaveHandler()
   METHOD Open( cPath, cName )
   METHOD Close()
   METHOD Read( cID )
   METHOD Write( cID, cData )
   METHOD Destroy( cID )
   METHOD GC( nMaxLifeTime )

   METHOD SessionContainer( hHash )  INLINE SetNewValueReturnOld( _SESSION, hHash )
   METHOD Encode()              // INLINE HB_Serialize( _SESSION )
   METHOD Decode()

 HIDDEN:

   DATA oCookie
   DATA cSID
   DATA cSavePath               INIT "/tmp"
   DATA cName                   // INIT "SESSIONID"
   DATA lAuto_Start             INIT .F.       // .F. = no autostart
   DATA nGc_Probability         INIT 33        // Every 1/3 of checks i'll lunch Session GC
   DATA nGc_MaxLifeTime         INIT 1440      // seconds - Number of seconds after gc can delete a session
   // DATA cSerialize_Handler      INIT "HBHTMLLIB"
   DATA nCookie_LifeTime        INIT 3600 //0         // Number of seconds to keep cookie, 0 = until browser is closed
   DATA cCookie_Path            INIT "/"
   DATA cCookie_Domain
   DATA lCookie_Secure          INIT .F.
   DATA lUse_Cookies            INIT .T.       // .T. = Use cookies to store session id on client side
   DATA lUse_Only_Cookies       INIT .F.
   DATA cReferrer_Check                        // If is set check if referrer is equal to, if it isn't block
   // DATA cEntropy_File
   // DATA nEntropy_Lenght
   DATA cCache_Limiter          INIT "nocache" // Possible values are: none, nocache, private, private_no_expire, public
   DATA nCache_Expire           INIT 180       // in minutes, not checked if cCache_Limiter == none or nocache
   DATA lUse_Trans_SID          INIT .F.       // .F. = no SID appended to URL

   // Session Storage code blocks
   DATA bOpen                   //INIT {|cPath, cName| ::SessionOpen( cPath, cName ) }
   DATA bClose                  //INIT {|| ::SessionClose() }
   DATA bRead                   //INIT {|cID| ::SessionRead( cID ) }
   DATA bWrite                  //INIT {|cID, cData| ::SessionWrite( cID, cData ) }
   DATA bDestroy                //INIT {|cID| ::SessionDestroy( cID ) }
   DATA bGC                     //INIT {|nMaxLifeTime| ::SessionGC( nMaxLifeTime ) }
   DATA nFileRetry              INIT 10        // How many time try to open / write / delete file in case of error
   DATA nFileWait               INIT 500       // How many milliseconds have to wait before retry

   DATA nActiveSessions         INIT 0

   DATA lSessionActive          INIT .F.

   METHOD GenerateSID()
   METHOD CheckSID()
   METHOD SessionOpen()
   METHOD SessionClose()
   METHOD SessionRead()
   METHOD SessionWrite()
   METHOD SessionDestroy()
   METHOD SessionGC()

   METHOD SendCacheLimiter()

ENDCLASS

// ------------------------------ ***************************** -----------------------------------

METHOD New( cSessionName, cSessionPath ) CLASS uhttpd_Session

  //hb_ToOutDebug( "cSessionName = %s, cSessionPath = %s\n\r", cSessionName, cSessionPath )

  DEFAULT cSessionName TO "SESSION"
  DEFAULT cSessionPath TO ::cSavePath

  //::cSID := ::GenerateSID()

  // As default we will use FILES - this is FILE version
  ::bOpen     := {|cPath, cName| ::SessionOpen( cPath, cName ) }
  ::bClose    := {||    ::SessionClose() }
  ::bRead     := {|cID| ::SessionRead( cID ) }
  ::bWrite    := {|cID, cData| ::SessionWrite( cID, cData ) }
  ::bDestroy  := {|cID| ::SessionDestroy( cID ) }
  ::bGC       := {|nMaxLifeTime| ::SessionGC( nMaxLifeTime ) }

  /*
  // DBF version - we will store in a DBF - this only an example
  ::bOpen     := {|cPath, cName| DBF_Session_Open( cPath, cName ) }
  ::bClose    := {||    DBF_Session_Close() }
  ::bRead     := {|cID| DBF_Session_Read( cID ) }
  ::bWrite    := {|cID, cData| DBF_Session_Write( cID, cData ) }
  ::bDestroy  := {|cID| DBF_Session_Destroy( cID ) }
  ::bGC       := {|nMaxLifeTime| DBF_Session_GC( nMaxLifeTime ) }
  */

  ::cName     := cSessionName + "ID"
  ::cReferrer_Check := _SERVER[ "HTTP_REFERER" ]

  ::cSavePath := cSessionPath

  ::oCookie   := uhttpd_CookieNew( ::cCookie_Domain, ::cCookie_Path )

RETURN Self

METHOD Start( cSID ) CLASS uhttpd_Session
  LOCAL lSendCookie := .T.
  LOCAL lDefine_SID := .T.
  LOCAL xVal, nRand, nPos
  LOCAL hUrl

  IF cSID != NIL
     ::cSID := cSID
  ENDIF

  //hb_toOutDebug( "cSID = %s, ::cSID = %s\n\r", cSID, ::cSID )

  //TraceLog( "Active Sessions : " + hb_cStr( ::nActiveSessions ) )

  IF ::nActiveSessions != 0
     RETURN .F.
  ENDIF

  // Start checking ID from global vars
     IF ( nPos := hb_HPos( _REQUEST, ::cName ) ) > 0
        //::cSID := ::oCGI:h_Request[ ::cName ]
        ::cSID := hb_HValueAt( _REQUEST, nPos )
        IF HB_ISARRAY( ::cSID )
           ::cSID := ::cSID[ 1 ] // Get Only 1-st
        ENDIF
        lSendCookie := .F.
        lDefine_SID := .F.
        //::oCGI:ToLogFile( "::cSID = " + hb_cStr( ::cSID ), "/pointtoit/tmp/log.txt" )
     ENDIF

     IF !Empty( ::cSID ) .AND. !::CheckSID()
        // Check if the SID is NOT valid, someone altered it
        //::oCGI:ToLogFile( "::cSID = " + hb_cStr( ::cSID ) + " SID is NOT valid, someone altered it", "/pointtoit/tmp/log.txt" )
        ::cSID      := NIL   // invalidate current SID, i'll generate a new one
        lSendCookie := .T.
        lDefine_SID := .T.
      ENDIF

     IF !Empty( ::cSID ) .AND. !Empty( ::cReferrer_Check )
        // TODO: fix

        //oUrl := TUrl():New( ::cReferrer_Check )
        hUrl := uhttpd_SplitUrl( ::cReferrer_Check )

        //hb_ToOutDebug( "hUrl = %s\n\r", hb_ValToExp( hUrl ) )

        //IF !( oUrl:cServer == _SERVER[ "SERVER_NAME" ] )
        IF !( hUrl[ "HOST" ] == _SERVER[ "SERVER_NAME" ] )
           ::cSID      := NIL   // invalidate current SID, i'll generate a new one
           lSendCookie := .T.
           lDefine_SID := .T.
        ENDIF

        // // Check whether the current request was referred to by
        // // an external site which invalidates the previously found ID
        // $url = parse_url($GLOBALS['HTTP_REFERER']);
        // if (trim($url['host']) != $GLOBALS['SERVER_NAME']) {
        //    unset($session->id);
        //    $send_cookie = true;
        //    $define_sid = true;
        // }
      ENDIF

    // Do we have an existing session ID?
    IF Empty( ::cSID )
       // Create new session ID
       ::cSID := ::GenerateSID()
    ENDIF

    // Is use_cookies set to false?
    IF !::lUse_Cookies .AND. lSendCookie
       lDefine_SID := .T.
       lSendCookie := .F.
    ENDIF

    // Should we send a cookie?
    IF lSendCookie
       ::oCookie:SetCookie( ::cName, ::cSID, ::cCookie_Domain, ::cCookie_Path, uhttpd_DateToGMT(,,,::nCookie_LifeTime), ::lCookie_Secure )
    ENDIF

    // Should we define the SID?
    IF lDefine_SID
       cSID := ::cName + '=' + ::cSID
       _REQUEST[ ::cName ] := ::cSID
    ENDIF

    ::nActiveSessions++

    // Send caching headers

    // Start session
    IF !::Open(::cSavePath, ::cName )
       uhttpd_Die( 'ERROR: Failed to open session file' )
    ENDIF

    // Read session data
    IF !( ( xVal := ::Read( ::cSID  ) ) == NIL )
       //TraceLog( "Read session data - xVal", xVal )
       //::oCGI:ToLogFile( "xval = " + hb_cStr( xVal ), "/pointtoit/tmp/log.txt" )
       // Decode session data
       ::Decode( xVal )
       //::oCGI:ToLogFile( "decoded", "/pointtoit/tmp/log.txt" )
    ENDIF

    // Send HTTP cache headers
    ::SendCacheLimiter()

    // Check if we should clean up (call the garbage collection routines)
    //TraceLog( "::nGc_probability = " + hb_cStr( ::nGc_probability ) )
    IF ::nGc_probability > 0
       nRand := HB_RandomInt( 1, 100 )
       //TraceLog( "::nGc_probability - nRand = " + hb_cStr( nRand ) )
       IF nRand <= ::nGc_Probability
          ::GC( ::nGc_MaxLifeTime )
       ENDIF
    ENDIF

RETURN .T.

METHOD Destroy() CLASS uhttpd_Session

    IF ::nActiveSessions == 0
       RETURN .F.
    ENDIF

    // Destroy session
    IF !Eval( ::bDestroy, ::cSID )
       RETURN .F.
    ENDIF

RETURN .T.

METHOD Close() CLASS uhttpd_Session
  LOCAL cVal

    //TraceLog( "Session Close() - oCGI:h_Session", DumpValue( oCGI:h_Session ) )

    IF ::nActiveSessions == 0
      RETURN .F.
    ENDIF

    // Encode session
    cVal := ::Encode()

    // Save session
    IF !::Write( ::cSID, cVal )
       uhttpd_Die( 'Session could not be saved.' )
    ENDIF
    // Close session
    IF !Eval( ::bClose )
      uhttpd_Die('Session could not be closed.')
    ENDIF
    ::nActiveSessions--

RETURN .T.

METHOD Open( cPath, cName ) CLASS uhttpd_Session
RETURN Eval( ::bOpen, cPath, cName  )

METHOD Read( cID ) CLASS uhttpd_Session
RETURN Eval( ::bRead, cID  )

METHOD Write( cID, cData ) CLASS uhttpd_Session
RETURN Eval( ::bWrite, cID, cData )

METHOD GC( nMaxLifeTime ) CLASS uhttpd_Session
RETURN Eval( ::bGC, nMaxLifeTime )


METHOD IsRegistered() CLASS uhttpd_Session
  LOCAL lRegistered := .F.
RETURN lRegistered

METHOD CacheLimiter( cNewLimiter ) CLASS uhttpd_Session
  LOCAL cOldLimiter := ::cCache_Limiter
  IF cNewLimiter != NIL
     IF cNewLimiter $ "none/nocache/private/private_no_expire/public"
        ::cCache_Limiter := cNewLimiter
     ELSE
        uhttpd_Die( "ERROR: uhttpd_Session:CacheLimiter() - New Limiter is incorrect" )
     ENDIF
  ENDIF
RETURN cOldLimiter

METHOD SetCookieParams( nLifeTime, cPath, cDomain, lSecure  ) CLASS uhttpd_Session
  IF nLifeTime != NIL THEN ::nCookie_LifeTime := nLifeTime
  IF cPath     != NIL THEN ::cCookie_Path     := cPath
  IF cDomain   != NIL THEN ::cCookie_Domain   := cDomain
  IF lSecure   != NIL THEN ::lCookie_Secure   := lSecure
RETURN NIL

METHOD RegenerateID() CLASS uhttpd_Session
  ::cSID := ::GenerateSID()
  IF ::lUse_Cookies
     ::oCookie:SetCookie( ::cName, ::cSID, ::cCookie_Domain, ::cCookie_Path, uhttpd_DateToGMT(,,,::nCookie_LifeTime), ::lCookie_Secure )
  ENDIF
RETURN ::cSID

METHOD SaveCookie() CLASS uhttpd_Session
  LOCAL cExpires := uhttpd_DateToGMT( Date(), Time(),, ::nCookie_LifeTime )
  LOCAL cKey
  //oCGI:SetCookie( ::cName, ::cSID, ::cCookie_Domain, ::cCookie_Path, cExpires, ::lCookie_Secure )
  FOR EACH cKey IN _SESSION:Keys
      ::oCookie:SetCookie( ::cName + "_" + cKey, _SESSION[ cKey ], ::cCookie_Domain, ::cCookie_Path, cExpires, ::lCookie_Secure )
  NEXT
RETURN NIL

//METHOD ReadCookie()
//  oCGI:SetCookie( ::cName, ::cSID, ::cCookie_Domain, ::cCookie_Path, cExpires, ::lCookie_Secure )
//RETURN NIL

METHOD GetSessionVars( aHashVars, cFields, cSeparator ) CLASS uhttpd_Session
   LOCAL aNotSessionFlds := {}
   LOCAL aField, cField, aFields
   LOCAL cName, xValue
   LOCAL cSessPrefix := ::cName + "_"
   LOCAL cFieldsNotInSession := ""
   LOCAL cSessVarName
   DEFAULT cSeparator TO "&"

   aFields := hb_regexSplit( cSeparator, cFields )

   FOR EACH cField in aFields
      aField := hb_regexSplit( "=", cField, 2 )
      IF Len( aField ) != 2
         LOOP
      ENDIF

      cSessVarName := LTrim( aField[1] )
      //cName  := "_" + LTrim( aField[1] )   // ERROR ON VAR NAME WITH LEN 1. X
      //cName  := LTrim( aField[1] )   // ERROR ON VAR NAME WITH LEN 1. X

      //TraceLog( "SESSION: cSessVarName, cSessPrefix, Left( cSessVarName, Len( cSessPrefix ) )", ;
      //                    cSessVarName, cSessPrefix, Left( cSessVarName, Len( cSessPrefix ) ) )

      IF Left( cSessVarName, Len( cSessPrefix ) ) == cSessPrefix // IF Left part of var is equal to session prefixname i.e. "SESSION"

         cName  := Substr( cSessVarName, Len( cSessPrefix ) + 1 )
         xValue := uhttpd_UrlDecode( aField[2] )
         //TraceLog( "SESSION: cName, xValue", cName, xValue )

         //Tracelog( "cName, xValue", cName, xValue )

         // is it an array entry?
         IF Substr( cName, Len( cName ) - 1 ) == "[]"
            cName := Substr( cName, 1, Len( cName ) - 2 )
            //aHashVars[ cName ] := { xValue }

            aHashVars[ cName ] := { xValue }

            //aHashVars:Keys( cName )
            //__ObjSendMsg( aHashVars, "_" + cName, { xValue } )  // variant from Ron to handle 1 lenght name

         ELSE
            //aHashVars[ cName ] := xValue

            aHashVars[ cName ] := xValue

            //aHashVars:Keys( cName )
            //__ObjSendMsg( aHashVars, "_" + cName, xValue )  // variant from Ron to handle 1 lenght name
         ENDIF
         //Tracelog( "aHashVars, cName, xValue", DumpValue( aHashVars ), cName, xValue )
      ELSE
         aAdd( aNotSessionFlds, aField )
      ENDIF
   NEXT
   IF !Empty( aNotSessionFlds )
      FOR EACH aField IN aNotSessionFlds
          cFieldsNotInSession += aField[1] + "=" + aField[2] + "&"
      NEXT
      // Delete last & char
      cFieldsNotInSession := Left( cFieldsNotInSession, Len( cFieldsNotInSession ) - 1 )
   ENDIF

   //TraceLog( "SESSION: cFieldsNotInSession", cFieldsNotInSession )

RETURN cFieldsNotInSession



/*
 * SID = 25 random chars + 5 CRC chars
 */

METHOD GenerateSID( cCRCKey ) CLASS uhttpd_Session
   LOCAL cSID, nSIDCRC, cSIDCRC, n, cTemp
   LOCAL nLenSID     := 25
   LOCAL cBaseKeys   := "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
   LOCAL nLenKeys    := Len( cBaseKeys )
   LOCAL cRet
   LOCAL nRand, nKey := 0
   LOCAL nLenTemp
   //LOCAL a := 0

   //DEFAULT cCRCKey  TO "3InFoW4lL5" // Max Lenght must to be 10
   DEFAULT cCRCKey  TO MY_CRCKEY // Max Lenght must to be 10

   /* Let's generate the sequence */
   //cSID := Space( nLenSID )
   cSID := ""
   FOR n := 1 TO nLenSID - 5 // 5 = CRC Length
      nRand     := HB_RandomInt( 1, nLenKeys )
      //cSID[ n ] := cBaseKeys[ nRand ]
      cSID += SubStr( cBaseKeys, nRand, 1 )
      nKey += nRand
   NEXT

   nSIDCRC  := nKey * 51 // Max Value is 99603. a 5 chars number
   cTemp    := StrZero( nSIDCRC, 5 )
   cSIDCRC  := ""
   nLenTemp := Len( cTemp )
   FOR n := 1 TO nLenTemp
       //cSIDCRC += cCRCKey[ Val( cTemp[ n ] ) + 1 ]
       cSIDCRC += SubStr( cCRCKey, Val( SubStr( cTemp, n, 1 ) ) + 1, 1 )
       //::oCGI:ToLogFile( "cCRCKey = " + hb_cStr( SubStr( cCRCKey, Val( SubStr( cTemp, n, 1 ) ) + 1, 1 ) ), "/pointtoit/tmp/log.txt" )
   NEXT

   cRet := cSID + cSIDCRC
   //::oCGI:ToLogFile( "::GenerateSID() = " + hb_cStr( cSID ) + " " + hb_cStr( cSIDCRC ), "/pointtoit/tmp/log.txt" )

   //TraceLog( "Generate SID: cRet, cSID, nSIDCRC, cTemp, cSIDCRC, nKey, a", cRet, cSID, nSIDCRC, cTemp, cSIDCRC, nKey, a )

RETURN cRet

METHOD CheckSID( cSID, cCRCKey ) CLASS uhttpd_Session
   LOCAL nSIDCRC, cSIDCRC, n, cTemp
   LOCAL nLenSID     := 25
   LOCAL cBaseKeys   := "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
   LOCAL nRand, nKey := 0
   LOCAL nLenTemp
   LOCAL lOk
   //LOCAL a := 0

   DEFAULT ::cSID  TO ::RegenerateID()
   DEFAULT cSID    TO ::cSID
   DEFAULT cCRCKey  TO MY_CRCKEY // Max Lenght must to be 10

   //hb_toOutDebug( "cSID = %s, ::cSID = %s\n\r", hb_valtoexp( cSID ), hb_valtoexp( ::cSID ) )

   IF !Empty( cSID )

      /* Calculate the key */
      FOR n := 1 TO nLenSID - 5 // 5 = CRC Length
         //nRand     := At( cSID[ n ], cBaseKeys )
         nRand     := At( SubStr( cSID, n, 1 ), cBaseKeys )
         nKey += nRand
      NEXT

      // Recalculate the CRC
      nSIDCRC  := nKey * 51 // Max Value is 99603. a 5 chars number
      cTemp    := StrZero( nSIDCRC, 5 )
      cSIDCRC  := ""
      nLenTemp := Len( cTemp )
      FOR n := 1 TO nLenTemp
          //cSIDCRC += cCRCKey[ Val( cTemp[ n ] ) + 1 ]
          cSIDCRC += SubStr( cCRCKey, Val( SubStr( cTemp, n, 1 ) ) + 1, 1 )
      NEXT

      lOk := ( Right( cSID, 5 ) == cSIDCRC )

      //TraceLog( "Check SID: cRet, cSID, nSIDCRC, cTemp, cSIDCRC, nKey, a", cRet, cSID, nSIDCRC, cTemp, cSIDCRC, nKey, a )
      //::oCGI:ToLogFile( "::CheckSID() = " + hb_cStr( cSID ) + " " + hb_cStr( cSIDCRC ), "/pointtoit/tmp/log.txt" )
   ENDIF

RETURN lOk

// -------------------------------*************************-----------------------------------------

METHOD SetSaveHandler( bOpen, bClose, bRead, bWrite, bDestroy, bGC ) CLASS uhttpd_Session
   IF bOpen    != NIL THEN ::bOpen    := bOpen
   IF bClose   != NIL THEN ::bClose   := bClose
   IF bRead    != NIL THEN ::bRead    := bRead
   IF bWrite   != NIL THEN ::bWrite   := bWrite
   IF bDestroy != NIL THEN ::bDestroy := bDestroy
   IF bGC      != NIL THEN ::bGC      := bGC
RETURN NIL

METHOD SessionOpen( cPath, cName ) CLASS uhttpd_Session
  //TraceLog( "SessionOpen() - cName", cName )
  IF cPath != NIL THEN ::cSavePath := cPath
  IF cName != NIL THEN ::cName     := cName

RETURN .T.

METHOD SessionClose() CLASS uhttpd_Session
  //TraceLog( "SessionClose()" )
  // Nothing to do
RETURN .T.

METHOD SessionRead( cID ) CLASS uhttpd_Session
  LOCAL nH
  LOCAL cFile
  LOCAL nFileSize
  LOCAL cBuffer
  LOCAL nRetry  := 0

  DEFAULT cID TO ::cSID
  cFile := ::cSavePath + hb_ps() + ::cName + "_" + cID
  //TraceLog( "SessionRead: cFile", cFile )
  IF File( cFile )
     DO WHILE nRetry++ <= ::nFileRetry
        IF ( nH := FOpen( cFile, FO_READ + FO_DENYWRITE ) ) != -1

           nRetry := 0
           DO WHILE nRetry++ <= ::nFileRetry
              nFileSize := FSeek( nH, 0, FS_END )
              FSeek( nH, 0, FS_SET )
              cBuffer := Space( nFileSize )
              IF ( FRead( nH, @cBuffer,  nFileSize ) ) != nFileSize
                 //uhttpd_Die( "ERROR: On reading session file : " + cFile + ", File error : " + hb_cStr( FError() ) )
                 hb_idleSleep( ::nFileWait / 1000 )
                 LOOP
              ENDIF
              FClose( nH )
              EXIT
           ENDDO

        ELSE
           //uhttpd_Die( "ERROR: On opening session file : " + cFile + ", File error : " + hb_cStr( FError() ) )
           hb_idleSleep( ::nFileWait / 1000 )
           LOOP
        ENDIF
        EXIT
     ENDDO
  ENDIF
  //TraceLog( "SessionRead() - cID, cFile, nFileSize, cBuffer", cID, cFile, nFileSize, cBuffer )
RETURN cBuffer

METHOD SessionWrite( cID, cData ) CLASS uhttpd_Session
  LOCAL nH
  LOCAL cFile
  LOCAL nFileSize
  LOCAL lOk := .F.
  LOCAL nRetry  := 0

  //TraceLog( "SessionWrite() - cID, cData", cID, cData )
  DEFAULT cID   TO ::cSID
  DEFAULT cData TO ""

  nFileSize := Len( cData )

  cFile := ::cSavePath + hb_ps() + ::cName + "_" + cID
  //TraceLog( "SessionWrite() - cFile", cFile )
  IF nFileSize > 0
     DO WHILE nRetry++ <= ::nFileRetry
        IF ( nH := hb_FCreate( cFile, FC_NORMAL, FO_READWRITE + FO_DENYWRITE ) ) != -1
           IF ( FWrite( nH, @cData,  nFileSize ) ) != nFileSize
              uhttpd_Die( "ERROR: On writing session file : " + cFile + ", File error : " + hb_cStr( FError() ) )
           ELSE
              lOk := .T.
           ENDIF
           FClose( nH )
        ELSE
           //uhttpd_Die( "ERROR: On WRITING session file. I can not create session file : " + cFile + ", File error : " + hb_cStr( FError() ) )
           hb_idleSleep( ::nFileWait / 1000 )
           LOOP
        ENDIF
        EXIT
     ENDDO
  ELSE
     // If session data is empty, I will delete the file if exist
     //IF File( cFile )
     //   FErase( cFile )
     //ENDIF
     // Return that all is ok
     lOk := .T.
  ENDIF
RETURN lOk

METHOD SessionDestroy( cID ) CLASS uhttpd_Session
  LOCAL cFile
  LOCAL lOk
  LOCAL nRetry  := 0

  //TraceLog( "SessionDestroy() - cID", cID )
  DEFAULT cID TO ::cSID

  _SESSION := { => }
  ::oCookie:DeleteCookie( ::cName )

  //TraceLog( "SessionDestroy() - cID, oCGI:h_Session", cID, DumpValue( oCGI:h_Session ) )
  cFile := ::cSavePath + hb_ps() + ::cName + "_" + cID

  lOk := .F.
  DO WHILE nRetry++ <= ::nFileRetry
     IF ( lOk := ( FErase( cFile ) == 0 ) )
        EXIT
     ELSE
        hb_idleSleep( ::nFileWait / 1000 )
        LOOP
     ENDIF
  ENDDO

  //IF !( lOk := ( FErase( cFile ) == 0 ) )
  //   uhttpd_Die( "ERROR: On deleting session file : " + cFile + ", File error : " + hb_cStr( FError() ) )
  //ELSE

  IF lOk
     //TraceLog( "SessionDestroy() - Sessione Eliminata - File " + cFile )
     // Genero un nuovo SID
     ::RegenerateID()
  ENDIF
RETURN lOk

METHOD SessionGC( nMaxLifeTime ) CLASS uhttpd_Session
  //TraceLog( "SessionGC() - nMaxLifeTime", nMaxLifeTime )
  //STATIC nStartTime
  LOCAL nSecs
  LOCAL aDir, aFile

  DEFAULT nMaxLifeTime TO ::nGc_MaxLifeTime
  aDir := Directory( ::cSavePath + hb_ps() + ::cName + "_*.*" )

  FOR EACH aFile IN aDir
      nSecs := TimeDiffAsSeconds( aFile[ F_DATE ], Date(), aFile[ F_TIME ], Time() )
      //TraceLog( "GC: aFile[ F_NAME ], aFile[ F_DATE ], Date(), aFile[ F_TIME ], Time(), nSecs, nMaxLifeTime", ;
      //               aFile[ F_NAME ], aFile[ F_DATE ], Date(), aFile[ F_TIME ], Time(), nSecs, nMaxLifeTime )
      IF nSecs > nMaxLifeTime
         // No error checking here, because if I cannot delete file now I will find it again on next loop
         FErase( ::cSavePath + hb_ps() + aFile[ F_NAME ] )
      ENDIF
  NEXT

RETURN .T.

STATIC FUNCTION TimeDiffAsSeconds( dDateStart, dDateEnd, cTimeStart, cTimeEnd )
  LOCAL aRetVal

  DEFAULT dDateEnd     TO DATE()
  DEFAULT cTimeEnd     TO TIME()

  aRetVal := FT_ELAPSED( dDateStart, dDateEnd, cTimeStart, cTimeEnd )

RETURN aRetVal[ 4, 2 ]


// Nanforum ELAPSED
STATIC FUNCTION FT_ELAPSED(dStart, dEnd, cTimeStart, cTimeEnd)
  LOCAL nTotalSec, nCtr, nConstant, nTemp, aRetVal[4,2]

  IF ! ( VALTYPE(dStart) $ 'DC' )
     dStart := DATE()
  ELSEIF VALTYPE(dStart) == 'C'
     cTimeStart := dStart
     dStart     := DATE()
  ENDIF

  IF ! ( VALTYPE(dEnd) $ 'DC' )
     dEnd := DATE()
  ELSEIF VALTYPE(dEnd) == 'C'
     cTimeEnd := dEnd
     dEnd     := DATE()
  ENDIF

  IF( VALTYPE(cTimeStart) != 'C', cTimeStart := '00:00:00', )
  IF( VALTYPE(cTimeEnd)   != 'C', cTimeEnd   := '00:00:00', )

  nTotalSec  := (dEnd - dStart) * 86400                              + ;
                VAL(cTimeEnd)   *  3600                              + ;
                VAL(SUBSTR(cTimeEnd,AT(':', cTimeEnd)+1,2)) * 60     + ;
                IF(RAT(':', cTimeEnd) == AT(':', cTimeEnd), 0,         ;
                VAL(SUBSTR(cTimeEnd,RAT(':', cTimeEnd)+1)))          - ;
                VAL(cTimeStart) * 3600                               - ;
                VAL(SUBSTR(cTimeStart,AT(':', cTimeStart)+1,2)) * 60 - ;
                IF(RAT(':', cTimeStart) == AT(':', cTimeStart), 0,     ;
                VAL(SUBSTR(cTimeStart,RAT(':', cTimeStart)+1)))

  nTemp := nTotalSec

  FOR nCtr := 1 to 4
     nConstant := IF(nCtr == 1, 86400, IF(nCtr == 2, 3600, IF( nCtr == 3, 60, 1)))
     aRetVal[nCtr,1] := INT(nTemp/nConstant)
     aRetval[nCtr,2] := nTotalSec / nConstant
     nTemp -= aRetVal[nCtr,1] * nConstant
  NEXT

RETURN aRetVal


// -------------------------------*************************-----------------------------------------

METHOD Encode() CLASS uhttpd_Session
  LOCAL aSerial := {}
  LOCAL cKey, xVal

  IF Type( "_SESSION" ) == "H"

     FOR EACH cKey IN _SESSION:Keys
         xVal := _SESSION[ cKey ]
         IF xVal != NIL THEN aAdd( aSerial, { cKey, xVal } )
     NEXT

  ENDIF

RETURN IIF( !Empty( aSerial ), HB_Serialize( aSerial ), NIL )

METHOD Decode( cData ) CLASS uhttpd_Session
  LOCAL lOk := .T.
  LOCAL cSerial := cData
  LOCAL xVal, aElem
  //LOCAL cKey

  //TraceLog( "Decode - cSerial", cSerial )
  //::oCGI:ToLogFile( "Decode - cSerial = " + hb_cStr( cSerial ), "/pointtoit/tmp/log.txt" )

  DO WHILE ( xVal := HB_Deserialize( @cSerial ) ) != NIL
     //TraceLog( "Decode - xVal", DumpValue( xVal ) )
     //::oCGI:ToLogFile( "Decode - xVal = " + hb_cStr( xVal ) + ", ValType( xVal ) = " + ValType( xVal ), "/pointtoit/tmp/log.txt" )

     SWITCH ValType( xVal )
        //CASE 'O'
        //   //TraceLog( "Decode - xVal - Object", xVal )
        //   IF xVal:classname == "TASSOCIATIVEARRAY"
        //      //TraceLog( "Decode - xVal - Object - TAssociativeArray - Keys", xVal:Keys )
        //      FOR EACH cKey IN xVal:Keys
        //          //TraceLog( "Decode TassociativeArray - cKey, xVal:SendKey( cKey )", cKey, xVal:SendKey( cKey ) )
        //          _SESSION:SendKey( cKey, xVal:SendKey( cKey ) )
        //      NEXT
        //   ENDIF
        //   EXIT

        CASE 'A'  // Le variabili sono conservate come array { VarName, Value }
           //TraceLog( "Decode - xVal - Array", xVal )
           //::oCGI:ToLogFile( "Decode - xVal - Array = " + hb_cStr( xVal ) + ", Len = " + hb_cStr( Len( xVal ) ), "/pointtoit/tmp/log.txt" )
           FOR EACH aElem IN xVal
               //::oCGI:ToLogFile( "Decode - aElem = " + hb_cStr( hb_valtoexp( aElem ) ), "/pointtoit/tmp/log.txt" )
               _SESSION[ aElem[1] ] := aElem[2]
           NEXT
           EXIT

        OTHERWISE
           uhttpd_Die( "ERROR: On deserializing session data" )
           lOk := .F.
           EXIT
     ENDSWITCH
  ENDDO

RETURN lOk

METHOD SendCacheLimiter() CLASS uhttpd_Session
  LOCAL dDate
  DO CASE
     CASE ::cCache_Limiter == 'nocache'
          //uhttpd_SetHeader( 'Expires', 'Thu, 19 Nov 1981 08:52:00 GMT' )
          uhttpd_SetHeader( 'Expires', uhttpd_DateToGMT( ,,-1, ) )
          uhttpd_SetHeader( 'Cache-Control', 'no-cache' )
          //uhttpd_SetHeader("Cache-Control", "no-store, no-cache, must-revalidate")  // HTTP/1.1
          //uhttpd_SetHeader("Cache-Control", "post-check=0, pre-check=0", .F. )
          uhttpd_SetHeader( 'Pragma', 'no-cache' )
     CASE ::cCache_Limiter == 'private'
          uhttpd_SetHeader( 'Expires', 'Thu, 19 Nov 1981 08:52:00 GMT' )
          uhttpd_SetHeader( 'Cache-Control', 'private, max-age=' + LTrim( Str( ::nCache_Expire * 60 ) ) )
          IF hb_FGetDateTime( hb_argv(0), @dDate )
             uhttpd_SetHeader( 'Last-Modified', uhttpd_DateToGMT( dDate ) )
          ENDIF
     CASE ::cCache_Limiter == 'public'
          uhttpd_SetHeader( 'Expires', uhttpd_DateToGMT( ,,, ::nCache_Expire * 60 ) )
          uhttpd_SetHeader( 'Cache-Control', 'public, max-age=' + LTrim( Str( ::nCache_Expire * 60 ) ) )
          IF hb_FGetDateTime( hb_argv(0), @dDate )
             uhttpd_SetHeader( 'Last-Modified', uhttpd_DateToGMT( dDate ) )
          ENDIF
     OTHERWISE
          uhttpd_Die( "ERROR: Caching method " + ::cCache_Limiter + " not implemented." )
  ENDCASE
  //__OutDebug( "Header cache '" + ::cCache_Limiter + "' inviato" )
RETURN NIL

PROCEDURE DestroyObject() CLASS uhttpd_Session
   ::Close()
   //::oCGI:ToLogFile( "Session destroyed" )
   //::oCGI := NIL
RETURN