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Author:       Fran鏾is PIETTE
Creation:     May 1996
Version:      2.66  UNTESTED VERSION
Object:       TFtpClient is a FTP client (RFC 959 implementation)
EMail:        http://users.swing.be/francois.piette  francois.piette@swing.be
              http://www.rtfm.be/fpiette             francois.piette@rtfm.be
              francois.piette@pophost.eunet.be
Support:      Use the mailing list twsocket@rtfm.be See website for details.
Legal issues: Copyright (C) 1997-2000 by Fran鏾is PIETTE
              Rue de Grady 24, 4053 Embourg, Belgium. Fax: +32-4-365.74.56
              <francois.piette@pophost.eunet.be>

              This software is provided 'as-is', without any express or
              implied warranty.  In no event will the author be held liable
              for any  damages arising from the use of this software.

              Permission is granted to anyone to use this software for any
              purpose, including commercial applications, and to alter it
              and redistribute it freely, subject to the following
              restrictions:

              1. The origin of this software must not be misrepresented,
                 you must not claim that you wrote the original software.
                 If you use this software in a product, an acknowledgment
                 in the product documentation would be appreciated but is
                 not required.

              2. Altered source versions must be plainly marked as such, and
                 must not be misrepresented as being the original software.

              3. This notice may not be removed or altered from any source
                 distribution.

              4. You must register this software by sending a picture postcard
                 to the author. Use a nice stamp and mention your name, street
                 address, EMail address and any comment you like to say.

Quick Reference:

Properties:
  HostName      - FTP server host name or IP address
  UserName      - User name for authentication on FTP server
  PassWord      - Passwor needed for user, can be blank
  HostDirName   - Directory as knwon of FTP server
  HostFileName  - File name as known on FTP server
  LocalFileName - Local file name (complete path)
  Binary        - Select binary or ascii file transfert (Need to call TypeSet
                  or TypeSetAsync to send it to FTP server).
  (There are other less used properties, see code below)

Methods:
  Open       - Open the connection with the FTP server
  User       - Send username
  Pass       - Send password
  Connect    - Open the connection, send username and password
  Quit       - Disconnect gracefully from FTP server
  Abort      - Disconnect (close connection) immediately
  Pwd        - Get current working directory
  Cwd        - Change Working Directory
  CDup       - Change to parent directory
  TypeSet    - Set type for file transfert (see Binary property)
  TypeBinary - Set to binary type transfert and call TypeSet
  TypeAscii  - Set to ascii type transfert and call TypeSet

  Put        - Upload a file
  Transmit   - Connect, Cwd, Upload a file & Quit

  Append     - Upload a file, appending to existing
  AppendFile - Connect, Cwd, Append a file & Quit

  Get        - Download a file
  Receive    - Connect, Cwd, Download a file & Quit

  RestGet    - Download a file, restarting from current local file size
  RestartGet - Connect, Cwd, Restart downloading a file & Quit

  RestPut    - Upload a file, restarting from ResumeAt property value
  RestartPut - Connect, Cwd, Restart uploading a file & Quit

  Dir        - Download a directory listing to a file
  Directory  - Connect, Cwd, Download a directory listing to a file & Quit

  Ls         - Download a file name listing to a file
  List       - Connect, Cwd, Download a file name listing to a file & Quit

  Mkd        - Create a directory on the server
  Mkdir      - Connect, Cwd, Create a directory on the server & Quit

  Ren        - Rename a file or directory on the server
  Rename     - Connect, Cwd, Rename a file or directory on the server & Quit

  Dele       - Delete a file on the server
  Delete     - Connect, Cwd, Delete a file on the server & Quit

  Rmd        - Remove a directoy from the server
  Rmdir      - Connect, Cwd, Remove a directoy from the server & Quit

  Syst       - Get system information from the server
  System     - Connect, Cwd, Get system information from the server & Quit

  Size       - Get file size
  FileSize   - Connect, Cwd, get file size & Quit

  Quote      - Send literal command (use LocalFileName as command to send)
  DoQuote    - Connect, Cwd, send literal command & Quit

  (There are two set of methods: Async and Sync. The Async are the prefered
   ones to build robust applications. Their name end with Async like GetAsync)
  (There are other less used methods, see code below)

How to use a Proxy or Firewall ?
   First of all, not all proxies or firewalls are the same. So have a look at
   product documentation. However, most products support a transparent proxy
   which doesn't require any special programming:
   1) Instead of connection to a remote FTP server, you connect to the proxy
   2) User name is replaced by user name, followed by '@' sign then followed
      by target remote FTP server host name.
   3) Password is usual remote FTP server password.
   4) Most require using Passive mode.
   Example: You want to connect to ftp.borland.com, using anonymous connection,
            company firewall/proxy is running on host named proxyserver.
            FtpCli1.HostName := 'proxyserver';
            FtpCli1.UserName := 'anonymous@ftp.borland.com';
            FtpCli1.Password := 'your.email@company';
            FtpCli1.Passive  := TRUE;

History:
Nov 04, 1996  Better error handling
              Property for timeout, defualt to 15 sec
Dec 03, 1996  Adapted display functionnality for Delphi 2
Dec 27, 1996  Added transmit functions
              Changed all procedure to function returning boolean status
Aug 13, 1997  Added multiline response support
              Added support for strange Microsoft PWS FTP behaviour
Sep 10, 1997  Added support for Dir and Ls commands
              Corrected bugs to enable correct use of separate commands
Oct 16, 1997  V2.07 Adapted for changes in TWSocket object
              Added FtpCliVersion constant
Nov 25, 1997  V2.08 Accept 250 as well as 226 for succesfull file transfert
              Suggested by fdragon@world-net.net
Nov 26, 1997  V2.09 don't display error message in the receive event when
              the socket is no more connected.
Nov 29, 1997  V2.10 added Mkd and Mkdir functions to create a directory.
              As suggested by Christian R鰏ner <christian.roesner@usa.net>
Dec 04, 1997  V2.11 Added Ren, Dele, Rmd functions
              As suggested by Frank Riemann <riemann@student.uni-kl.de>
              Changed Mkd and Mkdir functions to take HostFileName to
              specify the directory name. This is more consistent with the
              rest of the component usage.
Dec 29, 1997  V2.12 Added a TrimLeft function for Delphi 1
Dec 30, 1997  V2.13 Added Syst and System commands as suggested by
              Fire Dragon <fdragon@nosferatu.world-net.net>
              Added the LastResponse property
              Corrected a message ("Daniel Fazekas" <fdsoft@dns.gyor-ph.hu>)
Jan 10, 1998  V2.14 Accept response 150 and 125 for Get Submitted by Fire
              Dragon <fdragon@nosferatu.world-net.net>.
              Added a quick reference for most used properties and methods.
              Made TFtpCli a TComponent descendant.
              Added the Size, FileSize, Quote, DoQuote, RestartGet method.
              Made ControlSocket a readonly property (allow easy DNSLookup).
              Added a Port property.
Jan 25, 1998  V2.15
              Completely revised to make it asynchronous.
                This means that a new set of functions is born. They all have
                a name ending with Async. For example GetAsync. Asynchronous
                means that when you call the function, it returns almost
                immediately. The operation is done in the background.
                The asynchronous operation allows to make several request
                simultaneously WITHOUT using threads. Just use two or more
                TFtpClient and call each GetAsync (or other) method as those
                method returns almost instantly, all the request will be done
                in the background, generating the OnRequestDone when finished.
                Added a State property
                This allows to check for component work in the background.
                You can call methods only when State = ftpReady (except the
                Abort method which can be called at any time)
                The Asynchronous methods are the prefered ones.

              Added Pwd command
                Returns the current working directory on the server.

              Added CDup command
                Change to parrent directory on FTP server.

              Added DirResult property
                Parse the LastResponse property to return the directory.
                Do no always work when the server returns multi-line responses.
                (updated by Pwd, Cwd, CDup and Mkd commands).

              Changed function IsConnected to Connected, a read-only property.
                It's more object oriented.

              Replaced file I/O by stream I/O.
                It's the first step to allow Stream I/O outside of the component.

              New sample application (Delphi only now, CPP later).
                Every command has now a button to excercize it
                (async version only)

              The synchronous commands (old commands) are implemented by
                calling the asynchronous version and waiting.

              Multi-threaded property
                Tells the component how to wait for command completion.

              Removed the TWait component use.
                No need to have a TWait component.
Jan 31, 1998 V2.16 Accept response 150 and 125 for Put.
Feb 01, 1998 V2.17 Added intermediate message for OnRequestDone event
Feb 02, 1998 V2.18 Corrected a bug: all sync function returned always FALSE.
             Added User and Pass synchronous functions.
             Made PutAsync return ftpPutAsync in the OnrequestDone event.
Feb 04, 1998 V2.19 Added an OnCommand event to give a chance to the user to
             modify the commands to make some custom commands. Also added the
             OnResponse event to allow custom commands to get the response
             and alter it as necessary.
Feb 15, 1998 V2.20 Added a FindClose after the FindFirst in GetFileSize routine
             as pointed by "Daniel Fazekas" <fdsoft@dns.gyor-ph.hu>
Feb 21, 1998 V2.21 Enabled progress updated on put
Feb 22, 1998 V2.22 Accept result code 250 after Put command
             Implemented Append and AppendFile commands
Mar 07, 1998 V2.23 Made RequestType a R/O property
Mar 15, 1998 V2.24 Reordered PORT/REST/RETR
             Added a port command
             The ByteCount passed to OnProgress now take into account the
             restart byte offset.
             Renamed Display to TriggerDisplay and made it virtual
             Used TriggerDisplay everywhere.
             Modified the Timeout mechanism to reset the timeout each
             time the OnProgress event is called.
             Abort command call CancelDnsLookup approprietedly
Mar 27, 1998 V2.25 Adapted for C++Builder 3
Avr 01, 1998 V2.26 Made a valid LastResponse and ErrorMessage when DNS lookup
             failed. Added some compiler options.
Apr 10, 1998 V2.27 Added some ftpFctCwd in some highlevel functions.
             Suggested by Ray Andrews <ray_andrews@steeltoad.com>.
Apr 13, 1998 V2.28 Save error code when the data connection is closed to use
             it later to return the status for file transfert.
             Implemented passive mode, with help from Yaron Golan
             <yarong@shani.com>. A new property Passive enable this mode.
             Put do not work [yet] is passive mode.
Apr 14, 1998 V2.29 Made passive mode PUT work.
             Added ShareMode property (see TFileStream.Create on-line help)
             Made ResumeAt property.
Apr 15, 1998 V2.30 Added the OnReadyToTransmit event.
             Correctly handled error when local file not found.
             Checked if socket connected in SendCommand
Apr 22, 1998 V2.31 Corrected CDupAsync procedure (thanks to Eric
             Engler englere@swcp.com)
Apr 26, 1998 V2.32 Added TypeBinary and TypeAscii just to help a little bit.
May 01, 1998 V2.33 Added check for continuation lines in NextxPutAsync
May 05, 1998 V2.34 Added some more delay in WMFtpCloseData.
May 13, 1998 V2.35 In passive mode STOR or APPE, changed the sequence: now
             wait for connection established before sending the STOR or APPE
             command to FTP server.
May 19, 1998 V2.36 TransfertStats made virtual.
Jun 25, 1998 V2.37 Revised code for 'connection reset by peer' syndrome
Jul 09, 1998 V2.38 Adpted for Delphi 4
Jul 23, 1998 V2.39 Made ResumeAt property R/W
             Added code from Yaron Golan <yarong@shani.com> to fix PASV + REST
             and to add OnDisplayFile code to view a file on the fly.
Aug 04, 1998 V2.40 Frank Neuhaus <neuhaus@cpa.de> found a problem in Put command
             for some FTP server. See V240 in the comments.
Aug 12, 1998 V2.41 Added 200 to the valid CWD responses.
Aug 18, 1998 V2.42 Added code to accept continuation lines not beginning by
             a number and a dash. Thanks to Al Cantu <cantu@bfs.e-mail.com>
             for pointing this problem.
Sep 16, 1998 V2.43 Made Synchronize and WaitUntilReady virtual function in
             protected section.
Oct 01, 1998 V2.44 Checked for errors in TriggerRequestDone.
Nov 09, 1998 V2.45 Reverted V2.40 changes ! Thanks to Grant Walker
             <gw@enternet.com.au> for his help in testing.
             Made block size equal to 1514 to minimize packet fragmentation
             on ethernet.
Nov 22, 1998 V2.46 changed GetTickCount cast from Integer to LongInt because
             of overflows with Delphi 1. Suggested by Terry Byrne
             <terryb@fidlar.com>
Dec 22, 1998 V2.47 Corrected DisplayFile which forgot the last character.
             Thanks to max@zab1.chita.ru for the bug report.
             Handled exceptions while trying to connect data session.
             Replaced DisplayFlag by DysplayFileFlag.
Feb 14, 1999 V2.48 Indirectly call winsock functions using wsocket because
             wsocket provide runtime dynamic link instead of loadtime link.
             This allows a program to use FTP if it discover that winsock is
             installed and still run if winsock is not installed.
Mar 13, 1999 V2.49 Added FPutSessionOpened flag and combine it with
             FStorAnswerRcvd flag to synchronize start of data sending.
             Thanks to Frank Neuhaus for his clear analysis.
Mar 20, 1999 V2.50 Added Options property
Mar 23, 1999 V2.51 Corrected a bug introcuded in last version which truncated
             the first character of the second line of a multiline answer on
             some servers.
May 04, 1999 V2.52 Corrected an access violation in DataSocketGetDataAvailable.
             Thanks to Steve Plegge for pointing that bug.
May 21, 1999 V2.53 Added FRequestResult to ControlSocketDnsLookupDone. Thanks
             to Wu'hao <wvhao@263.net> for finding this bug.
Jul 17, 1999 V2.54 Added OnError event and DisplayFileMode property. Thanks to
             Pieter Snyman <pgws@iafrica.com> for his work.
             Accepted answer 200 for successful rename.
             Leho Kraav <macmanos@online.ee> found that some FTP server return
             this code.
             Cleared FByteCount from PortAsync as suggested by Simon Hoerup
             <cas@casdk.com> to help some progress indicator implementation.
Aug 04, 1999 V2.55 Corrected a bug with Delphi 1 where a buffer overflow may
             occurs when receiving commands longer than 254 bytes.
             Thanks to Craig Johnson <Craig_Johnson@emsinfo.com> for finding it.
             Also casted FTimeOut to LongInt for computation to prevent
             overflow with Delphi 1 for long timeout.
Aug 12, 1999 V2.56 HandleError was not correctly handling error message !
             thank to Kim M鴏g錼d Nielsen <kmn@bcview.com>
Aug 20, 1999 V2.57 Revised conditional compilation, adapted for BCB4, set
             compile options same as TWSocket.
             Added DnsResult property as suggested by Heedong Lim
             <hdlim@dcenlp.chungbuk.ac.kr>. This property is accessible from
             OnStateChange when state is ftpWaitingBanner.
             Added checks for FLocalStream being destroyed.
Sep 5, 1999  V2.58 Heedong Lim <hdlim@dcenlp.chungbuk.ac.kr> found a missing
             assignation to FRequestResult in ControlSocketSessionConnected.
Sep 11, 1999 V2.59 Added OnBgException. Thanks to William Sorensen
             <tzimisce@mwaccess.net> for suggesting it.
Oct 30, 1999 V2.60 Changed TargetPort and DataPort from integer to WORD so
             that Delphi 1 is able to handle port greater than 32K. Bug and
             and fix by Duncan Gold <Gold@esg-us.com>.
Nov 22, 1999 V2.61 Allow continuation lines in all responses.
Nov 24, 1999 V2.62 RestPut command by Alexander Burlakov <alex@helexis.com>
             Added RestartPut. Added ftpNoAutoResumeAt option.
Dec 26, 1999 V2.63 Corrected a bug in DoPutAppendAsync.
Jan 24, 1999 V2.64 Added LongInt cast to all GetTickCount.
Apr 01, 2000 V2.65 Removed any set of integer.
             Thanks to Grant Black <grant.black@smartmove.co.nz>,
             Davie <smatters@smatters.com> and
             Stephen Williams <SWilliams@fm.optus.net.au> for their work on
             this subject.