TJFTP
- A Visual C++ FTP Client
(Published at
CodeProject.com and
CodeGuru.com, Nov 2005)
Download demo project - (.zip) 173 Kb
Download source, for VS .NET 2003
- (.zip) 66 Kb
Download source, for Visual Studio
5
- (.zip) 66 Kb
Download User's Manual - (.zip, Word
document) 71 Kb
Download Project Write-up - (.zip,
Word document) 110 Kb
Introduction
Ever wonder what goes on behind the scenes when you use an FTP client? What
actually happens at the socket level, and what the program does in the
background?
TJFTP is a
CFormView-derived FTP (File Transfer Protocol)
application written in Visual C++ 4
and 5. VC++ had no
CInternetSession,
CFtpConnection,
CAsyncSocket,
CSocket, or
Socket
MFC
classes back then, so I wrote in the FTP functionality from scratch, creating
custom sockets classes to handle the control and data connections. Then I
coded the GUI to manipulate directory and file creation, deletion, and transfer
once I had the connection, and to stay updated with the progress of
operations.
Background
Back in 1996 I was writing some apps for a computer engineering master's
final project. I decided to
see if I could write a fully functional FTP app that would incorporate
some nice GUI stuff. Features I wanted included; a Connection
dialog box to allow users to create and save connection profiles in the
Registry; List Controls with in-place label editing and column sorting
on both sides of the connection; double-clicking to initiate file
transfers; selecting and transferring multiple files; and a progress
indicator to show the user the status of file transfers. Having
never programmed before, I bought VS 4 and, after mastering the "Hello
World" beginner's app we all write, got to work.
Early in 2005 I stumbled on the source code to TJFTP, which I thought I'd
lost. I considered recompiling it in VC++ .NET for fun, but I was sure it
would blow up, after 8 years and several iterations of Visual C++, Windows, and
WinSock. However, it compiled under .NET with no errors,
and ran fine on Windows XP.
Some of the Custom Classes
CWinsock
(csock.cpp): Controls the Winsock subsystem with
Startup(), Shutdown() and ErrorBox() functions.
CStreamSocket
(csock.cpp): Creates and destroys control and
data sockets. Creates and accepts connections, and sends and receives
data. Handles Winsock events, including asynchronous read and write
events to prevent blocking (i.e freezing until the Winsock calls were
done).
CFtpConnect
(ftpconnect.
cpp): A CDialog-based class that opens a dialog box for the
user to input connection info into when the the app starts and when the
"Connect" button is pushed. Stores connection "profiles" in the Registry so
users save their information from session-to-session.
CMainView
(mainview.cpp): The real "guts" of the
program. Handles all the GUI stuff for the main interface, including list
controls, pushbuttons, and the progress indicator. Processes Winsock
messages, creates sockets from
CStreamSocket, listens to connections, and
accepts connections and data. Allows user to select Binary or ASCII transfer,
or let the program auto detect the transfer mode.
Points of Interest
DOCUMENTATION: Because I was writing this app as part of a master's
thesis, the project had to be documented to software engineering
standards. Each subroutine has a complete header comment, and there
are comment lines sprinkled liberally throughout the code explaining what's
going on. In addition, I wrote a
user's manual, and I've also extracted the
portion
of my thesis that deals with TJFTP. It has detailed information
on each subroutine, and program flow diagrams, such as the main flow diagram
below (dotted lines are asynchronous Winsock callbacks) :
TJFTP Main Program Flow Diagram
The flow diagrams show how convoluted the whole process is,
and the difficulty in keeping track of everything going on. Code snippets
aren't really appropriate for this article, because there is so much going
on. I suggest you grab the flow diagrams, open the code in VS, and
dig around.
FUNCTIONALITY: I've tested the recompiled program
on Win XP SP1 and
SP2, uploading files to my FTP server, then downloading them back to my local
machine with both TJFTP and a commercial FTP client. Then I
checked the file to see if it matched the original file.
The largest file I tested was 300 Mb. As you can
see from the screenshot above, I also logged on to a commercial server
that allows anonymous connections and successfully downloaded files. TJFTP
seems very stable, it hasn't crashed on me yet.
Caveat
This program is provided for
informational
use only. Although I have used it without file corruption or
other problems, I make no claims to this effect...do not use it as you would a
commercial FTP app. Also, TJFTP is NOT secure...passwords are are sent in plain
text and are NOT encrypted.
History
- Written Nov '96 - Feb '97 in Visual C++ 4 and 5
- Recompiled March, '05 in Visual Studio .NET 2003
Back
Updated
July 12, 2006