In a quest to perform SFTP in Delphi next to FTP, I first researched what I was up against. A tiny voice in the back of my head said “SFTP is totally unlike FTP” and it was right: SFTP means SSH File Transfer Protocol, not Simple File Transfer Protocol nor FTP over SSH nor FTP over SSL aka FTPS – the latter is supported by Indy but the former isn’t.
I decided against SecureBlackBox (providing SFTPBlackbox) and IPWorks (SSH) as I tried both a while ago for S/MIME support and was disappointed about both the lack of features and documentation; in the end I went for wrapping OpenSSL for the “encrypt-then-sign” process and Indy for the SSMTP part. The merger of the SecureBlackBox and IPWorks made me even less happy.
The Chilkat alternative for SFTP isn’t too compelling either: ActiveX or DLL black-box without a lot of insight on how many people do use it.
So when I had to do SFTP and knew there are no free or open source SFTP components for Delphi available I opted for thinking outside the Delphi realm.
My basic idea was to embed either of these:
- Filezilla (as Filezilla on Windows is waaaay faster than WinSCP)
- WinSCP (a Windows SCP and SFTP client written in C++ Builder)
- PSFTP (the Putty SFTP client)
FileZilla
FileZilla internally uses FzSFtp.exe which is based on PSFTP code (but with some buffers making it faster than PSFTP or WinSCP).
According to the author, neither FzSFtp.exe nor FileZilla can be automated:
FileZilla cannot make any automated transfers at all. Neither FileZilla.exe nor fzsftp.exe (is for SFTP) can be used for any batch processing.
Source: run filezilla tzsftp from batch command line – FileZilla Forums
The WinSCP author commented in a similar fashion:
FileZilla does not have any command line arguments (nor any other way) that allow automatic transfer.
Source: windows – Command line option to download file in FileZilla – Stack Overflow
In addition, FileZilla is always a GUI program, so running it as a console app (which I’d prefer) would be impossible.
WinSCP
WinSCP can be automated in two ways:
- The WinSCP.exe command-line allows for a
/console and /script switch enabling scripting mode that you can use for Scripting and Task Automation :: WinSCP
- A wrapper around WinSCP.exe is availble as WinSCP .NET Assembly and COM Library :: WinSCP which requires both .NET to be installed and (from Delphi) calling through COM which I don’t like much
Since I already had good Delphi wrapping code round starting/waiting-for running processes, I’d opt for using WinSCP.com scripting.
There used to be wrapping code around: Use with Delphi :: Support Forum :: WinSCP
PSFTP
These Using PSFTP to transfer files securely links should get me going:
Chapter 6: Using PSFTP to transfer files securely
Practical examples:
Source locations
For my own reference, the open source locations:
Some semi-random Delphi SSL related postss
During the search above I found the below links that will be useful to me one day:
–jeroen
The Wiert Corner - irregular stream of stuff 