Batch files...

[Smudger]

Remember them?

I have a need to use one, possibly.

The scenario is, we have a file which gets grabbed from an FTP site and put in a certain folder, which we need to decrypt using a Command Line script. Simple, you would think. But no, the file name changes every day, and need to be saved to another location with the same file name, minus the .crypt extension. Is there a way of querying the folder, obtaining the file name, then adding that file name into a command in order to decrypt the file, then move the decrypted file to one folder, and the original file to another?

[DanceswithUnix]

Give up on batch files now, will save time in the short run let alone the long run.

If you aren't a programmer, then write the script in Python. You should be able to use the curl library to talk to the ftp site to get a directory listing and grab the file to a temp directory, and then run the decrypter. As a plus side, the result should run on any operating system.

A quick google for "python curl ftp directory example" got me some code to start you off:

http://programming-tidbits.blogspot....directory.html


Edit: Personally I would use Ruby, but I think Python is easier to get started in and it is a useful skill.

[kalniel]

Which operating system?

[b0redom]

Well, given OP was asking about a batch file, I'm guessing Windows..... You could use powershell for this.

[Smudger]

It is indeed Windows.

Thanks, DwU, I'll take a look. The file is already extracted from FTP and dumped in a directory on the server, so that should save a few steps.

[DanceswithUnix]

After a quick play, it sounds like this would be a starting point. Feeds all *.crypt files in the current directory through a command called "somedecrypter" specifying the output file name by stripping the .crypt extension off the source file and plugging .out on the end.

I am not a Python programmer, but I can Google and hack something up
Tested on Linux.

#!/usr/bin/python

import glob, os

for fileName in glob.glob( '*.crypt' ):
    fileBase = os.path.splitext( fileName )[0]
    os.system( "somedecrypter --in " + fileName + " --out " + fileBase + ".out" )

[scaryjim]

... Simple, you would think. But no, the file name changes every day, and need to be saved to another location with the same file name, minus the .crypt extension. ...

That sounds like a recipe for something to go horribly wrong at some point. My first step would be to examine the entire process and see if it can be streamlined. Why does the filename change? What creates the file in the first place? Why does it have to be put in a particular folder? Why are you using a file format that has to be processed on the command line? etc.

At the minute it sounds like there's half a process in place, and you're adding another half a process, on ther assumption that gluing two half-processes together will give you a whole process. If the first half the process is out of your control completely then you'll have to work from the mid-point, but it's always worth examining the whole flow to see if any steps can be combined or, ideally, removed to streamline things...

EDIT: and, as b0redom mentioned, Powershell would be the Windows way to do this

[DanceswithUnix]

EDIT: and, as b0redom mentioned, Powershell would be the Windows way to do this

... locking you into doing with 8GB or ram and a 6 core Xeon what you should be able to accomplish easily on a Raspberry Pi

[Smudger]

That sounds like a recipe for something to go horribly wrong at some point. My first step would be to examine the entire process and see if it can be streamlined. Why does the filename change? What creates the file in the first place? Why does it have to be put in a particular folder? Why are you using a file format that has to be processed on the command line? etc.

At the minute it sounds like there's half a process in place, and you're adding another half a process, on ther assumption that gluing two half-processes together will give you a whole process. If the first half the process is out of your control completely then you'll have to work from the mid-point, but it's always worth examining the whole flow to see if any steps can be combined or, ideally, removed to streamline things...

EDIT: and, as b0redom mentioned, Powershell would be the Windows way to do this

The file comes from an external company, so we don;t have control over the filename, unfortunately, so we are indeed starting from the midpoint.

[Smudger]

Well, I did it in Powershell, and it works! Thanks all for the help, but now it fails when I run it as a scheduled task. Back to the drawing board.

[Millennium]

Please post the script out of interest? If it's not sensitive. I want to understand Powershell better.

[AGTDenton]

Well, I did it in Powershell, and it works! Thanks all for the help, but now it fails when I run it as a scheduled task. Back to the drawing board.

If possible consider running a Windows cron job over a Windows Scheduled Task... We've found it to be far more reliable.

[Smudger]

Please post the script out of interest? If it's not sensitive. I want to understand Powershell better.

Here you go, this was messing around to get it to work on my PC before transferring to live...

$name = Get-Item c:\Data\File\*.crypt | Select-Object -ExpandProperty Basename

.\openssl cms -decrypt -inkey "C:\Data\key.pem" -recip "C:\Data\cert.pem" -inform DER -in "c:\data\File\$name.crypt" -out "c:\data\File\$name"

Move-Item -Path 'c:\data\file\*.xml' -Destination '\\destserver\share\'

Remove-Item -Path 'c:\data\file\*.crypt'

[Smudger]

If possible consider running a Windows cron job over a Windows Scheduled Task... We've found it to be far more reliable.

Thanks for the advice, kind of thinking that it's working now, so we'll leave it using scheduled tasks, but will consider Cron if things go awry...

[DanceswithUnix]

Here you go, this was messing around to get it to work on my PC before transferring to live...

Note that the Python script I posted deals with more than one *.crypt file in the directory so if the job failed to run for some reason it should cope with a backlog of files.

Corner cases that shouldn't be possible often come back and bite you. What if there is one *.crypt file when the script starts running, but at the end a new one has turned up? Your powershell script will potentially delete an unprocessed file. Probably won't ever happen, but just a thought if the files start coming in more rapidly for some reason.

[Smudger]

Note that the Python script I posted deals with more than one *.crypt file in the directory so if the job failed to run for some reason it should cope with a backlog of files.

Corner cases that shouldn't be possible often come back and bite you. What if there is one *.crypt file when the script starts running, but at the end a new one has turned up? Your powershell script will potentially delete an unprocessed file. Probably won't ever happen, but just a thought if the files start coming in more rapidly for some reason.

Actually, the act of decrypting deletes the /crypt file anyway, so I've remove that line.

By all accounts, the delivery of this file is going to be sporadic, so it's a case of 'do what you can with the tools you've got, without spending too much time on it'... We'll look more deeply into it, I think, if it becomes a big thing...