CODEWITHSUNDEEP
c#.netfilesftpfile-transfer
sabisabi
sabisabi

Reputation: 1511

Check sftp file transfer completed?

We have here a windows server and one day we will get via sftp some text files in a folder. I dont have more information, but maybe this is enough. Now I should write a function that is moving these files into another folder. Well that should not be that hard, I thought... but now I realized that Im able to move a file before its finished. So I was searching for some solutions and Im really confused.

My solution would be to check the file and the processes around it. Because if the file is not finished yet, there is a copy-process and I can check this process. To make this easy, I just have to try to lock the file and if there is no another process, well then the file is ready for move?

using (File.Open("myFile", FileMode.Open, FileAccess.Read, FileShare.None)) 
{ /*rdy!*/ }

But now I see that people are writing something about checksum test or to test the filesize and if the filesize is not changing then the file is ready. Is this stuff not a little bit complicated? Please tell me that my solution could work also... Im not able to test it with any server to server sftp stuff. I just know that if I copy a file to another folder (via explorer) this is working. Does this work via sftp transfer as well? Any ideas? Thank you

Upvotes: 2

Views: 4880

Answers (2)

Ed Trembicki-Guy
Ed Trembicki-Guy

Reputation: 11

Another option is to have the sender put a control file after the data file. For example, put uploadfile-20220714.txt, then put uploadfile-20220714.ctl. The control file can contain file information such as the name and size of the data file. This option requires the sender to modify their process, but it shouldn't require too much effort.

Upvotes: 0

Thorsten Dittmar
Thorsten Dittmar

Reputation: 56727

File-size checks are dangerous - what if the upload is suspended and later resumed? How much time should go by until you accept the current file size as the final file size? => Not a good solution.

I'd go for the locking, however, this only works if the process that writes the file also opens the file in a way so that it is locked exclusively. If the process doesn't do that, you'll be stuck with your problem again.

Another solution would be to upload the files with temporary names, like ".sftptmp". And to have the uploader rename it after it is done. That way you can be sure the file has been uploaded - just ignore all files that end with ".sftptmp". This, however, assumes that you actually have control over the process of uploading files.

Upvotes: 3

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