FTP: Add MDTM command to support timestamps

[Isaac]

I just purchased FolderSync and I am having some problems in two-sync mode to keep a document folder in sync between my tablet and my cell phone. I also tried using MD5 sums, but somehow I still ran into issues with FolderSync reuploading or redownloading files to and from the FTP server, files that were already present on either of the two devices. I also tested enabling the FTP legacy mode, with no luck either. I quicky ran through the support forum and discovered a few other users describing similar issues.

Anyway, I would like to be able to test the timestamp feature, but my FTP server (vsftpd) doesn't support the MFTM command (which FolderSync attempts to use according to my log files). It only supports MDTM. I understand that according to specs, it is _recommended_ to use MFMT since MDTM was not intended to be used for modifying an object's last modification time. Yet, strictly speaking, it wouldn't be forbidden to use MDTM, and it's the case that many FTP servers (including vsftpd, all Synology NAS devices, etc.) only support MDTM for changing a file's timestamp. 

Could you consider adding an option (or test it automaticall) to use MDTM when MFMT command is not supported by the server, so that I (and many others) can make FTP backups based on timestamp? I noticed you already query a FTP server's capabilities using FEAT, so it should be easy to decide when MDTM and when to MFMT is supported.

Cheers,

Isaac

[Jimar Suurmeijer]

Thanks Isaac, that explains a lot to me.

 

Just bought Foldersync to automatically backup (1 way sync from local to remote) some sdcard folders on my Android device to my Synology NAS FTP server and I just couldn't figure out why it would re-upload all files when I start a sync.

This explains why it does: Foldersync can't set the modified timestamp so when a file takes more time to upload than the allowed difference in modified timestamps it will just re-upload the file... This means it will upload multiple GB's (rom backup, pics, music) everytime I start a sync.

 

For now i could try to overcome the reuploading by setting the allowed difference in timestamps to more than the time it takes the biggest file to upload... That will be something like 15 minutes!

 

I really hope a new version of FolderSync will be able to use MDTM command :)

[Isaac]

I hope this, too. For now I discontinued using FolderSync because syncing with my FTP is my only option, and since I cannot change the FTP daemon, I am stuck as long as FolderSync doesn't support either way of modifying the timestamp.

[Support User]

The currently released version of Foldersync attempts to use the MTDM command if the server reports it is supported (and it reports MFMT is not supported) for ftp non-legacy mode.

[Jimar Suurmeijer]

That would mean Foldersync already uses MDTM while uploading files with non legacy ftp to my Synology Nas.

If that's the case then it might be something else is going wrong. I have tried every setting available but cannot get sync via ftp to work properly, whatever the settings I use it just keeps uploading all the files to ftp, whether the files changed or not.

After changing to SMB it worked directly, now it only uploads the changed files to my Nas.
This is a very nice app when it works, especially the Tasker plugins are cool.
But I do miss my simple off site (I travel a lot) ftp backup.

[Support User]

The thing is, even if MDTM not working, retransfers should not happen.

If you want to sync from off site, you use WebDAV with the synology. Its a little bit faster also, at least on my Synology.