Status update regarding the partial upload issue when using FTPS connections:

I'm working on an update that will let you set the minimum and maximum TLS version when connecting to FTPS server. Lowering the maximum TLS version from 1.3 to 1.2 prevents the partial upload issue mentioned in this thread.

I reported the issue to the Curl project and I think they are aware of it, but I haven't gotten any reply from them. So, until this is fixed in curl, I'll add this workaround to Textastic.

The bigger problem is that someone might intercept your user name and password that is sent in clear text and would be able to do log in to your server with your credentials. 

There is an online tmTheme-Editor at https://tmtheme-editor.glitch.me

It also has a huge gallery of themes. You can edit and download themes and use them with Textastic. 

See https://www.textasticapp.com/v10/manual/customization/custom_syntax_themes_templates.html on how to add custom themes.

After you open a file, you can set the syntax definition to "Plain Text" in the file properties to disable syntax coloring for files with that file extension.

Yeah, that’s ok on an internal network, but not over the internet. 

Textastic internally uses libcurl for FTP connections. 

I could reproduce this issue on the command line with curl 8.7.1 on my Mac.

It seems to be a problem with TLS 1.3 when connecting to certain FTP servers. When I add "--tls-max 1.2" to the command to limit the TLS version to 1.2, the upload works fine.

An upload command like this results in a 0 byte file on the server:

curl --ssl-reqd ftp://<redacted>.kasserver.com/test/ -u <redacted> --upload-file test.html

While adding "--tls-max 1.2" works and uploads the file as expected:

curl --ssl-reqd ftp://<redacted>.kasserver.com/test/ -u <redacted> --upload-file test.html --tls-max 1.2

I've reported this issue to the curl project at https://github.com/curl/curl/issues/13556

For now I can only recommend to instead use an SSH connection in Textastic if you encounter this problem.

Thanks for the additional info. I received the log file from "Icke" and while the upload itself is reported as successful in the log file, it is followed by "450 Transfer aborted. Link to file server lost".

I hope I can find out more and will try to reproduce it.

Yes, we can continue by email - send it to support@textasticapp.com 

Ok, interesting, so that's probably a different issue.

Maybe there is a disk quota on your server that limits the size of files you can upload?

Please try to enable the "Debug Log" setting in the connection's settings screen. Tap on the (i) button on the right side of a connection to change its settings. This creates a log file when you try to connect to the server which might help to find out what's wrong.

We figured out that the "transferred a partial file" error happens when a file stored in iCloud Drive is edited on one device and then uploaded on another device. In this case, sometimes the wrong (outdated) size is used when uploading the file.

I don't know if that's the case for you as well.

I plan to implement a fix in a future update, but it requires a bigger restructuring of the code to use file coordination when uploading files.