How do I edit files and dirs owned by _www, as ftp user when ftp user is added to the _www group?

Question

I have add an FTP user account to _www group. I expected to be able to edit a file as ftp user when the ftp user has been added to the _www group and the access perms are set to 0640. Do I need s for others? I haven't dealt with this before. I write php scripts that create, edit and delete files in web server document root directory. I have been setting the ownership of the directories containing the files create by script, and the script itself ownership to _www and perms set to 0666 (files)/0777(dirs) so I can intervene with ftp user. But that exposes access to other than the specific ftp user account.

This is the command I used (Macos High Sierra, logged into terminal with root account)

dseditgroup -o edit -a (ftp user account name) -t user _www

Thank you for time and attention

Answer 1

There were some issues I figured out: test file ownership was wheel, not _www. I had to set perms to 0660, not 0640... duh. So, I seem to have answered my own question

Thanks for time