Owner of the uploaded files Apache web server - php

Question

I'm having trouble handling the uploaded files on my web server.
First the file is uploaded to the temp server by user "daemon" then I copy the file to www/myapp/files folder by the "www-data" user. Everything works fine, I can read and write to the file, but when I try to delete the file I get an error. Because I'm trying to delete the file as www-data user (php script), but the owner of the file is daemon user.
My question is how can I fix this?
I'm not looking for any chmod or chown solutions, I prefer the solution to be through Apache or some other configuration files.
EDIT:
As requested file permissions:
-rw-r--r-- 1 daemon daemon 41638 Jan 19 08:59 FILE
The parent folder has 0777 permissions

Answer 1

You can add both users to one group like this:
usermod -a -G groupName userName
And then set up r\w permissions for that group

Answer 2

Avoid assumptions
Everything works fine, I can read and write to the file
This indicates that the file permissions themselves, and ownership, permit current usage. If as you say apache is running as www-data, it directly contradicts this:
As requested file permissions: -rw-r--r-- 1 daemon daemon 41638 Jan 19 08:59 FILE
Which would mean the file is not writable to www-data.
Because I'm trying to delete the file as www-data user (php script), but the owner of the file is daemon user.
The above statement is not true - ownership of a file does not affect who can delete it.
I'm not looking for any chmod or chown solutions, I prefer the solution to be through Apache or some other configuration files.
How about not ruling out solutions until you have a choice =)?
Deleting a file uses directory permissions, not file permissions
This is easily verifiable:
-> pwd
/tmp/so
-> whoami
www-data
-> ls -la
total 8
dr-xr-xr-x 2 www-data www-data 4096 Feb 18 14:34 .
drwxrwxrwt 8 root root 4096 Feb 18 14:36 ..
-rw-rw-r-- 1 www-data www-data 0 Feb 18 14:34 a-file
-> rm a-file
rm: cannot remove `a-file': Permission denied
note there is no write permissions to the folder /tmp/so - it's the only permission that matters. Here's another existing answer as a supportive reference.
So given that, the only solution is to ensure that the user attempting to delete a-file has write permission to the containing folder, which means for example:
# assuming daemon is the owner
chmod 7x7 www/myapp/files
^ www-data is not the owner or in the group daemon - so world perms apply
Or
chown www-data:www-data www/myapp/files
chmod 7x7 www/myapp/files
^ daemon needs write permission to the folder too
Or
chown www-data:sharedgroup www/myapp/files
chmod 77x www/myapp/files
^ daemon now reads the group perm, www-data is the owner
(With the upload process running as daemon:sharedgroup)
The above are one-time-only commands that need running; after which there is no need to modify the permissions for any file or folder to permit both www-data and daemon to manipulate files in www/myapp/files.