htaccess to prevent root access to folders with no index.htm(l)/php - with a redirect - scripts can still be accessed

Question

What I have in each directory.

<Files *>
    Deny From All
</Files>

I would like to put an htaccess file in my root main directory that does this:

1- prevents root access to any folder.

2- Redirects the user to one url should he try to access any root.

3- Still allow scripts to run and write in those directories publicly.

I also want to make sure that if an index,htm(l)/ or ,php file exists, that is loaded normally.

I seem to be struggling in figuring this out.

Thanks in advance for rewriting this beginner in the right direction.

Answer 1

# No root access without index.*
Options -Indexes
DirectoryIndex index.php index.html index.htm

# Rewrite
RewriteEngine On
RewriteBase /

# Existing file
RewriteCond %{REQUEST_FILENAME} !-f
# Existing directory
RewriteCond %{REQUEST_FILENAME} !-d
# Symbolic link
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule ^ your-default-file.html [L]    

I’m not sure about your point 3. The webserver doesn’t know if an user agent is a script or a browser.