.htaccess - How to deny all directories except one?

Question

I have this structure:

 /folder/public/
 /folder/text.txt
 /folder/app/
 (etc...)

I want visitors to access to /public/ except everything else.

Answer 1

You can use this rule in site root .htaccess:

RewriteEngine On

# block everything except /folder/public/
RewriteRule !^folder/public/ - [F,NC]