Rewrite subdirectory to https - apache

Question

I have been trying to rewrite a subdirectory from HTTP to HTTPS to no avail. I have looked at other posts and tried to implement the solutions:
RewriteEngine On
RewriteCond %{SERVER_PORT} 80
RewriteCond %{REQUEST_URI} subdirectory
RewriteRule ^(.*)$ https://www.exmaple.com/subdirectory/$1 [R,L]
and also
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^(subdirectory/.*)$ https://www.example.com/$1 [R=301,L]
and placing them either on the root directory .htaccess file or the Plesk's Apache and Ngnix settings. But whenever I typed
http://www.example.com/subdirectory/some.html
I will always get
https://www.example.com/subdirectory//subdirectory/some.html
which is of course 404 not found. Any assistance is appreciated.

Answer 1

To force HTTPs for just a single directory then what you can use is:
RewriteEngine On
RewriteCond %{HTTP:X-Forwarded-SSL} !on
RewriteCond %{REQUEST_URI} ^\/(subdirectory)
RewriteRule (.*) https://%{HTTP_HOST}/$1 [L,R=301]
RewriteCond %{HTTP:X-Forwarded-SSL} =on
RewriteCond %{REQUEST_URI} !^\/(subdirectory)
RewriteRule (.*) http://%{HTTP_HOST}/$1 [L,R=301]
What is the above doing? The first condition checks if HTTPs is not on, if not, then it will check for the directory /subdirectory/ if found it will force this directory and only this directory to HTTPs.
The second set of rules is basically the opposite, forcing everything to HTTP except for the directory /subdirectory/.
Make sure you clear your cache before testing this.