Rewrite wildcard subdomain to the same name folder and get the subdomain name

Question

I want to do the next

subdomain.domain.com must load www.domain.com/app/index.php?var=subdomain subdomain.domain.com/index.php?var2=x must load www.domain.com/app/index.php?var=subdomain&var2=x

I have the next code that load the app folder but I also want to get the name of the subdomain but I don't know how to do it.

RewriteEngine on
RewriteCond %{HTTP_HOST} !^www\.example\.com$
RewriteCond %{HTTP_HOST} ^(\w+)\.example\.com$
RewriteCond %{REQUEST_URI}:%1 !^/([^/]+)/([^:]*):\1
RewriteRule ^(.*)$ /%1/$1 [QSA]

Thanks in advance.

Here is all my .htaccess

<Files .htaccess> 
deny from all 
</Files> 
#ModPagespeed off
# charset
AddCharset utf-8 .html
AddCharset utf-8 .js
AddCharset utf-8 .css
AddCharset utf-8 .php

# enable expirations
<IfModule mod_expires.c>
#ExpiresActive On
#ExpiresByType image/jpg "access plus 1 week"
#ExpiresByType image/jpeg "access plus 1 week"
#ExpiresByType image/gif "access plus 1 month"
#ExpiresByType image/png "access plus 1 month"
#ExpiresByType text/css "access plus 1 week"
#ExpiresByType application/pdf "access plus 1 month"
#ExpiresByType text/x-javascript "access plus 1 week"
#ExpiresByType image/x-icon "access plus 1 year"
#ExpiresDefault "access plus 1 week"
</IfModule>

<IfModule mod_deflate.c>
#AddOutputFilterByType DEFLATE text/plain
#AddOutputFilterByType DEFLATE text/html
#AddOutputFilterByType DEFLATE text/xml
#AddOutputFilterByType DEFLATE text/css
#AddOutputFilterByType DEFLATE text/js
#AddOutputFilterByType DEFLATE application/xml
#AddOutputFilterByType DEFLATE application/xhtml+xml
#AddOutputFilterByType DEFLATE application/rss+xml
#AddOutputFilterByType DEFLATE application/x-javascript

# LE INDICAMOS PARA QUE NAVEGADORES NO DEBE COMPRIMIR YA QUE PRESENTAN BUGS

#BrowserMatch ^Mozilla/4 gzip-only-text/html
#BrowserMatch ^Mozilla/4.0[678] no-gzip
#BrowserMatch bMSIE !no-gzip !gzip-only-text/html

</IfModule>

Options +FollowSymLinks
RewriteEngine on

#fuerza el acceso https
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

#Wildcards del dominio

RewriteCond %{HTTP_HOST} !=www.domain.com
RewriteCond %{HTTP_HOST} ^(\w+)\.domain\.com
RewriteRule .* /app/index.php?var=%1 [QSA]

#para error personalizado
ErrorDocument 403 "No disponible"

IndexIgnore .htaccess */.??* *~ *# */HEADER* */README* */_vti*
AddHandler application/x-httpd-php .html .htm .shtml .js
AddType application/x-httpd-php .html .htm .js

DirectoryIndex index.php index.html

Answer 1

This should add var variable with value of subdomain:

RewriteEngine on
RewriteCond %{HTTP_HOST} !=www.example.com
RewriteCond %{HTTP_HOST} ^(\w+)\.example\.com
RewriteRule .* /add/index.php?var=%1 [QSA]