Как реализовать авторизацию через соцсети?

# Определяем главное зеркало
RewriteCond %{HTTP_HOST} ^www\.(.*) [NC]
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]

# Редирект с HTTP на HTTPS
RewriteCond %{HTTPS} off
RewriteCond %{HTTP:X_FORWARDED_PROTO} !^https$
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

RewriteCond %{HTTPS} off
RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule .* https://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]