RewriteEngine On

RewriteCond %{HTTP:Upgrade} =websocket [NC]
RewriteRule ^(.*)$ ws://127.0.0.1:3001/$1 [P,QSA,L]

RewriteCond %{HTTP:Upgrade} !=websocket [NC]
RewriteRule ^(.*)$ http://127.0.0.1:3001/$1 [P,QSA,L]