Reverse Proxy - Using Subdirectory

I cant use cname, therefore i would like to split my services into subdirectorys.

location /ha/  
    {
            proxy_pass              http://localhost:58123/;   #local IP of my HA server
            proxy_set_header   Host             $host;
            proxy_set_header   X-Real-IP        $remote_addr;
            proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
            proxy_set_header   Upgrade          $http_upgrade;
            proxy_set_header   Connection       "upgrade";
        }

When i do this i get the HA Logo, but in the developer console i see that he tries to load files from the main side.

e.g. instead /ha/frontend_latest/app.83207343.js i get /frontend_latest/app.83207343.js

Yes, because your /ha/ page lists /frontend_latest/app.83207343.js as a resource. You have three ways to solve this:

1. Tell your application that it should use relative paths, e.g. frontend_latest/app.83207343.js
2. Tell your application that it should use absolute, but correct paths, e.g. /ha/frontend_latest/app.83207343.js.
3. Use something like ngx_http_sub to do a rewrite on the fly.