location /CSS/websocket {
            proxy_pass http://css_ws_svr;
            proxy_set_header Host $host;
            proxy_set_header Remote_Addr $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
        }

        location /CSS {
            proxy_pass http://css_svr;
            proxy_set_header Host $host;
            proxy_set_header Remote_Addr $remote_addr;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            set $mscheme $scheme;
            if ($http_referer ~* ^https.*) {
                set $mscheme "https";
            }
            proxy_set_header X-Forwarded-Proto $mscheme;
        }

<Engine name="Catalina" defaultHost="localhost">

      
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <!-- This Realm uses the UserDatabase configured in the global JNDI
             resources under the key "UserDatabase".  Any edits
             that are performed against this UserDatabase are immediately
             available for use by the Realm.  -->
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">
        
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log." suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

        <Valve className="org.apache.catalina.valves.RemoteIpValve" remoteIpHeader="X-Forwarded-For" protocolHeader="X-Forwarded-Proto" protocolHeaderHttpsValue="https"/>

        <Context path="/CSS" docBase="/home/tomcat/app/cssv2"/>
      </Host>
    </Engine>

public void invoke(org.apache.catalina.connector.Request request, Response response)
 throws IOException, ServletException
{
......
if (protocolHeader != null) {
    String protocolHeaderValue = request.getHeader(protocolHeader);
    if (protocolHeaderValue != null)
    {

        if (protocolHeaderHttpsValue.equalsIgnoreCase(protocolHeaderValue)) {
            request.setSecure(true);
            
            request.getCoyoteRequest().scheme().setString("https");
        
            setPorts(request, httpsServerPort);
        } else {
            request.setSecure(false);
                
            request.getCoyoteRequest().scheme().setString("http");
                
            setPorts(request, httpServerPort);
        }
    }
}
......
}