Lua redirects based on backend response

gistfile1.nginxconf

server {
    listen  7777;
    
    location / {
        root /tmp/www;
        index index.html;
        try_files $uri @lua;
    }
    
    location /api {
        rewrite /api/(.*)$ $1 break;
        proxy_pass http://localhost:7778;
    }
    
    location @lua {

            default_type 'text/plain';
 
            content_by_lua '
                local res = ngx.location.capture("/api/"..ngx.var.uri)
                if res.status == 200 then
                    ngx.redirect("http://google.com")
                end
                if res.status == 404 then
                    ngx.redirect("http://yandex.ru")
                end   
                ';
        }
    }