always run same script in location

[basti]

Hello,

i have a script where i can upload files. the uri is like

https://example.com/foo/bar.pl

the location looks like

location ~ ^/foo/(.*.\.pl|cgi)$ {
...
}

then a upload url is generatred

https://example.com/foo/u/f28c104/df3d-45ce/example.txt

the location for the uploaded files looks like

location ~ ^/foo/u/(.+?)(/.*)$ {
fastcgi_param  SCRIPT_FILENAME  /www/example.com/foo/dl.pl;
...
}

all is matching expact:
I need to download the file via dl.pl script. It looks like that the
script is not called at this location.
I only the the "default download" menu of the browser

Best regards

ps:
in apache there is  a SetHandler and an Action for doing that. how can i
do in ngx?