[Freeswitch-users] launch an external program in dialplan

Hi there, I need inside a dialplan, to launch an external program, and to take the return of this program to use it in the dialplan. I think a LUA script can do it? If anyone has an example script, I'm interested. Or is another technique better? Launching an external program at each call can be very resource-intensive, maybe make a request on a specific web service port, or something else? the idea is to add the user's name in the from. (but this name changes depending on the external context, it must be calculated, I cannot make a simple database query) someone has already done it I guess I'm not the first to have this need... Thank you all... Gilles