Find open ports programmatically.

Overview

CL-USER> (find-port:port-open-p 5000)
T
CL-USER> (my-clack-app:start)
To load "clack-handler-hunchentoot":
  Load 1 ASDF system:
    clack-handler-hunchentoot
; Loading "clack-handler-hunchentoot"

Hunchentoot server is started.
Listening on localhost:5000.
T
CL-USER> (find-port:port-open-p 5000)
NIL
CL-USER> (find-port:find-port)
50123

Usage

The port-open-p function takes an integer and determines whether a port by that number is open.

The find-port function, by default takes no arguments, and returns an open port. Two keyword arguments, :min and :max, may be given to constrain the port range in which to search for ports.

By default, the range is from 40000 to 50000, since this function will probably be used e.g. to pick an open port for testing, rather than to pick a port to run a production server on.

License

Copyright (c) 2015 Fernando Borretti, 2025 - present lisp-maintainers org.

Licensed under the MIT License.