cljftp.clj

(ns cljftp
  (:require [clojure.java.io :as io])
  (:import [java.net URL]))

;; See also https://www.ietf.org/rfc/rfc1738.txt

;; a public FTP test server https://dlptest.com/ftp-test/
(def ftp-url "ftp://dlpuser:rNrKYTX9g7z3RgJRmxWuGHbeu@ftp.dlptest.com/")

(def file-name "test.txt")

(let [file-url  (URL. (str ftp-url file-name))
      ls-url    (URL. (str ftp-url ";type=d"))
      up-conn   (.openConnection file-url)
      down-conn (.openConnection file-url)
      list-conn (.openConnection ls-url)]

  ;; upload
  (with-open [os (.getOutputStream up-conn)]
    (io/copy "test file contents" os))

  ;; download
  (with-open [is (.getInputStream down-conn)]
    (io/copy is (io/file (str "/tmp/" file-name))))

  ;; remote directory listing
  (with-open [is (.getInputStream list-conn)]
    (println (slurp is))))

(slurp (str "/tmp/" file-name))