A small library to generate boundaries for multipart/form-data and so on.

generate_boundary.clj

(ns generate-boundary)

(defn- char-range
  "Returns a lazy seq of characters between `start` and `end`.
  Unlike clojure.core/range, `end` is included in the results.
  e.g. (= \9 (last (char-range \0 \9)))"
  [start end]
  (map char (range (int start) (inc (int end)))))

(def ^:dynamic *characters*
  "Seq of characters used for suffix in boundaries."
  (concat (char-range \0 \9) (char-range \a \z) (char-range \A \Z) "-_"))

(defn generate-boundary
  "Generate a boundary followed by `n` (40 by default) characters in *characters* randomly.
  See also: http://www.ietf.org/rfc/rfc2388.txt"
  ([]
   (generate-boundary 40))
  ([n]
   (apply str "-------" (repeatedly n #(rand-nth *characters*)))))