Get a clojure reader using the encoding by the BOM

gistfile1.clj

(ns util
  (:require [clojure.java.io :refer (file)]
            [clojure.string :as str]
            [clojure.java.io :as io])
  (:import org.apache.commons.io.input.BOMInputStream
           org.apache.commons.io.ByteOrderMark))

(def bom-array
  (into-array [ByteOrderMark/UTF_16LE
               ByteOrderMark/UTF_16BE
               ByteOrderMark/UTF_8
               ByteOrderMark/UTF_32BE
               ByteOrderMark/UTF_32LE]))

(defn bom-reader
  "Returns a BOM contextual reader with the proper encoding set (= BOM)"
  [file]
  (let [bom (-> file
                io/input-stream
                (BOMInputStream. true bom-array))
        encoding (.getBOM bom)
        encoding (if (nil? encoding) "UTF-8" (.getCharsetName encoding))]
    (io/reader bom :encoding encoding)))