download-package-lock.clj

(ns build
  (:require [clojure.tools.build.api :as b]
            [shadow.cljs.devtools.api :as shadow.api]
            [shadow.cljs.devtools.server :as shadow.server]
            [cheshire.core :as json]
            [clojure.java.io :as io]
            [clojure.string :as string])
  (:import (org.apache.commons.compress.archivers ArchiveStreamFactory)
           (java.util.zip GZIPInputStream CheckedInputStream Adler32)
           (java.security MessageDigest DigestInputStream)
           (java.util Formatter)))



(defn ^MessageDigest message-digest-instance
  [integrity]
  (MessageDigest/getInstance (first (string/split integrity #"-" 2))))

(defn md-integrity
  [^MessageDigest md]
  (let [formatter (Formatter.)
        hash (.digest md)]
    (doseq [i hash]
      (.format formatter "%02x" (into-array [i])))
    (str formatter)))

(set! *warn-on-reflection* true)
(defn x []
  (let [{:strs [packages]} (json/parse-stream (io/reader "package-lock.json"))
        packages (remove #(get % "dev")
                   (dissoc packages ""))]
    (doseq [[target {:strs [resolved integrity]}] packages
            :let [targetf (io/file target)
                  md (message-digest-instance integrity)
                  in (DigestInputStream. (io/input-stream resolved) md)
                  tar (.createArchiveInputStream (ArchiveStreamFactory.) "tar"
                        (GZIPInputStream. in))]]
      (loop []
        (when-let [tar-entry (some-> tar .getNextEntry)]
          (let [entry-target (io/file targetf (string/replace (.getName tar-entry)
                                                #"^package/"
                                                ""))]
            (io/make-parents entry-target)
            (io/copy tar entry-target)
            (recur))))
      (prn [integrity (md-integrity md)]))))