writing zip file to file in Clojure - clojure

Question

I have a method for zipping:
(defn zip-project [project-id notebooks files]
(with-open [out (ByteArrayOutputStream.)
zip (ZipOutputStream. out)]
(doseq [nb notebooks]
(.putNextEntry zip (ZipEntry. (str "Notebooks/" (:notebook/name nb) ".bkr")))
(let [nb-json (:notebook/contents nb)
bytes (.getBytes nb-json)]
(.write zip bytes))
(.closeEntry zip))
(doseq [{:keys [name content]} files]
(.putNextEntry zip (ZipEntry. (str "Files/" name)))
(io/copy content zip)
(.closeEntry zip))
(.finish zip)
(.toByteArray out)))
after I make a zip I want to save it into the file something like /tmp/sample/sample.zip, but I cannot seem to make it. here is what I am doing:
(defn create-file! [path zip]
(let [f (io/file path)]
(io/make-parents f)
(io/copy zip f)
true))
The problem is, when I run unzip from terminal it says that zip file is empty and if I unzip it using Archive utility it extracts with cpgz extension.
What am I doing wrong here?

Answer 1

You will need essentially 4 things
Import everything (normally you would use (ns ...) but you can run this in the repl
(import 'java.io.FileOutputStream)
(import 'java.io.BufferedOutputStream)
(import 'java.io.ZipOutputStream)
(import 'java.util.zip.ZipOutputStream)
(import 'java.util.zip.ZipEntry)
You need a way to initialize the stream. This can be done nicely with the -> macro:
(defn zip-stream
"Opens a ZipOutputStream over the given file (as a string)"
[file]
(-> (FileOutputStream. file)
BufferedOutputStream.
ZipOutputStream.))
You need a way to create/close entries in the ZipOutputStream
(defn create-zip-entry
"Create a zip entry with the given name. That will be the name of the file inside the zipped file."
[stream entry-name]
(.putNextEntry stream (ZipEntry. entry-name)))
Finally you need a way to write your content.
(defn write-to-zip
"Writes a string to a zip stream as created by zip-stream"
[stream str]
(.write stream (.getBytes str)))
Putting it all together:
(with-open [stream (zip-stream "coolio.zip")]
(create-zip-entry stream "foo1.txt")
(write-to-zip stream "Hello Foo1")
(.closeEntry stream) ;; don't forget to close entries
(create-zip-entry stream "foo2.txt")
(write-to-zip stream "Hello Foo 2")
(.closeEntry stream))
The result: