How to write some transit-clj in a file and how to retrieve the data structure from this file

Question

Say I have:

(def c [{:id 12 :name "John"}])

How do I write this in a file?

How do I get back this data structure?

Answer 1

A not perfect solution that works:

(require '[clojure.java.io :as io]
         '[cognitect.transit :as t])

(def c [{:id 12 :name "John"}])

(def dir "resources/json/")

(defn write-transit [dir file-name file-type coll]
  (let [suffix {:json ".json" :json-verbose ".verbose.json" :msgpack ".mp"}]
    (with-open [out (io/output-stream 
                      (str dir "/" file-name (file-type suffix)))]
        (t/write (t/writer out file-type) coll)))))

(defn read-transit [dir file-name file-type]
  (let [suffix {:json ".json" :json-verbose ".verbose.json" :msgpack ".mp"}]
    (with-open [in (io/input-stream (str dir "/" file-name (file-type suffix)))]
      (t/read (t/reader in file-type)))))

(write-transit dir "test" :json c)
;=> nil

(read-transit dir "test" :json)
;=> [{:id 12 :name "John"}]

Answer 2

Take a look at the code in the doc to read, especially at the bottom. There's a complete example of what you're looking for.