Remove #inst and #uuid literals in clojure

Question

I have UUID and java date that receive literals like #uuid and #inst, how can I specify uuid or date without referring to the literals themselves? clj-json does not like to deal with them and eventually throws an error when I try to create a string

{:timestamp (java.util.Date.)} ;{:timestamp #inst "2013-05-17T13:45:24.095-00:00"} ;but as a string the date changes format {:timestamp (str (java.util.Date.))} {:timestamp "Fri May 17 09:45:44 EDT 2013"} (json/generate-string {:uuid (java.util.UUID/randomUUID)}) ;#uuid "d66cf77f-13b6-4291-95cd-c2bb40aa36b3" java.lang.Exception: Cannot generate d66cf77f-13b6-4291-95cd-c2bb40aa36b3 JsonExt.java:96 clj_json.JsonExt$Generator.generate JsonExt.java:83 clj_json.JsonExt$Generator.generate JsonExt.java:103 clj_json.JsonExt.generate core.clj:18 clj-json.core/generate-to-writer core.clj:26 clj-json.core/generate-string NO_SOURCE_FILE:32 myapp.handler/eval8390 

Answer 1

Not sure, but it looks like you need:

 user=> (str (java.util.UUID/randomUUID)) "91d7fcc5-d24d-4e33-a111-6ba69d14eb6a" 

For the date you need to choose the correct format. I.e:.

 user=> (import java.text.SimpleDateFormat) java.text.SimpleDateFormat user=> (.format (SimpleDateFormat. "yyyy/MM/dd HH:mm:ss") (java.util.Date.)) "2013/05/17 16:49:58" 

Answer 2

You can use this library which supports UUID and Dates https://github.com/dakrone/cheshire

According to the project page, "Cheshire is fast JSON encoding based on clj-json and clojure -json, with additional features like Date / UUID / Set / Symbol encoding and SMILE support."

Answer 3

A timestamp is an object that does not have a “format”. You can choose the format as text yourself or use, for example. cheshire to create JSON. Cheshire knows which date format is suitable for JSON and can do the conversion.

 user> (def x (java.util.Date.)) #'user/x ; x points to a Date object (not text) 

Clojure printer knows how to present binary objects to people:

 user> x #inst "2015-02-13T06:24:09.629-00:00" user> (pr-str x) "#inst \"2015-02-13T06:24:09.629-00:00\"" 

You can choose the text view yourself:

 user> (str x) "Fri Feb 13 08:24:09 EET 2015" ; default format of java.util.Date user> (.format (java.text.SimpleDateFormat. "yyyy-MM-dd'T'HH:mm:ss.SSSXXX") x) "2015-02-13T08:24:09.629+02:00" 

Just to make the difference understandable, an object can also be represented as byte values, without loss:

 user> (def outs (java.io.ByteArrayOutputStream.)) #'user/outs user> (doto (java.io.ObjectOutputStream. outs) (.writeObject x) (.close)) #<ObjectOutputStream java.io.ObjectOutputStream@2bd682ed > user> (seq (.toByteArray outs)) (-84 -19 0 5 115 114 0 14 106 97 118 97 46 117 116 105 108 46 68 97 116 101 104 106 -127 1 75 89 116 25 3 0 0 120 112 119 8 0 0 1 75 -127 -101 -39 -99 120) 

Answer 4

For date and time materials, you are best off using clj-time, which is a wrapper around joda time libraries. This avoids the need to deal with fuzzy java date, time calendar, formatting.

I also recently saw a clj-uuid library on github that could work with uuids a bit more clojurish