clj-jq

A Clojure library designed to make working with JSON objects simpler and faster. This wraps the jq native library that is provided by com.arakelian/java-jq.

Leiningen

[me.bwest/clj-jq "1.0.0"]

Maven

<dependency>
  <groupId>me.bwest</groupId>
  <artifactId>clj-jq</artifactId>
  <version>1.0.0</version>
</dependency>

Usage

Very simply, 4 methods are provided

(require '[clj-jq.core :as jq])

(def json-str "{\"a\": 2, \"foo\": \"bar\", \"baz\": {\"x\": 10, \"y\": \"20\"}}")

(let [doc (jq/prepare json-str)
      a (jq/query doc ".a")
      foo (jq/query doc ".foo")
      x (jq/query doc ".baz.x")]
  (is (= 2 a))
  (is (= "bar" foo))
  (is (= 10 x)))

You can alias a jq request with jq/prepare and then query it multiple times. Or you can simply call jq/query directly on the string and it will prepare the document behind the scenes.

Note that preparing does not give a performance advantage here because this simply calls the jq library with each request execution. Some work could be done to take in a map of requests and parse it, but I haven't taken the time to do that. You could do that directly with the jq query string, though.

This also exposes jq/read which is just an alias of (clojure.data.json/read-str x :key-fn keyword) and jq/write, which just aliases clojure.data.json/write-str

If you want to map an incoming JSON message to some consistently structured map, jq can do that:

(jq/query json-str "{\"id\": .inbound.payload.messageId, \"url\": .inbound.payload.docUrl, \"date\": .metadata.originDate}")

This will yield a map with the structure:

{:id <id> :url <url> :date <date>}

Values can then be mapped further into specialized data types using normal Clojure functions.