# Get data from json response array **URL:** \ **Category:** Gatling (Open-Source)\ **Created:** [April 9, 2014, 1:37pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942 "2014-04-09T13:37:29Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Maxime\_Tual](https://avatars.discourse-cdn.com/v4/letter/m/a4c791/32.png) [@Maxime\_Tual](https://community.gatling.io/u/Maxime_Tual)\ **Post date:** [April 9, 2014, 1:37pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/1 "2014-04-09T13:37:29Z")
Hi, I’m working on Web Services who return data in JSON. Many of them returning data this way (simplify for the example): { “items”: [ { “id”: “123”, “name”: “test” }, { “id”: “456”, “name”: “other” } ], “pagingInfos”: {} } I cannot know how many items it will have in items array, I want to get one random item from this array, then get is “id” for use it in another Web Service. I found this in a previous post: [https://gist.github.com/slandelle/2469375](https://gist.github.com/slandelle/2469375) But I don’t succeed to change it for my conveniance, specially on the cast part. I got that for the moment: val getAll = exec(http(“Get one random friend”) .get("/users/${user\_id}/friendships") .header(“Authorization”, “Bearer ${access\_token}”) .check(status.is(200), jsonPath("$.items").findAll.saveAs(“user\_friends”))) .exec((session: Session) =\> { val friends = session(“user\_friends”).as[List[String]] session.set(“random\_friend”, friends(math.max(random.nextInt(friends.length), 9))) }) The exception on the line “as[List[String]]”: java.lang.ClassCastException: scala.collection.immutable.Vector cannot be cast to scala.collection.immutable.List at yelago.ws.GetUserFriendships$$anonfun$1.apply(GetUserFriendships.scala:22) ~[na:na] at yelago.ws.GetUserFriendships$$anonfun$1.apply(GetUserFriendships.scala:21) ~[na:na] at io.gatling.core.action.SessionHook.executeOrFail(SessionHook.scala:35) ~[gatling-core-2.0.0-SNAPSHOT.jar:2.0.0-SNAPSHOT] at io.gatling.core.action.Failable$class.execute(Actions.scala:97) ~[gatling-core-2.0.0-SNAPSHOT.jar:2.0.0-SNAPSHOT] at io.gatling.core.action.SessionHook.execute(SessionHook.scala:28) ~[gatling-core-2.0.0-SNAPSHOT.jar:2.0.0-SNAPSHOT] at io.gatling.core.action.Action$$anonfun$receive$1.applyOrElse(Actions.scala:30) ~[gatling-core-2.0.0-SNAPSHOT.jar:2.0.0-SNAPSHOT] Any help ? 🙂 Thanx ! ---
**Author:** ![Excilys](https://avatars.discourse-cdn.com/v4/letter/e/8797f3/32.png) [@Excilys](https://community.gatling.io/u/Excilys)\ **Post date:** [April 9, 2014, 1:48pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/2 "2014-04-09T13:48:25Z")
Well, a Vector is simply not a List 😉 Seq would be fine. But then, Gatling EL has a random() builtin You can use “${user\_friends.random()}” ---
**Author:** ![Maxime\_Tual](https://avatars.discourse-cdn.com/v4/letter/m/a4c791/32.png) [@Maxime\_Tual](https://community.gatling.io/u/Maxime_Tual)\ **Post date:** [April 9, 2014, 2:08pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/3 "2014-04-09T14:08:24Z")
> Humm that random method in EL will be great if I make it work. I have this first scenario: val getAll = exec(http(“Get all friends”) .get(“/users/${user\_id}/friendships”) .header(“Authorization”, “Bearer ${access\_token}”) .check(status.is(200), jsonPath(“$.items”).findAll.saveAs(“user\_friends”)) ) Follow by this second: val getOneRandomFriend = exec(http(“Get one random friend”) .get(“/users/${user\_friends.random().id}”) .header(“Authorization”, “Bearer ${access\_token}”) .check(status.is(200)) ) But got [ERROR] i.g.h.a.HttpRequestAction - No attribute named ‘user\_friends.random().id’ is defined Same error when I only put ${user\_friends.random()} ---
**Author:** ![Excilys](https://avatars.discourse-cdn.com/v4/letter/e/8797f3/32.png) [@Excilys](https://community.gatling.io/u/Excilys)\ **Post date:** [April 9, 2014, 2:11pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/4 "2014-04-09T14:11:18Z")
No, “${user\_friends.random().id}” is invalid Only “${user\_friends.random()}” is ---
**Author:** ![Maxime\_Tual](https://avatars.discourse-cdn.com/v4/letter/m/a4c791/32.png) [@Maxime\_Tual](https://community.gatling.io/u/Maxime_Tual)\ **Post date:** [April 10, 2014, 1:44pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/5 "2014-04-10T13:44:23Z")
> No, “${user\_friends.random().id}” is invalid > > Only “${user\_friends.random()}” is The random() EL method not working either (maybe because user\_friends was not consider as list ? I don’t know) Finally I end up using an external library call Dijon ([GitHub - jvican/dijon: A Dynamically Typed Scala Json Library](https://github.com/pathikrit/dijon)) which allow me to treat my JSON response as an object. Thanx anyway 🙂 ---
**Author:** ![Excilys](https://avatars.discourse-cdn.com/v4/letter/e/8797f3/32.png) [@Excilys](https://community.gatling.io/u/Excilys)\ **Post date:** [April 10, 2014, 1:50pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/6 "2014-04-10T13:50:02Z")
jsonPath("$.items") Why do you capture the whole object while you only need the id: jsonPath("$.[items.id](http://items.id)"), otherwise, as you wrote it, you’re capturing the full object String. ---
**Author:** ![Maxime\_Tual](https://avatars.discourse-cdn.com/v4/letter/m/a4c791/32.png) [@Maxime\_Tual](https://community.gatling.io/u/Maxime_Tual)\ **Post date:** [April 10, 2014, 2:14pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/7 "2014-04-10T14:14:32Z")
> Because as I say in the first post my json response is more complex and I cannot just use a jsonPath to fill my need. ---
**Author:** ![Excilys](https://avatars.discourse-cdn.com/v4/letter/e/8797f3/32.png) [@Excilys](https://community.gatling.io/u/Excilys)\ **Post date:** [April 10, 2014, 3:30pm UTC](https://community.gatling.io/t/get-data-from-json-response-array/942/8 "2014-04-10T15:30:45Z")
In both cases, you only want all the ids, not the full objects. What to do them them, either pick one randomly, or concat, comes in a second time. capture: jsonPath("$.[items.id](http://items.id)").findAll.saveAs(“itemIds”) random: “${itemIds.random}” concat: session =\> session(“itemIds”).validate[Seq[String]].map(\_.mkString(",")) // or whatever, I don’t know how you want to concat If you really want the objects: jsonPath("$.items").as[Map[String, Any]] Don’t use another parser. In terms of performance, you’ll shoot yourself in the foot!