Fetching nested JSON values from session attributes

Neil · August 20, 2014, 3:11pm

I am trying to parse the following response and do some calculation on id and version .

`

{
  "result": "SUCCESS",
  "data": [
    {
      "playerId": {
          "id":2,
          "version":1
      },
      "score":200
    }
  ]
}

`

Code is

`
package computerdatabase

import io.gatling.core.Predef._
import io.gatling.http.Predef._
import scala.concurrent.duration._
import io.gatling.jsonpath._

class Test1 extends Simulation {

//Global Users
val userMap = scala.collection.concurrent.TrieMapString, String
//Randomiser
val rnd = new scala.util.Random
val httpConf = http
.baseURL(“http://demo1263864.mockable.io/”) // Here is the root for all relative URLs
.acceptHeader(“application/json”) // Here are the common headers
.doNotTrackHeader(“1”)
.acceptLanguageHeader(“en-US,en;q=0.5”)
.acceptEncodingHeader(“gzip, deflate”)
.userAgentHeader(“Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:16.0) Gecko/20100101 Firefox/16.0”)

val headers_10 = Map(“Content-Type” → “application/json”) // Note the headers specific to a given request

val scn = scenario(“Simple request”)
.exec(
http(“If request “)
.get(“gatling1”)
.headers(headers_10)
.check(jsonPath(”$.result”).is(“SUCCESS”),
jsonPath("$.data[*]").ofType[Map[String, Any]].findAll.saveAs(“pList”)))
.foreach("${pList}", “player”) {
exec(session => {
val playerMap = session(“player”).as[Map[String, Any]]
val playerId = playerMap(“playerId”).asInstanceOf[Map[String, Any]]
val id = playerId(“id”)
println(id)
session.set(“playerId”, playerId)
})
}

setUp(scn.inject(atOnceUsers(1)).protocols(httpConf))
}Enter code here…
`

The line

val playerId = playerMap(“playerId”).asInstanceOf[Map[String, Any]]

Errors out with

20:36:15.860 [ERROR] i.g.c.a.b.SessionHookBuilder$$anonfun$build$1$$anon$1 - Action anonfunbuild1anon1 crashed on session Some(Session(Simple request,4173992086124673397-0,Map(8d6aa6d4-3c7e-4e8f-b475-db8bfe5094e1 → 0, pList → Vector(Map(playerId → {id=2, version=1}, score → 200)), timestamp.8d6aa6d4-3c7e-4e8f-b475-db8bfe5094e1 → 1408547175843, player → Map(playerId → {id=2, version=1}, score → 200), gatling.http.cookies → CookieJar(Map())),1408547175294,71,OK,List(ExitOnCompleteLoopBlock(8d6aa6d4-3c7e-4e8f-b475-db8bfe5094e1)))), forwarding to the next one
java.lang.ClassCastException: org.boon.core.value.LazyValueMap cannot be cast to scala.collection.immutable.Map
at computerdatabase.Test1$$anonfun$1.apply(Test1.scala:34) ~[na:na]
at computerdatabase.Test1$$anonfun$1.apply(Test1.scala:32) ~[na:na]
at io.gatling.core.action.SessionHook.executeOrFail(SessionHook.scala:35) ~[gatling-core-2.0.0-RC2.jar:2.0.0-RC2]
at io.gatling.core.action.Failable$class.execute(Actions.scala:71) ~[gatling-core-2.0.0-RC2.jar:2.0.0-RC2]
at io.gatling.core.action.SessionHook.execute(SessionHook.scala:28) ~[gatling-core-2.0.0-RC2.jar:2.0.0-RC2]
at io.gatling.core.action.Action$$anonfun$receive$1.applyOrElse(Actions.scala:29) ~[gatling-core-2.0.0-RC2.jar:2.0.0-RC2]
at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:166) ~[scala-library.jar:na]
at akka.actor.Actor$class.aroundReceive(Actor.scala:465) ~[akka-actor_2.10-2.3.4.jar:na]
at io.gatling.core.akka.BaseActor.aroundReceive(BaseActor.scala:23) ~[gatling-core-2.0.0-RC2.jar:2.0.0-RC2]
at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516) ~[akka-actor_2.10-2.3.4.jar:na]
at akka.actor.ActorCell.invoke(ActorCell.scala:487) ~[akka-actor_2.10-2.3.4.jar:na]
at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238) ~[akka-actor_2.10-2.3.4.jar:na]
at akka.dispatch.Mailbox.run(Mailbox.scala:220) ~[akka-actor_2.10-2.3.4.jar:na]
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393) [akka-actor_2.10-2.3.4.jar:na]
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [scala-library.jar:na]
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [scala-library.jar:na]

How do I handle nested maps ?

Pierre_DAL-PRA · August 20, 2014, 3:37pm

Ah, this actually looks like a bug…
Will investigate.

In the mean time, you can still get each value separately :

`
.check(
jsonPath("$.result").is(“SUCCESS”),
jsonPath("$.data.playerId.id").ofType[Seq[Int]].findAll.saveAs(“playerIds”)
jsonPath("$.data.playerId.version").ofType[Seq[Int]].findAll.saveAs(“playerVersions”)
)

`

This will save one list of ids and one list of versions in the session, which you can then put back together should you need to :

`
case class Player(id: Int, version: Int)

.exec(session => {
val playerIds = session(“playerIds”).as[Seq[Int]]
val playerVersions = session(“playerVersions”).as[Seq[Int]]
val players = (playerIds, playerVersions).zipped.map(Player.apply))
session.set(“players”, players)
})
`

This last piece of code :

fetches the two lists from the session
“zips” the lists, e.g. (List(1,3), List(2, 4) ==> List((1,2), (3,4))
Builds a list of Player from the previous lists

Hope this helps !

Cheers,

Pierre

Neil · August 20, 2014, 3:53pm

Thanks Pierre,
I did think about this individual list workaround . The problem is that my actual JSON format is deeply nested and complex in nature ,so wanted a straight forward way to deal with a block of JSON at a time. Basically the requirement is similar to obtaining those playerIDs whose version is 1. There is an old post which uses some Json library to do so but I wanted to have a loop and filter.

Still I will try this approach.
Let me know in case you decide to file a bug so that I can follow.

Neil · August 21, 2014, 6:15am

I settled for the following which is similar to Pierre’s code

`
.check(
jsonPath("$.result").is(“SUCCESS”),

jsonPath("$.data.playerId.id").findAll.saveAs(“playerIds”)
jsonPath("$.data.playerId.version").findAll.saveAs(“playerVersions”)
)

`

Note: casting to as[Seq[Int]] game me error
`

.exec(session => {

val playerIds = session(“playerIds”).as[Vector[String]]
val playerVersions = session(“playerVersions”).as[Vector[String]]
playerIds.indices.foreach { i =>
if (playerVersions(i) == 1) {
filteredPlayerIds += playerIds(i)
}
}
})
`

Anything other than as[Vector[String]] gave me error

Pierre_DAL-PRA · August 21, 2014, 1:52pm

Hi Neil,

You need to specify that id and version are to be treated as Ints, or they’re saved as Strings.

This works (unfortunately there was a slight error in my previous example) :

jsonPath("$.data.playerId.id").ofType[Int].findAll.saveAs("playerIds") jsonPath("$.data.playerId.version").ofType[Int].findAll.saveAs("playerVersions")

Then you can get it back as a Vector[Int].

Cheers,

Pierre

Till_Neunast · April 24, 2016, 5:26am

Hi,

Though an old thread, I thought I’d post a suggestion as I’ve come across a similar situation.

I found that the Gatling JsonPath implementation (import io.gatling.jsonpath.JsonPath) with its filter conditions could work here (at least for simple filter logic):

`
jsonPath("$.data[?(@.playerId.version == 1)]").ofType[Any].findAll.saveAs(“filteredPlayers”)

`
Then you can do what you like with the saved player objects later on.

Or, if you’re only interested in the ids, to get your Vector[Int]:

`
jsonPath("$.data[?(@.playerId.version == 1)]").ofType[Any].findAll
.transform(_.map(JsonPath.query("$.playerId.id", _).right.get.next.asInstanceOf[Int]))
.saveAs(“filteredPlayerIds”)

`

However, if your filter expression is too complex for JsonPath, you could do:

jsonPath("$.data[*]").ofType[Any].findAll .transform(_.filter(JsonPath.query("$.playerId.version", _).right.get.next.asInstanceOf[Int] == 1)) .saveAs("players")

Anyhow, the transform step eliminates the need for your forEach loop.

HTH,
Till

slandelle · April 26, 2016, 9:08pm

Yep, you can do that.
But you’d better compile your paths once and for all if they’re static, instead of over and over again.

Manohari · August 8, 2016, 10:31am

hi,
{“id”:30,“result”:{“moreRows”:0,“landmarkList”:[{“id”:“40542263”,“lastUpdate”:“2016-07-15 16:27:45”},{“id”:“40542309”,“lastUpdate”:“2016-07-15 16:27:45”},{“id”:“47891637”,“lastUpdate”:“2016-07-15 16:27:45”},{“id”:“47891639”,“lastUpdate”:“2016-07-15 16:27:45”},{“id”:“40542383”,“lastUpdate”:“2016-07-15 16:27:45”}]}}

how can i get id’s from the above json

Thanks in Advance

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Fetching nested JSON values from session attributes

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