Null Attribute Error

Gatling (Open-Source)
1

I have one endpoint which will return response in below format:
{
“items”:[ { …}],
“nextPage”:27ubdkj
}
If “items” array length is within 10, then “nextPage” value will be null.
{
“items”:[ { …}],
“nextPage”:null
}

In gatling script, I am extracting the “nextPage” value using check method:
.check(jsonPath(“$.nextPage”).optional.saveAs(“basicNextPage”))

And, in my scenario, I have do while loop asserting whether “nextPage” value is exists or not and based on that executing another request:
exec(getAllEntitlements)
.doWhile(“${basicNextPage.exists()}”) {
exec(getAllEntitlementsAndPage)
}
While running this script, I am getting error “[ERROR] i.g.h.a.HttpRequestAction - ‘httpRequest-33’ failed to execute: Attribute basicNextPage’s value is null”.

How to fix this?

2

Beware that exists() only checks for the existence of the key, even if the value is null.
You probably have to write a more complex test condition with the Session API.

doWhile(session => ???)

3

I tried having a query like this :
doWhile(session => session("basicNextPage").asOption[String].isDefined) and
asLongAs(session => session("basicNextPage").asOption[String].isDefined)
But still getting same error “[ERROR] i.g.h.a.HttpRequestAction - ‘httpRequest-33’ failed to execute: Attribute basicNextPage’s value is null”.

Can you provide me some example to fix this issue?

4

If you struggle with Option, I guess you struggle with scala in general. You know you can write Gatling Simulation in java?

To answer you specific question:

  doWhile(session => Option(session("basicNextPage").as[String]).isDefined)

Cheers!

5

I have used the above condition, but still facing the error
Condition evaluation crashed with message 'j.l.ClassCastException: Attribute basicNextPage's value is null', exiting loop

Code snippet:

asLongAs(session => Option(session("basicNextPage").as[String]).isDefined)

I have provided the httprequestbuilder which I have been using:

  val getAllEntitlements: HttpRequestBuilder = getEntitlementByAccount("entitlement_GetAllEntitlements","")
    .check(jsonPath("$.items").notNull)
    .check(status is 200)
    .check(jsonPath("$.nextPage").optional.saveAs("basicNextPage"))

  val getAllEntitlementsAndPage: HttpRequestBuilder = getEntitlementByAccount("entitlement_GetAllEntitlementsAndPage","page=${basicNextPage}")
    .check(jsonPath("$.items").notNull)
    .check(status is 200)
    .check(jsonPath("$.nextPage").optional.saveAs("basicNextPage"))

Also provide the scenario in which way I have constructed calling APIs:

exec(getAllEntitlements)
  .asLongAs(session => Option(session("basicNextPage").as[String]).isDefined) {
    exec(getAllEntitlementsAndPage)
  }

Please provide some solution to fix this issue!

6

Ok, my bad, I didn’t test the case for JSON null type.

So, you can use the session.attributes Map to be able to get your value.

asLongAs(session => session.attributes.get("basicNextPage").filterNot(_ == null).isDefined)

or shorter:

asLongAs(session => !session.attributes.get("basicNextPage").forall(_ == null))

Cheers!

7

Thank You @sbrevet for your support in solving this issue.