# Extracting map from session and using inside headers()

**URL:** <https://community.gatling.io/t/extracting-map-from-session-and-using-inside-headers/2560>\
**Category:** Gatling (Open-Source)\
**Created:** [September 25, 2015, 3:38am UTC](https://community.gatling.io/t/extracting-map-from-session-and-using-inside-headers/2560 "2015-09-25T03:38:28Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Ashish\_Rathore](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Ashish\_Rathore](https://community.gatling.io/u/Ashish_Rathore)\
**Post date:** [September 25, 2015, 3:38am UTC](https://community.gatling.io/t/extracting-map-from-session-and-using-inside-headers/2560/1 "2015-09-25T03:38:28Z")

</div>

Hello Folks,

I have a case where a session variable (a Map) need to be used for **http().headers(Map).**

Currently I get below compile error when trying to do so:

20:30:45.333 [ERROR] i.g.c.ZincCompiler$ - …/user-files/simulations/myserver2/DownloadFromServer.scala:138: Cannot prove that Char \<:\< (String, String).

20:30:45.333 [ERROR] i.g.c.ZincCompiler$ - .headers("${headersMap}".toMap[String, String])

Here is a snippet of code:

scenario(“Setup Call”)

.exec(Some\_Chain\_Populating\_Session\_Map)

.exec(

http(“Setup Call”)

.post(“[https://URL/](https://URL/)”)

.header(“someSimpleHeader”, session =\> custom\_header2(session))

.headers("${headersMap}".toMap[String, String]) \<\<\<\<\<\<------------------------- Error’d out line

)

})

If session Map is not possible, what are our options? Iterating over Map followed by adding “.header()” inside http() call?

Thanks,  
Ashish

---

<div class="post-metadata">

**Author:** ![Jian\_Guan](https://avatars.discourse-cdn.com/v4/letter/j/aeb1de/32.png) [@Jian\_Guan](https://community.gatling.io/u/Jian_Guan)\
**Post date:** [June 14, 2019, 8:35am UTC](https://community.gatling.io/t/extracting-map-from-session-and-using-inside-headers/2560/2 "2019-06-14T08:35:09Z")

</div>

Hi ashisa:  
Do you resolve this issue? I suffer from it too.

Hoping your help.

---

<div class="post-metadata">

**Author:** ![Jian\_Guan](https://avatars.discourse-cdn.com/v4/letter/j/aeb1de/32.png) [@Jian\_Guan](https://community.gatling.io/u/Jian_Guan)\
**Post date:** [June 14, 2019, 8:38am UTC](https://community.gatling.io/t/extracting-map-from-session-and-using-inside-headers/2560/3 "2019-06-14T08:38:04Z")

</div>

Hi Ashash:  
Have you resolve it? I suffer from it too.

Thanks

my code as follow:

```auto
object AuthenticationExec {

  val login =
      feed(csv("execFeeders/login.csv").batch.random)
      .exec{ session=>
        val rq = new LoginRq()
        val body = rq.getBody(session("loginType").as[String], session("user").as[String], session("password").as[String])
        val url = rq.getUrl()
        val headers = rq.getHeader().asScala.toMap
        session.set("body",body).set("url",url).set("header",header)
      }
      .exec(
        http(Thread.currentThread().getStackTrace()(2).getMethodName())
        .post("${url}")
        .headers("${header}".toMap[String,String])
        .body(StringBody("${body}")).asJson
        .check(status.is(201))
        .check(jsonPath("$.token").saveAs("User-Token")))
}

```

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