How to update a value in a .txt using in a post request ?

Gatling (Open-Source)
1

Hello everybody, i’m trying to write a test which create new user on our ASP.NET app. The app use some old security mechanism like state variable (__VIEWSTATE and __EVENTVALIDATION). The gatling recorder create a file named CreatePratician_0006_request.txt. But in order to be able to replay the scenario, i have to replace some values extracted from the incoming request in that file. Sadly, i have no idea how to accomplish such a task ?

.exec(http("request_5")
 .post("/app/Services/AppAjax.asmx/SetSelectedRegion")
 .headers(headers_4)
 .body(RawFileBody("CreateUser_0005_request.txt"))
 .check(bodyBytes.is(RawFileBody("Createuser_0005_response.txt"))))
.pause(5)




The file with the request parameters is in attachment. 



Thx



PS: Does someone have any good tips or resources on how to use gatling with ASP.NET app ?

CreatePratician_0006_response.txt (55.9 KB)