API testing: add ability to store specific named values from json responses

[sampacos]

It would be very helpful to be able to store specific portions of web responses in order to use in subsequent requests. For example

• Send request to serviceX/api/v1/getUserByName?name=sampacos
• serviceX responds with json such as

{
  "userId": "1245235",
  "name": "sampacos",
  "age": "45",
  "userPreferences": {
    "autoSave": "true"
    "sessionId": "12344123123"
  }
}

• Send request to serviceY/api/v1/getProjectsByUserId?userId=1245235&sessionId=12344123123

What we need is the ability to store values from specific fields in the json to use for later requests.
In Gherkin, this might look something like this:

Given I use the API named ServiceX
When I add a parameter name with value sampacos
  And I send a GET request to the api/v1/getUserByName endpoint
Then I verify the response code is 200
  And I note the userId in the response
  And I note the userPreferences.sessionId in the response
When I use the API named ServiceY
When I add a parameter userId with the noted value
  And I add a parameter sessionId with the noted value
  And I send a GET request to the api/v1/getProjectsByUserId endpoint
Then I verify the response code is 200