SoapUI testing: remove quotation marks from session ID - testing

Question

So, I am new to SoapUI, and working with API's in general, but I am trying to set up an automated test for a REST API in SoapUI (the freeware version).
The first call I make returns a session ID in JSON, which is placed between quotation markslike: "session ID goes here". This key is needed, without quotation marks, in the next API call. I use SOAPUI's "Property Transfer Teststep", and this is working well, apart from the quotationmarks which are still around the session ID, resulting in an error responce by the subsequent call.
Any idea how I can remove the quotation marks? Ive been reading up/Googling on Xpath and JSONPath, which are some of the coding languages I can use in the screen, but I cant see how to use this to remove said quotation marks.
Your help would be greatly appreciated!!
Full RAW Response:
HTTP/1.1 200 OK Cache-Control: no-cache Pragma: no-cache Content-Type: application/json; charset=utf-8 Expires: -1 Server: Microsoft-IIS/8.5 X-AspNet-Version: 4.0.30319 X-Powered-By: ASP.NET Date: Tue, 02 May 2017 18:31:48 GMT Content-Length: 38 "48d45ba2-4549-41be-8b31-e85b3c738a03"

Answer 1

you say that the message is returned as "48d45ba2-4549-41be-8b31-e85b3c738a03". Although the message says it is json, that does not mean that SoapUI will interprete it as valid json. Valid JSON like in the question referred to in another answer, starts and ends with curly brackets. Also it should have a key and value pair. Like so:
{
"sessionId":"48d45ba2-4549-41be-8b31-e85b3c738a03"
}
In that case the transfer $.sessionId would yield 48d45ba2-4549-41be-8b31-e85b3c738a03(without quotation marks), and not "48d45ba2-4549-41be-8b31-e85b3c738a03" (with quotation marks).
In attachment there is a project with a mock. It has got one call. If you open the project, you have to launch the mock by clicking play, then you can execute the test case. - https://www.dropbox.com/s/rsgc9q1g45jze5z/StackOverflow_43745255_QuestionQuotationMarks.xml?dl=0. You can save this as XML, then you can open it with SoapUI.
You will see a property transfer step. It has one step that is passed. Then one where you transfer the value without any paramter. It will transfer the message in full. Including the quotation marks.
The sencond transfer is '$'. For a valid json, this would render the same result as for the property transfer without any parameter because '$' represents the root. At least that is how I understand it.
Included you will also find a script:
response = context.testCase.getTestStepAt(0).testRequest.response.getResponseContent()
assert response == '"48d45ba2-4549-41be-8b31-e85b3c738a03"'
stripResponse = response.replace("\"", "")
assert stripResponse == '48d45ba2-4549-41be-8b31-e85b3c738a03'
The stripResponse is the response where the quotation marks are stripped away. You could then proceed to assign this variable to a property of choice, or inject it directly in the headers of a next step.
Sometimes scripting is the way to go.