How to return dynamic response from postman mock server?

Question

I want to return the dynamic response from the postman mock server.
When mock URL hits in the postman, we get request body and from request body I want to fetch the field value and return the value to response.

mock URL : {{url}}/customer
RequestBody:

{
    "Id": 47896,
    "name": userName
}

I want to send the Id value in the Response Body:

{
    "Id":47896
}

We are creating the random Id value in our project and we hit mock URL with that value in request body.
Every time the id value will be different after calling the mock URL. we are processing on the Id value if it mismatch then we throw an error.
Anyway to process the request body?
In the postman documentation, I didn't find any conclusive solution.

Answer 1

There is a limitation you can use dynamic value only in postman app not in newman .

https://github.com/postmanlabs/newman/issues/2565

In postman app you can :

Set response in mock server as :

   {
      "id":{{id}}
   }

Choose environment for mock server :

click edit and choose and environment.

Enable persist variable value settings

Note that this will update both initial and current value with the value you will set as pm.environment.set("name",valu") in your script.

Now set environment variable id through pre-reuest script:

pm.environment.set("id",5)

output

Note:

You should send request two times, first time for the environment to sync with cloud

and second to get updated response , so try to send a dummy request before the actual request .

IN old app it was working fine now it looks like you need two request.

Answer 2

You can use this code Snipped in your response body of mock server to achieve it.

   { 
    "id": "{{$body 'id' }}"
   }

I have also made a video for this. You can refer this video if you have any doubts

Answer 3

This is working for me: Contextual response example https://learning.postman.com/docs/designing-and-developing-your-api/mocking-data/creating-dynamic-responses/#contextual-response-example

Not working: @PDHide This should be we way to go, but it is only working with the Initial Value of the Enviroments.

I found this Comment from a Postman Collaborator from 03.04.2022:

"Thank you so much for reaching out to us. When you use a script to update environment variables that actually updates the current value of variables, and current values are local to your system and not shared with Postman systems. That's why when you try to use these variables with a mock server you are getting only the initial values in response. You can read more about the difference between initial and current values here. Hope you find this information useful!"

https://github.com/postmanlabs/postman-app-support/issues/10715

There was one work around mentioned in the community by praveendvd:

https://github.com/postmanlabs/postman-app-support/issues/9847

BR M.Kauf