How to save a global variable in Postman from a pre-request script that must throw a validation error

Question

This scenario used to work in a previous version of Postman this year:

call postman.setGlobalVariable('test', 'my_value') in a pre-request script
let the pre-request script finish by throwing an Error (this is required because I have to validate the environment variables)
after the Postman request is executed (with the Error thrown in pre-request script) the global variable test with value my_value is available in the Globals list.

In the current (5.2.1) version of Postman the global variables are not persisted from a pre-request script that throws an Error.

Is there a way to enable this?
Is there a way to work around this?

My use case is implementing a guard for DELETE REST calls to avoid unintentional deletion of server-side objects. The user had to send the same request (press Send) a given amount of times in order to make sure he really wants to execute this request. This was achieved and worked until recently using global variables.

A.Joly A.Joly · Accepted Answer · 2017-10-06T12:03:58

I think you could make a workaround if you set your url as a global or environment variable and use {{url}} in your request.

If so, in the prerequest script, you can set it to an invalid value, which avoids to send the proper request and your other global will be set.

You could condition that update to a certain amount of clicks, or whatever, that you would set in your other global. ie.

var counter = postman.getGlobalVariable('counter'); 

if (counter == undefined)
{
    postman.setGlobalVariable('counter', 0); // initialize counter if not exists
}

var validurl= postman.getGlobalVariable('valid_url') 
var current_url= postman.getGlobalVariable('url') // keep the current url which is valid

if (validurl == undefined)
{ 
    postman.setGlobalVariable('valid_url', current_url) // store the valid url if not done yet
}


counter = parseInt(counter) + 1 // then if you call it three times it should execute ...
console.log("info counter " + counter)
postman.setGlobalVariable('counter', counter)
if (counter < 3) // let say three tries, to be sure
{
    pm.globals.set("url", "dummy"); // other syntax, no matter => request fails
}
else
{ 
    // set back url
     pm.globals.set("url", validurl);
}

I think something like that could meet your requirements ...

How to save a global variable in Postman from a pre-request script that must throw a validation error

1 Answers