Unable to extract and use GUID

[krishnendusen72]

My requirement is to generate one authorization url where multiple queryparam are present which I am taking from custom attribute. One queryparam is "state" in which I want to assign GUID. which I have created using javascript policy.

here is my code:

function guid() { function s4() { return Math.floor((1 + Math.random()) * 0x10000) .toString(16) .substring(1); } return s4() + s4() + '-' + s4() + '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4(); } var uuid = guid(); context.setVariable('response.header.x-apigee-uuid', uuid);

while using that uuid in queryparameter it is taking as null value.
Note: In trace the uuid is coming as read only. I am not sure whether this is the reason of taking the value as null.

[dknezic]

Can you explain in more detail where you're expecting this guid to go? It seems you're setting it as a response header, so it goes back to your API Consumer as a header?

[dchiesa1]

Yes, and.... the snapshot of the Trace (thank you for that) has an equals sign with a cross through it. This means the assignment did not happen.

Your policy (maybe the JavaScript) *tried* to assign that uuid to a header, but it did not succeed.

?why?

I suspect it may be because the JavaScript is running in the request flow, before the response message is available. You cannot assign to "response.header.ANYTHING" within a policy if the policy is attached in the request flow.

So.. make sure that

• you're assigning to the correct message. Eg response vs request
• you're assigning to the correct thing within the message. Eg queryparam vs header.

You may want to try assigning to request.queryparam.uuid , if you are expecting the upstream (backend) system to receive a uuid in a queryparam.

You may want to try assigning to request.header.uuid , if you are expecting the upstream (backend) system to receive a uuid in a request header.