Consume 3rd party REST service with Content-Type=application/x-www-form-urlencoded

I am trying to consume a 3rd party REST service with Content-Type=application/x-www-form-urlencoded

I have tested different approach with Postman.

It can be done with a POST or a GET with those configurations:

Header : Content-Type = application/x-www-form-urlencoded

Header : Autorization = Basic <client_id>:<client_secret>

Body : grant_type=client_credentials&scope=https://graph.microsoft.com/.default

I have tried to replicate this with PeopleCode using both a POST and a GET and both are not working for different reasons.

 

Here is the basic of what I'm trying to do with PeopleCode:

&msg = CreateMessage(Operation.<service_operation_POST>); or &msg = CreateMessage(Operation.<service_operation_GET>);