Get access token from authorization code for REST Oauth 2.0 integration

[Wirasat]

Hi,

I have created an application registry entry for ServiceNow to connect to third party application. 

I need to get access token dynamically through script for REST API Oauth 2.0 integration as this access token expires every 30 minutes. I see scripts for grant type "Resource Owner Password Credentials" but couldn't find any script for grant type Authorization Code. 

[Mark A_ Miller]

I found that in order to select the grant type, I needed to modify the form layout on the Application Registry form by adding the Default Grant Type field.