We are aware of the fact that OAuth 2.0 feature was made available in 7.2. We are trying to connect to an API that has OAuth 2.0 security protocol and our application is built on 7.1.9. Apparently we have no scope for upgrading our application to 7.2. So is there any work around to connect to this API. If it has been implemented in 7.2 there must be some activities or other OOTB rules that can be crafted in 7.1.9.
If I were you, I would install a pega 7.2 system (for simplicity may be a PE version). Start with the Data-Admin-Auth-Service
There you can find the pzOAuth2AuthenticationActivity for authentication and I am not how feasible it is to backport the stuff to 7.1.9 - If you just want to use part of the implementation details you may be able to use some of the examples there.
There is also another auth-service OAuthResourceAuthentication to handle token authentication.
The end connection to the Resource Server(API Server) will be through a REST Connector. As in 7.1.9 we cannot use OAuth 2.0 along with REST connector OOTB, We were planning to use 2 REST connectors. The first one to get the access token from the AUTH server through a POST method and save it in a clipboard property and then send this access token to the Resource Server through the POST method of another REST connector. But the idea to make two explicit calls has been adjourned as of now.
The API is using OAuth 2.0 with client credentials grant type. We are currently looking for a way to implement this without making 2 explicit calls and automate the entire process of getting the access token and sending it to the API in a single call.