We are evaluating accessing SalesForce services from our custom portal. We even investigate implementing SAML based SSO to simplify login to both systems. However, to create new records in SalesForce as the user currently logged in in our custom portal, REST-API calls has to contain proper session ID.
How can I efficiently get this user's session ID?
We don't have an access to user passwords stored in our portal so it is not possible to get SalesForce session ID via SOAP login (as I usually do).
Does SSO bring any advantages here when it comes to REST-API calls between both systems?