Add option user_params to oauth2.0_token to enable endpoint-specific access parameters. #312
This branch holds the implementation for passing additional access parameters in the form of a list of named values to the oauth2.0_token function. The function refresh_oauth2.0 was modified accordingly.
The service account functionality was not touched. My only reference for the use of user_params, Microsoft Azure AD, uses quite different parameters for service-to-service authorization when compared to httr's init_oauth_service_account. See https://msdn.microsoft.com/en-us/library/azure/dn645543.aspx.
A demo for the Azure AD endpoint was added. In the committed version it uses dummy credentials and will run but not succeed.
While viewing the diffs on github, I noticed a possible typo in the demo/00Index line
…als. Rd files have not yet been created and tests have not been run.
… pass additional parameters during token access or refresh as required by endpoints like Azure AD.