When doing integrations from Salesforce you sometimes need to do this using single identity instead as in the context of the current user. Salesforce supports both through Named Credentials i.e. both working as the current user or as a Named Principal. Through the Named Credentials and Auth. Provider concepts from Salesforce you can setup a connection between Salesforce and an OAuth 2.0 enabled endpoint such as Microsoft Azure i.e. if needing the access the Microsoft Graph API. This can however be an issue as the target system (i.e. Microsoft Azure in this case) may not use a user that is able to login or you may not want to use a user license in the target system.
In this case you might want to use the
client_credentials OAuth flow as that identifies the caller using a
client_id and a
client_secret instead of a user id. Unfortunately that OAuth flow type is not supported out-of-the-box with Salesforce. The reason is that the Auth. Providers in Salesforce usually deals with a user behind the keyboard. Due to this the OAuth 2.0 Auth. Provider flows was designed for a
refresh_token World. This makes it impossible to use the built in capabilities for the
The solution is to write a custom Auth. Provider in Apex and use that from your Named Credential. To make this easier I’ve already implemented this for you. The code is available on Github in my salesforce-azure-clientcredentials-authprovider repo. This implementation just plays along with the
refresh_token requirements and just requests a new
access_token using the
client_credentials flow whenever a (new)
access_token is needed and hence do not need a user behind the keyboard.
README.md in the repo has instructions for installing and configuring the code in the org. Once deployed you can create an Auth. Provider and a Named Credential. Please note you also need to create an App Registration in Azure Active Directory with the required Application Permissions.