Differentiation between the methods of obtaining the userPrincipal calling the function

[Severin]

@yk-saito

Am I correct in understanding that, for example, if we assume that the user using the application is authenticated by Internet Identity, it is best to retrieve it with caller() rather than having the front end specify the Principal as an argument?

Yes, that’s right. Otherwise someone could modify the frontend to impersonate anybody.

Here’s an example how we use both approaches in the same code base:

• Use ic_cdk::api::caller() to get the real caller (e.g. here)
• Pass it into a function (that’s fn my_func(caller: Principal), e.g. here) so that testing becomes easier. Tests are here, but none use different callers right now I think.