Getting actor (class) from Principal

[Gekctek]

I currently get a principals from actor classes from the following code:

let a = await ActorClass.ActorClass();
let p : Principal = Principal.fromActor(a); // Get principal from actor

Later, using that principal i want to make a connection back to the actor class. What is the syntax for doing so in Motoko?

let a = ActorClass.ActorClass(p); ??????

let a = ActorClass.ActorClass.fromPrincipal(p); ?????

[paulyoung]

I think this will help:

Calling another canister's methods

You can also use a canister id to access a previously deployed canister: canister1/main.mo actor { public func main(canisterId: Text) : async Nat { let canister2 = actor(canisterId): actor { getValue: () -> async Nat }; return await canister2.getValue(); }; }; Where canister2’s id from the previous example can be passed in, similar to: $ dfx canister call canister1 main "ic:6EF4FCAD1FD36EB654" --type string Note the type signature actor { getValue: () -> async Nat } …

[rossberg]

Just to be sure, you should never be doing that, unless you received the principal id from outside your program. This approach ruins all type safety.

If a program creates an actor, and later needs to call it, then it should simply store the actor reference, not just its principal id.