Is it possible to have custom filtering logic on subscription in AWS AppSync?
As I know, current behavior is: e.g. my schema is like the following
type Mutation {
createEvent(userId: ID!, event: Event!): Event!
}
type Subscription {
onEvent(userId: ID!): Event!
@aws_subscribe(mutations: ["createEvent"])
}
Current behavior of AppSync is, when I trigger createEvent, AppSync promise that the subscriber of Subscription receive the Event if the userId are equal. i.e. the filtering logic of AppSync is sth like
if (Muatation.userId == Subscription.userId) {
// forward to subscriber
}
But what if I want different filtering logic? For example, I want to subscribe all other events except those triggered by me? i.e.
if (Muatation.userId != Subscription.userId) {
// forward to subscriber
}
So, is it possible to have custom filtering logic in AppSync?
Currently, this use case is not supported by AppSync.
Adding custom filtering may be considered in the future.
After having a look at possible filtering method here - appsync-doc
It doesn't seem possible
only thing you can do is, add a small logic in your client to detect if the Subscription is yours by comparing userid's.