AWS Amplify AppSync Subscription not working correctly - ionic-framework

Question

I wrote a small application that subscribes to DB changes using AWS Amplify CLI / AppSync. All amplify api calls work perfectly (mutations, queries) but unfortunately the observer does not receive events. I can see that the MQTT socket receives periodically binaries but I can't obtain changed objects.
I configured Amplify for amplify use. I can see in the debugger that the AppSyncProvider has been initisalised. Also tried API and PubSub but makes no difference.
const awsmobile = {
"aws_appsync_graphqlEndpoint": "https://[...].appsync-api.[...]/graphql",
"aws_appsync_region": "[...]",
"aws_appsync_authenticationType": "AMAZON_COGNITO_USER_POOLS",
};
Amplify.configure(awsmobile);
ngOnInit()
{
try {
this.apiService.OnUpdateA.subscribe(
{
next: (x) => {[...]},
error: (e) => {[...]},
complete: () => {[...]}
});
}
catch (error) {[...] }
}
***Schema***
type A
#model
#auth(rules: [
{allow: owner},
{allow: groups, groups: ["A"], operations: [create, update, read]},
{allow: groups, groups: ["B"], operations: [read]},
])
{
id: ID!
entry: AnotherType! #connection(name: "AnotherConnection")
[...]
}
OnUpdateAListener: Observable<
OnUpdateASubscription
> = API.graphql(
graphqlOperation(
`subscription OnUpdateA($owner: String) {
onUpdateA(owner: $owner) {
__typename
id
owner
[...]
}
}`
)
) as Observable<OnUpdateASubscription>;
Anyone for any ideas?
**Logs:**
{mqttConnections: Array(1), newSubscriptions: {…}, provider: Symbol(INTERNAL_AWS_APPSYNC_PUBSUB_PROVIDER)}
mqttConnections: Array(1)
0: {url: "wss://[...]-ats.iot.[...].amazonaws…[...]%3D%3D", topics: Array(2), client: "[...]"}
length: 1
__proto__: Array(0)
newSubscriptions:
onUpdate:
expireTime: 1573313050000
topic: "[....]/22tmaezjv5555h4o7yreu24f7u/onUpdate/1cd033bad555ba55555a20690d3e04e901145776d3b8d8ac95a0aea447b273c3"
__proto__: Object
__proto__: Object
provider: Symbol(INTERNAL_AWS_APPSYNC_PUBSUB_PROVIDER)
__proto__: Object
However, not sure whether it is suspicious that the subscription Object has no queue?
Subscription {_observer: {…}, _queue: undefined, _state: "ready", _cleanup: ƒ}
_cleanup: ƒ ()
_observer:
next: (x) => {…}
__proto__: Object
_queue: ***undefined***
_state: "ready"
closed: (...)
__proto__: Object
Many thanks in advance.

Answer 1

For those who are experiencing the same behaviour. It was due to the fact that I had the owner in the auth section of the schema. Deleted the {allow: owner}, part and the subscriptions started to work immediately.

Answer 2

here is a working example of AWS Amplify Subscriptions:
import Amplify from 'aws-amplify';
import API from '#aws-amplify/api';
import PubSub from '#aws-amplify/pubsub';
import awsconfig from './aws-exports';
Amplify.configure(awsconfig);
API.configure(awsconfig);
PubSub.configure(awsconfig);
// put above in root
// below is example
import { API, graphqlOperation } from 'aws-amplify';
var onAddNote = `subscription OnCreateNote {
onCreateNote {
id
patient {
id
organization {
id
}
}
}
}
`;
listenForNoteAdd() {
return API.graphql(graphqlOperation(onAddNote) ).subscribe({next: (noteData) => {
console.log("new note so reload consider reload")
let note = noteData.value.data.onCreateNote
console.log(JSON.stringify(note))
// now that you have indication of something happening
// do what you must next
}})
}

Answer 3

I had the same problem with GraphQL. Thing is: we have to return Owner in mutation response in order to let Subscription know to whom to send this event.
removing {allow: owner} did worked for me but thats not the right way since we require it in order to have owner based access to data.
so the correct way i found is:
if subscription is:
subscription MySubscription {
onCreateuser(owner: "$userName") {
id
name
number
}
}
mutation should be:
mutation MyMutation {
createUser(input: {name: "xyz", id: "user123", number: "1234567890"}) {
id
name
number
owner
}
}
we must return owner in mutation's response in order to get the subscription to that event and all other properties as same as mutation response.

Answer 4

For those coming here experiencing this error, do not delete {allow: owner}. Allow owner ensures only a user authenticated with Cognito User Pool can run queries, mutations, etc.
It looks like the OP is using amplify codegen to generate his API service, and if you look the listener has param for owner. It's optional, but if your #auth is {allow: owner} it is required.
Additional note: Not sure if he is using the correct owner field stored in his datastore or not. If there is not already an owner field created (or a different field specified), it will create one with a unique uuid. So he could be passing the incorrect owner or none at all.
Run a simple call to get the owner...
export const GetOwner = async (id: string): Promise<GetOwnerQuery> => {
const statement = `query GetAppData($id: ID!) {
getAppData(id: $id) {
owner
}
}`;
const gqlAPIServiceArguments: any = {
id,
};
const response = (await API.graphql(graphqlOperation(statement, gqlAPIServiceArguments))) as any;
return <GetOwnerQuery>response.data.getAppData;
};
...and pass that in your subscription.
const { owner } = await GetOwner(id);
if (owner) {
this.apiUpdateListener$ = this.api.OnUpdateAppDataListener(owner).subscribe((data) => {
console.log('api update listener ===> ', data);
});
}