Loopback 3 get relation from embedded model - mongodb

Question

I'm using loopback 3 to build a backend with mongoDB.
So i have 3 models: Object, Attachment and AwsS3.
Object has a relation Embeds2Many to Attachment.
Attachment has a relation Many2One to AwsS3.
Objects look like that in mongoDB
[
{
"fieldA": "valueA1",
"attachments": [
{
"id": 1,
"awsS3Id": "1234"
},
{
"id": 2,
"awsS3Id": "1235"
}
]
},
{
"fieldA": "valueA2",
"attachments": [
{
"id": 4,
"awsS3Id": "1236"
},
{
"id": 5,
"awsS3Id": "1237"
}
]
}
]
AwsS3 looks like that in mongoDB
[
{
"id": "1",
"url": "abc.com/1"
},
{
"id": "2",
"url": "abc.com/2"
}
]
The question is: how can i get Objects included Attachment and AwsS3.url over the RestAPI?
I have try with the include and scope filter. But it didn't work. It look like, that this function is not implemented in loopback3, right? Here is what i tried over the GET request:
{
"filter": {
"include": {
"relation": "Attachment",
"scope": {
"include": {
"relation": "awsS3",
}
}
}
}
}
With this request i only got the Objects with Attachments without anything from AwsS3.
UPDATE for the relation definitons
The relation from Object to Attachment:
"Attachment": {
"type": "embedsMany",
"model": "Attachment",
"property": "attachments",
"options": {
"validate": true,
"forceId": false
}
},
The relation from Attachment to AwsS3
in attachment.json
"relations": {
"awsS3": {
"type": "belongsTo",
"model": "AwsS3",
"foreignKey": ""
}
}
in AwsS3.json
"relations": {
"attachments": {
"type": "hasMany",
"model": "Attachment",
"foreignKey": ""
}
}

Answer 1

Try this filter:
{ "filter": { "include": ["awsS3", "attachments"]}}}}