Converting Document fields before returning - rest

Question

I'm building a flask project with mongoengine, and I'm struggling to find a good way to convert some fields before returning a document.
I have this as a document:
class Effects(Document):
name = StringField(unique=True, required=True,
min_length=2, max_length=20, validation=name_is_not_taken)
parameters = EmbeddedDocumentListField(Parameter)
parameterKeys = ListField(StringField(required=True, null=True))
created_at = DateTimeField(default=datetime.now)
created_by = StringField(required=True)
effect_link = StringField(required=True)
description = StringField(required=False)
file = FileField(required=False)
When calling a route to get all of those documents (Effect.objects().all), here is what it looks like
{
"_id": {
"$oid": "62138365ae75aceb4c4f3466"
},
"created_at": {
"$date": 1645449589917
},
"effect_link": "put link here",
"name": "gain",
"parameters": {
"Gain": {
"default_value": 0.5,
"range_end": 1.0,
"range_start": 0.0,
"type": "range",
"unit": "float"
}
}
},
My question is, is there a way to consistently convert the _id and created_at from objects to string everytime I return one or more Effects document so the result looks like this:
{
"id": "62138365ae75aceb4c4f3466",
"created_at": "62138365ae75aceb4c4f3466",
"effect_link": "put link here",
"name": "gain",
"parameters": {
"Gain": {
"default_value": 0.5,
"range_end": 1.0,
"range_start": 0.0,
"type": "range",
"unit": "float"
}
}
}
I've seen that you can use aggregate in order to do operations like this but I'm not sure if it is the best way.
Thanks a lot !

Answer 1

If I am not mistaken mongoengine does not supports serialization. I had few applications written in mongoengine. One of them used django so I was using django-rest-framework-mongoengine, it may not be relevant to your project, because you are using flask. Alternative would be to use mongoengine_serialize, it only supports ObjectIds and datetimes, so I think it will be useful for your project.