CODEWITHSUNDEEP
pythonpython-3.xdatabasemongodbmongoengine
Gentatsu
Gentatsu

Reputation: 717

Computed field in mongoengine from a function

To avoid computing and setting fields explicitly on a mongoengine Document, I'd like to have it as a computed field. Is this currently possible?

Here's a MWE of what I'm expecting:

class Task(Document):
    meta = {"collection": "tasks"}

    @property
    def get_values_count(self):
        return len(self.values)

    dateAdded = DateTimeField()
    dateStarted = DateTimeField(default=datetime.utcnow())
    values = ListField(IntField())
    values_count = IntField(default=get_values_count) # Either this, normal class functions not supported by Documents
    # values_count = IntField(default = lambda : len(self.values)) //Or this (this won't compile)

Any way of achieving something like this?

Upvotes: 0

Views: 672

Answers (1)

AlexisG
AlexisG

Reputation: 2484

If I correctly understand, you don't want to store values_count in your database. So you can just use a @property

class Task(Document):
    meta = {"collection": "tasks"}

    @property
    def values_count(self):
        return len(self.values)

    dateAdded = DateTimeField()
    dateStarted = DateTimeField(default=datetime.utcnow())
    values = ListField(IntField())

Upvotes: 1

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