Get required fields from Document in mongoengine?

Question

I want to be able to get a list or some sort of set of fields that are required by the document i've created. For instance, here is my document:

nickName        = StringField(required=True)
password        = StringField(required=True)
firstName       = StringField()
lastName        = StringField()
joinDate        = DateTimeField(required=True)
lastVisited     = DateTimeField(required=True)
subscriptions   = DictField(field=ObjectIdField())
isActivated     = BooleanField(default=True)
profileImage    = FileField()
isModerator     = BooleanField(default=False)
description     = StringField()
location        = GeoPointField()
email           = EmailField()
settings        = DictField()

^From this document I should receive:

["nickName","password","joinDate","lastVisited"]

as results for being required fields. Is this possible? If so, how can I achieve the desired result.

Thanks in advance!

Answer 1

This is what I wrote to generate a dict of all the fields and their nested types.

from mongoengine.fields import (
    IntField,
    BooleanField,
    StringField,
    DateTimeField,
    DecimalField,
    FloatField,
    LongField,
    ListField,
    EmbeddedDocumentField,
    ReferenceField,
)

__input_types = {
    IntField,
    BooleanField,
    StringField,
    DateTimeField,
    DecimalField,
    FloatField,
    LongField,
}

__input_num_types = {
    IntField,
    BooleanField,
    DecimalField,
    FloatField,
    LongField,
}

def list_schema(m):
    """list all the field in the model
    and in the nested models"""
    sdict = {}
    for k, v in m._fields.iteritems():
        if k == '_cls':
            continue

        ftype = type(v)
        if ftype in __input_types:
            sdict[k] = {
                'default': v.default if v.default else '',
                'is_num': ftype in __input_num_types,
                'required': v.required,
            }
        elif ftype == ListField:
            seqtype = v.field
            if seqtype in __input_types:
                sdict[k] = [{
                    'default': v.default() if v.default else '',
                    'is_num': seqtype in __input_num_types,
                    'required': v.required,
                }]
            else:
                sdict[k] = [list_schema(seqtype.document_type)]
        else:
            sdict[k] = list_schema(v.document_type)
    return sdict