使用python dict更新MongoEngine文档? [英] Update a MongoEngine document using a python dict?

问题描述

是否可以使用python字典更新MongoEngine文档?

Is it possible to update a MongoEngine document using a python dict?

例如:

class Pets(EmbeddedDocument):
    name = StringField()

class Person(Document):
    name = StringField()
    address = StringField()
    pets = ListField(EmbeddedDocumentField(Pets))

p = Person()
p.update_with_dict({
    "name": "Hank",
    "address": "Far away",
    "pets": [
        {
            "name": "Scooter"
        }
    ]
})

推荐答案

好吧，我为此做了一个函数.

Ok I just made a function for it.

您将其称为update_document(document, data_dict).它将循环遍历data_dict的各项，并使用data_dict的键获取字段实例.然后它将调用field_value(field, value)，其中field是字段实例. field_value()将使用field.__class__检查字段的类型，并基于该返回值返回MongoEngine期望的值.例如，可以直接返回普通StringField的值，但是对于EmbeddedDocumentField，需要创建该嵌入式文档类型的实例.它还对列表字段中的项目执行此操作.

You call it like update_document(document, data_dict). It will loop through the items of data_dict and get the field instance using the key of the data_dict. It will then call field_value(field, value) where field is the field instance. field_value() will check the type of field using field.__class__ and based on that return a value that MongoEngine would expect. For example, the value of a normal StringField can just be returned as is, but for an EmbeddedDocumentField, an instance of that embedded document type needs to be created. It also does this trick for the items in lists fields.

from mongoengine import fields


def update_document(document, data_dict):

    def field_value(field, value):

        if field.__class__ in (fields.ListField, fields.SortedListField):
            return [
                field_value(field.field, item)
                for item in value
            ]
        if field.__class__ in (
            fields.EmbeddedDocumentField,
            fields.GenericEmbeddedDocumentField,
            fields.ReferenceField,
            fields.GenericReferenceField
        ):
            return field.document_type(**value)
        else:
            return value

    [setattr(
        document, key,
        field_value(document._fields[key], value)
    ) for key, value in data_dict.items()]

    return document

用法:

class Pets(EmbeddedDocument):
    name = StringField()

class Person(Document):
    name = StringField()
    address = StringField()
    pets = ListField(EmbeddedDocumentField(Pets))

person = Person()

data = {
    "name": "Hank",
    "address": "Far away",
    "pets": [
        {
            "name": "Scooter"
        }
    ]
}

update_document(person, data)

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