Update a MongoEngine document using a python dict?

Question

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

For example:

class Pets(EmbeddedDocument):
    name = StringField()

class Person(Do         


        

Answer 1

Here is a function to update documents with EmbeddedDocuments. It is based upon @rednaw's solution, though accounts for EmbeddedDocuments having EmbeddedDocuments.

from mongoengine.fields import *

def field_value(field, value):
  ''' 
  Converts a supplied value to the type required by the field.
  If the field requires a EmbeddedDocument the EmbeddedDocument
  is created and updated using the supplied data.
  '''
  if field.__class__ in (ListField, SortedListField):
    # return a list of the field values 
    return [
      field_value(field.field, item) 
      for item in value]

  elif field.__class__ in (
    EmbeddedDocumentField,
    GenericEmbeddedDocumentField,
    ReferenceField,
    GenericReferenceField):

    embedded_doc = field.document_type()
    update_document(embedded_doc, value)
    return embedded_doc
  else:
    return value


def update_document(doc, data):
  ''' Update an document to match the supplied dictionary.
  '''
  for key, value in data.iteritems():

    if hasattr(doc, key):
        value = field_value(doc._fields[key], value)
        setattr(doc, key, value)
    else:
        # handle invalid key
        pass

  return doc

The key here is the field_value method updating an embedded document rather than instantiating it with the data.

Usage Example :

class Pets(EmbeddedDocument):
    name = StringField()

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

class Group(Document):
    name = StringField()
    members = ListField(EmbeddedDocumentField(Person))

g = Group()

update_document(g, {
  'name': 'Coding Buddies',
  'members': [
    {
      'name': 'Dawson',
      'address': 'Somewhere in Nova Scotia',
      'pets': [
        {
          'name': 'Sparkles'
        }
      ]
    },
    {
      'name': 'rednaw',
      'address': 'Not too sure?',
      'pets': [
        {
          'name': 'Fluffy'
        }
      ]
    }
  ]
})

FYI That's actually my cat's name.

EDIT : typo in variable names.