mongomodels

A simple ODM for MongoDB

Installation

pip install mongomodels

Usage

Define your base model to refer to the mongo instance

from mongomodels.db import MongoDatabaseBackend
from mongomodels.models import ValidatingStruct

class BaseModel(ValidatingStruct):
    __DOCUMENT_DB__ = MongoDatabaseBackend('localhost', 'test_database')

For development purposes you can use an In-Memory document database

from mongomodels.db import MemoryDatabaseBackend
from mongomodels.models import ValidatingStruct

class BaseModel(ValidatingStruct):
    __DOCUMENT_DB__ = MemoryDatabaseBackend()

Define your models

Each model must have a document name, so that the it refers to the proper collection on MongoDB. By default it takes the snake_case version of the class.

class MyTestModel(BaseModel): # This would map to __DOCUMENT_NAME__ = 'my_test_model'
    pass
    # Or you could redefine your document name
    # __DOCUMENT_NAME__ = 'test_model'

Create your objects

test_object = MyTestModel(some_attribute='some value')
test_object.save()

Find your objects

MyTestModel.all() # Returns a list with all the objects in the document
MyTestModel.all(some_attribute='some value') # Returns all the objects
                                             # that meet the same attributes

MyTestModel.get() # Returns the first object of the collection
MyTestModel.get(some_attribute='some value') # Returns the first object
                                             # that meets the attributes

Validations

# Let's say we have some Message model that relates to a User and a chat Room

class Message(BaseModel): # Our previously defined BaseModel

    def validate(self):
        self.validate_not_empty('message')
        self.validate_not_empty('user_id')
        self.validate_not_empty('room_id')
        self.validate_existance('user_id', User)
        self.validate_existance('room_id', Room)

        self.validate_field(
                              'message',
                              self.validate_message,
                              'Message too long, max length is 255'
                           )

    def validate_message(self, message):
        return len(message) <= 255

For running validations on our models we have to redefine the method validate, in which we will set all our pre save validations.

validate_not_empty: Validates that our field has any data

validate_existance: Validates that the relationship field matches an object on the relationship model

validate_field: Validates the given field with a custom function, the function should receive only one argument representing the value to validate and should return a boolean. Also, accepts an optional error message.

validate_in: Validates that the given field has a value inside the provided value list.

validate_type: Validates that the given field contains an object of the expected type. Valid Types: Any kind of Struct (models), strings, integers, floats, lists and dictionaries.

dlitvakb / mongomodels