MongoEngine

About

MongoEngine is a Python Object-Document Mapper for working with MongoDB. Documentation is available at https://mongoengine-odm.readthedocs.io - there is currently a tutorial, a user guide, and an API reference.

Supported MongoDB Versions

MongoEngine is currently tested against MongoDB v3.4, v3.6 and v4.0. Future versions should be supported as well, but aren't actively tested at the moment. Make sure to open an issue or submit a pull request if you experience any problems with MongoDB version > 4.0.

Installation

We recommend the use of virtualenv and of pip. You can then use python -m pip install -U mongoengine. You may also have setuptools and thus you can use easy_install -U mongoengine. Another option is pipenv. You can then use pipenv install mongoengine to both create the virtual environment and install the package. Otherwise, you can download the source from GitHub and run python setup.py install.

The support for Python2 was dropped with MongoEngine 0.20.0

Dependencies

All of the dependencies can easily be installed via python -m pip. At the very least, you'll need these two packages to use MongoEngine:

• pymongo>=3.4

If you utilize a DateTimeField, you might also use a more flexible date parser:

• dateutil>=2.1.0

If you need to use an ImageField or ImageGridFsProxy:

• Pillow>=2.0.0

If you need to use signals:

• blinker>=1.3

Examples

Some simple examples of what MongoEngine code looks like:

from mongoengine import *
connect('mydb')

class BlogPost(Document):
    title = StringField(required=True, max_length=200)
    posted = DateTimeField(default=datetime.datetime.utcnow)
    tags = ListField(StringField(max_length=50))
    meta = {'allow_inheritance': True}

class TextPost(BlogPost):
    content = StringField(required=True)

class LinkPost(BlogPost):
    url = StringField(required=True)

# Create a text-based post
>>> post1 = TextPost(title='Using MongoEngine', content='See the tutorial')
>>> post1.tags = ['mongodb', 'mongoengine']
>>> post1.save()

# Create a link-based post
>>> post2 = LinkPost(title='MongoEngine Docs', url='hmarr.com/mongoengine')
>>> post2.tags = ['mongoengine', 'documentation']
>>> post2.save()

# Iterate over all posts using the BlogPost superclass
>>> for post in BlogPost.objects:
...     print('===', post.title, '===')
...     if isinstance(post, TextPost):
...         print(post.content)
...     elif isinstance(post, LinkPost):
...         print('Link:', post.url)
...

# Count all blog posts and its subtypes
>>> BlogPost.objects.count()
2
>>> TextPost.objects.count()
1
>>> LinkPost.objects.count()
1

# Count tagged posts
>>> BlogPost.objects(tags='mongoengine').count()
2
>>> BlogPost.objects(tags='mongodb').count()
1

Tests

To run the test suite, ensure you are running a local instance of MongoDB on the standard port and have pytest installed. Then, run python setup.py test or simply pytest.

To run the test suite on every supported Python and PyMongo version, you can use tox. You'll need to make sure you have each supported Python version installed in your environment and then:

# Install tox
$ python -m pip install tox
# Run the test suites
$ tox

If you wish to run a subset of tests, use the pytest convention:

# Run all the tests in a particular test file
$ pytest tests/fields/test_fields.py
# Run only particular test class in that file
$ pytest tests/fields/test_fields.py::TestField

Community

• MongoEngine Users mailing list
• MongoEngine Developers mailing list

Contributing

We welcome contributions! See the Contribution guidelines