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

We recommend the use of virtualenv and of pip. You can then use pip install -U mongoengine. You may also have setuptools and thus you can use easy_install -U mongoengine. Otherwise, you can download the source from GitHub and run python setup.py install.

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

• pymongo>=2.7.1
• six>=1.10.0

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 want to generate the documentation (e.g. to contribute to it):

• sphinx

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
...     print
...

# 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

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

To run the test suite on every supported Python version and every supported PyMongo version, you can use tox. tox and each supported Python version should be installed in your environment:

# Install tox
$ pip install tox
# Run the test suites
$ tox

If you wish to run one single or selected tests, use the nosetest convention. It will find the folder, eventually the file, go to the TestClass specified after the colon and eventually right to the single test. Also use the -s argument if you want to print out whatever or access pdb while testing.

$ python setup.py nosetests --tests tests/fields/fields.py:FieldTest.test_cls_field -s

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