mongo_aggregation

Python MongoDB Aggregation ORM class.

Installation

pip install mongo_aggregation

Usage examples

import pymongo
from datetime import datetime
from dateutil.relativedelta import relativedelta
from mongo_aggregation import MongoAggregation

# Usual pymongo connection
client = pymongo.MongoClient('mongodb://localhost:27017/test')
db = client.get_database()
today = datetime.now()
yesterday = today - relativedelta(days=1)

# Compose the pipeline
pipeline = MongoAggregation(collection=db.action)
pipeline.match(
    {'date': {'$gte': yesterday, '$lt': today}},
    completed=True,
    _cls={'$in': [
        'Action.Order', 'Action.StorageIncome', 'Action.StorageCancellation', 'Action.StorageMovementOutcome'
    ]},
).smart_project(
    'transactions.amount,_cls', '_id'
).append([
    {'$project': {
        '_cls': 1,
        'date': 1,
        'transactions.amount': 1,
        'transactions.cashbox': 1,
    }},
]).project(
    {'transactions.amount': 1, 'transactions.cashbox': 1}, _cls=1, date=1
).project(
    transactions=1, _cls=1, date=1
)
# Run it
cursor = pipeline.aggregate()

# Iterate over result
for doc in cursor:
    print(doc)
    break

Methods description

• $sort

pipeline.sort('-doctor')
# {'$sort': {'doctor': -1}}

pipeline.sort({'doctor': 1})
# {'$sort': {'doctor': 1}}

pipeline.sort('doctor', '-patient')
# [{'$sort': {'doctor': 1}}, {'$sort': {'-patient': 1}}]

• order_by is an alias to sort.

pipeline.order_by('-doctor')
# {'$sort': {'doctor': -1}}

• $replaceRoot

pipeline.replace_root('doctor')
# {'$replaceRoot': {'newRoot': '$doctor'}}

• $count

Returns count. Does not add stage.

pipeline.count()
2

Response as list

By default aggregate returns cursor. If you want it to return a list of documents use as_list argument:

data = pipeline.aggregate(as_list=True)

Patterns module

Provides operators and some other patterns in python functions way.

Imports:

from mongo_aggregation.patterns import regex

• $and

and_({'a': True}, b=True, c=True)
# {'$and': [{'a': True}, {'b': True}, {'c': True}]}

• $or

or_({'a': True}, b=True, c=True)
# {'$or': [{'a': True}, {'b': True}, {'c': True}]}

• $regex

regex('name', i=True)
# {'$regex': 'name', '$options': 'i'}

Aggregation patterns module

Provides aggregation operators and some other patterns in python functions way.

Imports:

from mongo_aggregation.aggr_patterns import merge_objects

• $ifNull
  There are two variations:

if_null('$doctor', {})
{'$ifNull': ['$doctor', {}]}

ifNull('$doctor', '')
{'$ifNull': ['$doctor', '']}

Function looks after dollar prefix, so you can skip it:

if_null('doctor', {})
{'$ifNull': ['$doctor', {}]}

• $in
  There are two variations:

in_('doctor', 'doctors')
{'$in': ['$doctor', '$doctors']}

• $mergeObjects

merge_objects('$doctor', first_name='John', last_name='Doe')
# {'$mergeObjects': ['$doctor', {'first_name': 'John', 'last_name': 'Doe'}]}

Others

• obj function
  Returns dictionary with specified fields as keys and values. For better understanding see usage examples below.

>>> obj('name,description')
{'name': '$name', 'description': '$description'}

>>> obj('name', 'description')
{'name': '$name', 'description': '$description'}

>>> obj('name,description', id='$code')
{'name': '$name', 'description': '$description', 'id': '$code'} 

Changelog

1.0.10 (2021-01-19)

• Fixed bug with multiple operators for a field in a _convert_names_with_underlines_to_dots pattern.

1.0.9 (2020-12-24)

• Added in_ aggregation pattern.

1.0.8 (2020-12-11)

• Added and_, and_nor, and_or methods to MongoMatchFilter.

1.0.7 (2020-09-19)

• Small fix.

1.0.6 (2020-11-19)

• Added if_null pattern.
• Removed get_count method. count now returns count and does not add count stage.
• Added obj pattern.

1.0.5 (2020-09-25)

• Added order_by method.

1.0.4 (2020-09-25)

• Bug fixes.

1.0.3 (2020-09-01)

• .sort now supports -email sorting format (direction and field name by string).
• Added .replace_root method.
• Added or_ and and_ logical operators. _and is deprecated now.
• Added regex operator pattern.
• Added merge_objects aggregation operator (./aggr_patterns).

1.0.2 (2020-09-01)

• Added $addFields and $set stages.
• Added $filter operator.