django-deep 0.1.0

Django Enhanced Expression Parser

django-deep

Django library for advanced SQL expressions: subqueries (SUM, COUNT, JsonAgg, ConcatValues), JSON extraction, and dynamic filter parsing.

Features

• DeepManager – Custom manager with subquery helpers (get_sum_sub_query, get_count_sub_query, get_json_agg_sub_query, get_concat_values_sub_query, get_method_from_sub_query) and JsonExtract for JSON fields
• DeepParser – Parses dynamic filter expressions from string parameters (include, exclude, order, distinct) to build Django Q objects
• Subqueries – SumSubquery, CountSubquery, JsonAggSubquery, ConcatValuesSubquery, MethodFromSubquery, ExtractValueSubquery
• JsonExtract – Database-agnostic JSON field extraction (PostgreSQL, MySQL, SQLite, Oracle)
• MemoryQuerySet – In-memory queryset for testing

Installation

pip install django-deep

Quick start

from django.db import models
from django.db.models import OuterRef
from django_deep import DeepManager

class Order(models.Model):
    customer = models.ForeignKey("Customer", on_delete=models.CASCADE)
    total = models.DecimalField(max_digits=10, decimal_places=2)

class Customer(models.Model):
    name = models.CharField(max_length=255)
    objects = DeepManager()

# Annotate with subqueries
Customer.objects.annotate(
    order_count=Customer.objects.get_count_sub_query(
        Order.objects.filter(customer_id=OuterRef("pk"))
    ),
    order_sum=Customer.objects.get_sum_sub_query(
        Order.objects.filter(customer_id=OuterRef("pk")), sum_field="total"
    ),
)

Subqueries

from django.db.models import OuterRef
from django_deep import DeepManager

# SumSubquery
qs.annotate(total=manager.get_sum_sub_query(Order.objects.filter(...), "total"))

# CountSubquery
qs.annotate(cnt=manager.get_count_sub_query(Order.objects.filter(...)))

# JsonAggSubquery (PostgreSQL, MySQL, SQLite, Oracle)
qs.annotate(items=manager.get_json_agg_sub_query(RelatedModel.objects.filter(...)))

JsonExtract

from django_deep.functions import JsonExtract

# Extract from JSONField
Model.objects.annotate(
    value=JsonExtract("metadata", "path__to__field")
)

Dynamic filters (DeepParser)

Parse include/exclude/order from request params:

parser = DeepParser(queryset, params={"i": "field__filter:value", "o": "name"})
compiled = parser.execute(params.get("i"))
if compiled:
    qs = queryset.filter(compiled)
qs = parser.get_queryset()

Development

pip install -e ".[dev]"
pytest
ruff check .
ruff format .

License

GPL-3.0-or-later — see the LICENSE file.