criteria-pattern 3.11.0

The Criteria Pattern is a Python package that simplifies and standardizes criteria based filtering, validation and selection.

🤏🏻 Criteria Pattern

The Criteria Pattern is a Python 🐍 package that simplifies and standardizes criteria based filtering 🤏🏻, validation and selection. This package provides a set of prebuilt 👷🏻 objects and utilities that you can drop into your existing projects and not have to implement yourself.

These utilities 🛠️ are useful when you need complex filtering logic. It also enforces 👮🏻 best practices so all your filtering processes follow a uniform standard.

Easy to install and integrate, this is a must have for any Python developer looking to simplify their workflow, enforce design patterns and use the full power of modern ORMs and SQL 🗄️ in their projects 🚀.

Table of Contents

• 📥 Installation
• 📚 Documentation
• 💻 Utilization
  • 🔄 Available Converters
  • 🔎 Simple URL Query Examples
  • 🎯 Real-Life Case: Multi-tenant User Search Service
• 🤝 Contributing
• 🔑 License

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📥 Installation

You can install Criteria Pattern using pip:

pip install criteria-pattern

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📚 Documentation

This project's documentation is powered by DeepWiki, which provides a comprehensive overview of the Criteria Pattern and its usage.

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💻 Utilization

from criteria_pattern import Criteria, Filter, Operator
from criteria_pattern.converters import CriteriaToPostgresqlConverter

is_adult = Criteria(filters=[Filter(field='age', operator=Operator.GREATER_OR_EQUAL, value=18)])
email_is_gmail = Criteria(filters=[Filter(field='email', operator=Operator.ENDS_WITH, value='@gmail.com')])
email_is_yahoo = Criteria(filters=[Filter(field='email', operator=Operator.ENDS_WITH, value='@yahoo.com')])

query, parameters = CriteriaToPostgresqlConverter.convert(criteria=is_adult & (email_is_gmail | email_is_yahoo), table='user')
print(query)
print(parameters)
# >>> SELECT * FROM user WHERE (age >= %(parameter_0)s AND (email LIKE '%%' || %(parameter_1)s OR email LIKE '%%' || %(parameter_2)s));
# >>> {'parameter_0': 18, 'parameter_1': '@gmail.com', 'parameter_2': '@yahoo.com'}

🔄 Available Converters

The package includes converters for SQL generation and request parsing:

• criteria_pattern.converters.CriteriaToPostgresqlConverter: Converts a Criteria object into PostgreSQL SQL + parameters.
• criteria_pattern.converters.CriteriaToMysqlConverter: Converts a Criteria object into MySQL SQL + parameters.
• criteria_pattern.converters.CriteriaToMariadbConverter: Converts a Criteria object into MariaDB SQL + parameters.
• criteria_pattern.converters.CriteriaToSqliteConverter: Converts a Criteria object into SQLite SQL + parameters.
• criteria_pattern.converters.SimpleUrlToCriteriaConverter: Parses simple public URL query parameters into a Criteria object.
• criteria_pattern.converters.UrlToCriteriaConverter: Parses URL query parameters into a Criteria object.
• criteria_pattern.converters.BodyToCriteriaConverter: Parses decoded request bodies into a Criteria object.

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🎯 Real-Life Case: Multi-tenant User Search Service

Imagine an admin dashboard where each request must:

1. Always restrict results to the current tenant.
2. Optionally filter active users.
3. Search only users with company emails.
4. Sort by newest users first.

With Criteria Pattern, each concern is a small reusable criteria object. You combine them using & and |, then convert once to SQL:

from criteria_pattern import Criteria, Direction, Filter, Operator, Order
from criteria_pattern.converters import CriteriaToPostgresqlConverter


class UserSearchService:
    def __init__(self, tenant_id: str) -> None:
        self.tenant_id = tenant_id

    def build_query(self, *, only_active: bool, corporate_domain: str) -> tuple[str, dict[str, object]]:
        tenant_scope = Criteria(filters=[Filter(field='tenant_id', operator=Operator.EQUAL, value=self.tenant_id)])
        active_scope = Criteria(filters=[Filter(field='is_active', operator=Operator.EQUAL, value=True)])
        email_scope = Criteria(filters=[Filter(field='email', operator=Operator.ENDS_WITH, value=corporate_domain)])
        sort_scope = Criteria(orders=[Order(field='created_at', direction=Direction.DESC)])

        criteria = tenant_scope & email_scope & sort_scope
        if only_active:
            criteria = criteria & active_scope

        return CriteriaToPostgresqlConverter.convert(criteria=criteria, table='users')


service = UserSearchService(tenant_id='tenant_123')
query, parameters = service.build_query(only_active=True, corporate_domain='@acme.com')

print(query)
print(parameters)

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🔎 Simple URL Query Examples

Use SimpleUrlToCriteriaConverter when you want a compact public query format where each parameter becomes one AND filter. Plain parameters use equality, and suffixes map to operators.

from criteria_pattern.converters import SimpleUrlToCriteriaConverter


criteria = SimpleUrlToCriteriaConverter.convert(
    url='https://api.example.com/users?name=Doe&age_gte=18&page_size=20&page_number=1'
)

print(criteria.filters[0].field, criteria.filters[0].operator, criteria.filters[0].value)
# >>> name EQUAL Doe

print(criteria.filters[1].field, criteria.filters[1].operator, criteria.filters[1].value)
# >>> age GREATER_OR_EQUAL 18

print(criteria.page_size, criteria.page_number)
# >>> 20 1

Common suffixes:

URL parameter	Parsed filter
name=Doe	Filter(field='name', operator=Operator.EQUAL, value='Doe')
name_eq=Doe	Filter(field='name', operator=Operator.EQUAL, value='Doe')
status_ne=DELETED	Filter(field='status', operator=Operator.NOT_EQUAL, value='DELETED')
price_gt=10	Filter(field='price', operator=Operator.GREATER, value=10)
price_gte=10	Filter(field='price', operator=Operator.GREATER_OR_EQUAL, value=10)
price_lt=100	Filter(field='price', operator=Operator.LESS, value=100)
price_lte=100	Filter(field='price', operator=Operator.LESS_OR_EQUAL, value=100)
email_contains=gmail.com	Filter(field='email', operator=Operator.CONTAINS, value='gmail.com')
name_starts_with=Ad	Filter(field='name', operator=Operator.STARTS_WITH, value='Ad')
email_ends_with=.com	Filter(field='email', operator=Operator.ENDS_WITH, value='.com')
status_in=ACTIVE&status_in=PENDING	Filter(field='status', operator=Operator.IN, value=['ACTIVE', 'PENDING'])
status_not_in=DELETED	Filter(field='status', operator=Operator.NOT_IN, value=['DELETED'])
deleted_at_is_null=true	Filter(field='deleted_at', operator=Operator.IS_NULL, value=None)
deleted_at_is_not_null=true	Filter(field='deleted_at', operator=Operator.IS_NOT_NULL, value=None)

Comma-separated values are also supported for list operators:

criteria = SimpleUrlToCriteriaConverter.convert(
    url='https://api.example.com/users?status_in=ACTIVE,PENDING,BLOCKED'
)

print(criteria.filters[0].value)
# >>> ['ACTIVE', 'PENDING', 'BLOCKED']

You can map public field names to internal field names:

criteria = SimpleUrlToCriteriaConverter.convert(
    url='https://api.example.com/users?full_name_contains=Doe',
    fields_mapping={'full_name': 'name'},
)

print(criteria.filters[0].field, criteria.filters[0].operator, criteria.filters[0].value)
# >>> name CONTAINS Doe

You can also extend or override URL suffixes:

criteria = SimpleUrlToCriteriaConverter.convert(
    url='https://api.example.com/users?created_at_after=2026-05-18',
    suffix_operator_mapping={'after': Operator.GREATER},
)

print(criteria.filters[0].field, criteria.filters[0].operator, criteria.filters[0].value)
# >>> created_at GREATER 2026-05-18

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🤝 Contributing

We love community help! Before you open an issue or pull request, please read:

• 🤝 How to Contribute
• 🧭 Code of Conduct
• 🔐 Security Policy

Thank you for helping make 🤏🏻 Criteria Pattern package awesome! 🌟

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🔑 License

This project is licensed under the terms of the MIT license.

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