pyrsql 0.0.2

Compiler-oriented RSQL query engine for safe, typed, and extensible Python ORM-backed APIs.

pyrsql

A compiler-oriented RSQL query engine for safe, typed, and extensible filtering, sorting, and pagination in Python APIs.

pyrsql compiles RSQL query strings into ORM-specific statement objects through a language frontend, semantic binder, logical IR, and pluggable backend lowering - making it easy to expose complex query capabilities in your API without coupling to a specific ORM or framework.

Current backends: SQLAlchemy 2.0
Current framework adapters: FastAPI
Planned: Django ORM, SQLModel, Flask

Why pyrsql?

Most API filtering libraries are tightly coupled to one ORM or one framework. pyrsql is built as a compiler pipeline - parsing, semantic analysis, and IR lowering are separate stages. Adding a new ORM backend means implementing one interface (ORM), not rewriting the parser or query language.

• ORM-neutral core - Query, Sort, PageRequest have zero ORM dependencies
• Pluggable backends - implement compile_query / compile_sort / compile_page_request for any ORM
• Pluggable framework adapters - FastAPI today, Flask/Django tomorrow
• Custom operators - define your own RSQL operators with per-ORM lowering
• Field policies - whitelist, blacklist, aliases at global and per-model level
• Type-safe - strict mypy, Google-style docstrings, immutable value objects

Quickstart

pip install pyrsql[sqlalchemy]

import pyrsql
from sqlalchemy import select
from pyrsql.orms.sqlalchemy import SQLAlchemyORM

orm = SQLAlchemyORM()
stmt = select(User)

# Filter: name equals "demo", company name contains "acme"
stmt = pyrsql.parse("name==demo;company.name==acme*").apply(stmt, User, orm=orm)

# Sort: by name ascending, then company name descending
stmt = pyrsql.Sort.parse("name,asc;company.name,desc").apply(stmt, User, orm=orm)

# Paginate: page 0, 25 items per page
stmt = pyrsql.PageRequest.of(0, 25).apply(stmt, User, orm=orm)

Features

Query (filter)

• 20+ built-in operators: ==, !=, =gt=, =ge=, =lt=, =le=, =in=, =out=, =like=, =ilike=, =bt=, =na=, =nn=, etc.
• Logical composition: ; (AND), , (OR)
• Grouping with parentheses
• Wildcard matching (*demo*) and case-insensitive markers (^demo)
• Strict equality mode (literal * and ^)
• Configurable LIKE escape character
• SELECT DISTINCT support
• Configurable parser limits (query length, depth, argument count)

Sort

• Multi-field: name,asc;company.name,desc,ic
• Ignore-case modifier (ic)
• Function selectors: @upper[name],asc

Pagination

• Page-number + page-size API: PageRequest.of(0, 25)
• Offset + limit API: PageRequest.from_offset(offset=50, limit=25)
• Configurable max page size

Field Mapping & Access Control

• Aliases: field_mapping={"username": "user.name"}
• Whitelist/blacklist: field_whitelist, field_blacklist
• Per-model policies: model_field_mapping, model_field_whitelist, model_field_blacklist

Custom Predicates

Define custom operators with ORM-specific lowering:

from pyrsql import CustomPredicateDefinition, QueryOptions
from pyrsql.parsing.operators import ComparisonOperator

all_match = ComparisonOperator(name="all_match", spellings=("=all=",), ...)
options = QueryOptions(
    custom_predicates={
        "all_match": CustomPredicateDefinition(operator=all_match, argument_type=str),
    },
)

Value Conversion

• Built-in: bool, int, float, Decimal, UUID, date, time, datetime, enum
• Custom converters: ValueConverterRegistry + with_converter
• Field-scoped: field_value_converters={"created_at": my_converter}
• Model-scoped: model_field_value_converters={MyModel: {"field": my_converter}}

Join Hints

from pyrsql import QueryOptions
from pyrsql.core.joins import JoinHint

options = QueryOptions(join_hints={"User.company": JoinHint.LEFT})

PostgreSQL JSON / JSONB

• Whole-document: direct ==, !=, =in=, =out=, =na=, =nn= against JSONB columns
• Nested path: jsonb_path_exists via PostgreSQL jsonpath
• Structured values: arrays and objects passed as jsonpath vars
• Temporal: JSONOptions(use_datetime=True) for datetime-aware jsonpath
• JSON sort: text, integer, float, numeric, boolean, date, time, datetime
• Custom function names: JSONOptions(path_exists_function=...)

FastAPI Integration

from fastapi import Depends, FastAPI
from pyrsql.adapters.fastapi import criteria_dependency

app = FastAPI()
dependency = criteria_dependency()

@app.get("/items")
def list_items(criteria = Depends(dependency)):
    ...

• Auto-extracts filter, sort, page, size from query params
• HTTP 422 with structured diagnostics on parse/semantic errors
• OpenAPI examples from configuration
• One-based paging support
• Custom query parameter names

FastAPI + SQLAlchemy Integration

from pyrsql.integrations.fastapi import FastAPISQLAlchemyIntegration

integration = FastAPISQLAlchemyIntegration()

@app.get("/users")
def list_users(stmt = Depends(integration.select_dependency(User))):
    return {"sql": str(stmt)}

• select_dependency, count_select_dependency, paginated_select_dependency
• Declarative resource() with auto-generated OpenAPI examples
• applier_dependency for custom base statements

Documentation

Full documentation at wskr00.github.io/pyrsql.

Section	Description
Quickstart	One-minute primer
Usage	Filter, sort, page, JSON, FastAPI, custom predicates
API Reference	Auto-generated from docstrings
Operators	Complete operator table
Options	QueryOptions, SortOptions, JSONOptions
Architecture	Pipeline, modules, design
Extensibility	Adding backends and adapters
Contributing	Setup, workflow, standards

Development Principles

• Object-oriented design
• SOLID principles
• Google Python Style Guide
• Strong typing
• ORM-neutral public API

License

MIT.