jsonschema

Convert JSON Schema to Python types with validation.

marvin.utilities.jsonschema

Convert JSON Schema to Python types with validation.

The jsonschema_to_type function converts a JSON Schema into a Python type that can be used for validation with Pydantic. It supports:

• Basic types (string, number, integer, boolean, null)
• Complex types (arrays, objects)
• Format constraints (date-time, email, uri)
• Numeric constraints (minimum, maximum, multipleOf)
• String constraints (minLength, maxLength, pattern)
• Array constraints (minItems, maxItems, uniqueItems)
• Object properties with defaults
• References and recursive schemas
• Enums and constants
• Union types

Example:

schema = {
    "type": "object",
    "properties": {
        "name": {"type": "string", "minLength": 1},
        "age": {"type": "integer", "minimum": 0},
        "email": {"type": "string", "format": "email"}
    },
    "required": ["name", "age"]
}

# Name is optional and will be inferred from schema's "title" property if not provided
Person = jsonschema_to_type(schema)
# Creates a validated dataclass with name, age, and optional email fields

Constants

FORMAT_TYPES

FORMAT_TYPES = {'date-time': datetime, 'email': EmailStr, 'uri': AnyUrl, 'json': Json}

Classes

JSONSchema

class JSONSchema()

Functions

create_array_type

def create_array_type(schema: Mapping[str, Any], schemas: Mapping[str, Any]) -> type | Annotated[Any, ...]

Create list/set type with optional constraints.

create_dataclass

def create_dataclass(schema: Mapping[str, Any], name: str | None = None, schemas: Mapping[str, Any] | None = None) -> type

Create dataclass from object schema.

create_enum

def create_enum(name: str, values: list[Any]) -> type | Enum

Create enum type from list of values.

create_field_with_default

def create_field_with_default(field_type: type, default_value: Any, schema: dict[str, Any]) -> Any

Create a field with simplified default handling.

create_numeric_type

def create_numeric_type(base: Type[Union[int, float]], schema: Mapping[str, Any]) -> type | Annotated[Any, ...]

Create numeric type with optional constraints.

create_string_type

def create_string_type(schema: Mapping[str, Any]) -> type | Annotated[Any, ...]

Create string type with optional constraints.

get_default_value

def get_default_value(schema: dict[str, Any], prop_name: str, parent_default: dict[str, Any] | None = None) -> Any

Get default value with proper priority ordering.

1. Value from parent’s default if it exists
2. Property’s own default if it exists
3. None

hash_schema

def hash_schema(schema: Mapping[str, Any]) -> str

Generate a deterministic hash for schema caching.

jsonschema_to_type

def jsonschema_to_type(schema: Mapping[str, Any], name: str | None = None) -> type

Convert JSON schema to appropriate Python type with validation.

Args: schema: A JSON Schema dictionary defining the type structure and validation rules name: Optional name for object schemas. Only allowed when schema type is “object”. If not provided for objects, name will be inferred from schema’s “title” property or default to “Root”.

Returns: A Python type (typically a dataclass for objects) with Pydantic validation

Raises: ValueError: If a name is provided for a non-object schema

Examples: Create a dataclass from an object schema:

schema = {
    "type": "object",
    "title": "Person",
    "properties": {
        "name": {"type": "string", "minLength": 1},
        "age": {"type": "integer", "minimum": 0},
        "email": {"type": "string", "format": "email"}
    },
    "required": ["name", "age"]
}

Person = jsonschema_to_type(schema)
# Creates a dataclass with name, age, and optional email fields:
# @dataclass
# class Person:
#     name: str
#     age: int
#     email: str | None = None

Person(name=“John”, age=30)

Create a scalar type with constraints:

schema = {
    "type": "string",
    "minLength": 3,
    "pattern": "^[A-Z][a-z]+$"
}

NameType = jsonschema_to_type(schema)
# Creates Annotated[str, StringConstraints(min_length=3, pattern="^[A-Z][a-z]+$")]

@dataclass
class Name:
    name: NameType

merge_defaults

def merge_defaults(data: Mapping[str, Any], schema: Mapping[str, Any], parent_default: Mapping[str, Any] | None = None) -> dict[str, Any]

Merge defaults with provided data at all levels.

resolve_ref

def resolve_ref(ref: str, schemas: Mapping[str, Any]) -> Mapping[str, Any]

Resolve JSON Schema reference to target schema.

sanitize_name

def sanitize_name(name: str) -> str

Convert string to valid Python identifier.

schema_to_type

def schema_to_type(schema: Mapping[str, Any], schemas: Mapping[str, Any]) -> type

Convert schema to appropriate Python type.

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Parent Module: utilities