Source code for betty.json.schema

"""
Provide JSON utilities.
"""

from __future__ import annotations

import enum
from json import loads
from pathlib import Path
from typing import Any, Self, cast, final

import aiofiles
from jsonschema.validators import Draft202012Validator
from referencing import Resource, Registry
from typing_extensions import override

from betty.serde.dump import DumpMapping, Dump


[docs] class Schema: """ A JSON Schema. All schemas using this class **MUST** follow JSON Schema Draft 2020-12. To test your own subclasses, use :py:class:`betty.test_utils.json.schema.SchemaTestBase`. """
[docs] def __init__( self, *, def_name: str | None = None, title: str | None = None, description: str | None = None, ): self._def_name = def_name self._schema: DumpMapping[Dump] = { # The entire API assumes this dialect, so enforce it. "$schema": "https://json-schema.org/draft/2020-12/schema", } if title is not None: self.title = title if description is not None: self.description = description
@property def def_name(self) -> str | None: """ The schema machine name when embedded into another schema's ``$defs``. """ return self._def_name @property def schema(self) -> DumpMapping[Dump]: """ The raw JSON Schema. """ return self._schema @property def title(self) -> str | None: """ The schema's human-readable US English (short) title. """ try: return cast(str, self._schema["title"]) except KeyError: return None @title.setter def title(self, title: str) -> None: self._schema["title"] = title @property def description(self) -> str | None: """ The schema's human-readable US English (long) description. """ try: return cast(str, self._schema["description"]) except KeyError: return None @description.setter def description(self, description: str) -> None: self._schema["description"] = description @property def defs(self) -> DumpMapping[Dump]: """ The JSON Schema's ``$defs`` definitions, kept separately, so they can be merged when this schema is embedded. Only top-level definitions are supported. You **MUST NOT** nest definitions. Instead, prefix or suffix their names. """ return cast(DumpMapping[Dump], self._schema.setdefault("$defs", {}))
[docs] def embed(self, into: Schema) -> DumpMapping[Dump]: """ Embed this schema. This is where the raw schema may be enhanced before being returned. """ for name, schema in self.defs.items(): into.defs[name] = schema schema = { child_name: child_schema for child_name, child_schema in self.schema.items() if child_name not in ("$defs", "$schema") } if self._def_name is None: return schema into.defs[self._def_name] = schema return Ref(self._def_name).embed(into)
[docs] def validate(self, data: Any) -> None: """ Validate data against this schema. """ schema = self.schema if "$id" not in schema: schema["$id"] = "https://betty.example.com" schema_registry = Resource.from_contents(schema) @ Registry() validator = Draft202012Validator( schema, registry=schema_registry, ) validator.validate(data)
class _Type(Schema): _type: str def __init__( self, *, def_name: str | None = None, title: str | None = None, description: str | None = None, ): super().__init__(def_name=def_name, title=title, description=description) self._schema["type"] = self._type
[docs] class String(_Type): """ A JSON Schema ``string`` type. """ _type = "string"
[docs] class Format(enum.Enum): """ A JSON Schema ``string`` type's ``format``. """ DATE_TIME = "date-time" TIME = "time" DATE = "date" DURATION = "duration" EMAIL = "email" IDN_EMAIL = "idn-email" HOSTNAME = "hostname" IDN_HOSTNAME = "idn-hostname" IPV4 = "ipv4" IPV6 = "ipv6" UUID = "uuid" URI = "uri" URI_REFERENCE = "uri-reference" IRI = "iri" IRI_REFERENCE = "iri-reference" URI_TEMPLATE = "uri-template" JSON_POINTER = "json-pointer" RELATIVE_JSON_POINTER = "relative-json-pointer" REGEX = "regex"
[docs] def __init__( self, *, def_name: str | None = None, title: str | None = None, description: str | None = None, min_length: int | None = None, max_length: int | None = None, pattern: str | None = None, format: Format | None = None, # noqa A002 ): super().__init__( def_name=def_name, title=title, description=description, ) if min_length is not None: self._schema["minLength"] = min_length if max_length is not None: self._schema["maxLength"] = max_length if pattern is not None: self._schema["pattern"] = pattern if format is not None: self._schema["format"] = format.value
[docs] class Boolean(_Type): """ A JSON Schema ``boolean`` type. """ _type = "boolean"
[docs] class Number(_Type): """ A JSON Schema ``number`` type. """ _type = "number"
[docs] class Integer(_Type): """ A JSON Schema ``integer`` type. """ _type = "integer"
[docs] class Null(_Type): """ A JSON Schema ``null`` type. """ _type = "null"
[docs] class Object(_Type): """ A JSON Schema ``object`` type. """ _type = "object"
[docs] def __init__( self, *, def_name: str | None = None, title: str | None = None, description: str | None = None, ): super().__init__( def_name=def_name, title=title, description=description, ) self._properties = self._schema["properties"] = {} self._required = self._schema["required"] = []
[docs] def add_property( self, property_name: str, property_schema: Schema, property_required: bool = True, ) -> None: """ Add a property to the object schema. """ self._properties[property_name] = property_schema.embed(self) if property_required: self._required.append(property_name)
[docs] class Array(_Type): """ A JSON Schema ``array`` type. """ _type = "array"
[docs] def __init__( self, items: Schema, *, def_name: str | None = None, title: str | None = None, description: str | None = None, ): super().__init__( def_name=def_name, title=title, description=description, ) self._schema["items"] = items.embed(self)
class _Container(Schema): _type: str def __init__( self, *items: Schema, def_name: str | None = None, title: str | None = None, description: str | None = None, ): super().__init__(def_name=def_name, title=title, description=description) self._schema[self._type] = [item.embed(self) for item in items]
[docs] class AllOf(_Container): """ A JSON Schema ``allOf``. """ _type = "allOf"
[docs] class AnyOf(_Container): """ A JSON Schema ``anyOf``. """ _type = "anyOf"
[docs] class OneOf(_Container): """ A JSON Schema ``oneOf``. """ _type = "oneOf"
[docs] class Const(Schema): """ A JSON Schema ``const``. """
[docs] def __init__( self, const: Dump, *, def_name: str | None = None, title: str | None = None, description: str | None = None, ): super().__init__(def_name=def_name, title=title, description=description) self._schema["const"] = const
[docs] class Enum(Schema): """ A JSON Schema ``enum``. """
[docs] def __init__( self, *values: Dump, def_name: str | None = None, title: str | None = None, description: str | None = None, ): super().__init__(def_name=def_name, title=title, description=description) self._schema["enum"] = list(values)
[docs] class Def(str): """ The name of a named Betty schema. Using this instead of :py:class:`str` directly allows Betty to bundle schemas together under a project namespace. See :py:attr:`betty.json.schema.Schema.def_name`. """ __slots__ = ()
[docs] @override def __new__(cls, def_name: str): return super().__new__(cls, f"#/$defs/{def_name}")
[docs] class Ref(Schema): """ A JSON Schema that references a named Betty schema. """
[docs] def __init__(self, def_name: str): super().__init__() self._schema["$ref"] = Def(def_name)
[docs] class JsonSchemaReference(String): """ The JSON Schema schema. """
[docs] def __init__(self): super().__init__( def_name="jsonSchemaReference", title="JSON Schema reference", format=String.Format.URI, description="A JSON Schema URI.", )
[docs] class FileBasedSchema(Schema): """ A JSON Schema that is stored in a file. """
[docs] @classmethod async def new_for( cls, file_path: Path, *, def_name: str | None = None, title: str | None = None, description: str | None = None, ) -> Self: """ Create a new instance. """ async with aiofiles.open(file_path) as f: raw_schema = await f.read() schema = cls(def_name=def_name, title=title, description=description) schema._schema = loads(raw_schema) # type: ignore[assignment] return schema
[docs] @final class JsonSchemaSchema(FileBasedSchema): """ The JSON Schema Draft 2020-12 schema. """
[docs] @classmethod async def new(cls) -> Self: """ Create a new instance. """ return await cls.new_for( Path(__file__).parent / "schemas" / "json-schema.json", def_name="jsonSchema", title="JSON Schema", )