Source code for apispec.ext.marshmallow.field_converter

"""Utilities for generating OpenAPI Specification (fka Swagger) entities from
:class:`Fields <marshmallow.fields.Field>`.

.. warning::

    This module is treated as private API.
    Users should not need to use this module directly.
"""

from __future__ import annotations

import functools
import operator
import re
import typing
import warnings

import marshmallow
from marshmallow.orderedset import OrderedSet
from packaging.version import Version

# marshmallow field => (JSON Schema type, format)
DEFAULT_FIELD_MAPPING: dict[type, tuple[str | None, str | None]] = {
    marshmallow.fields.Integer: ("integer", None),
    marshmallow.fields.Number: ("number", None),
    marshmallow.fields.Float: ("number", None),
    marshmallow.fields.Decimal: ("number", None),
    marshmallow.fields.String: ("string", None),
    marshmallow.fields.Boolean: ("boolean", None),
    marshmallow.fields.UUID: ("string", "uuid"),
    marshmallow.fields.DateTime: ("string", "date-time"),
    marshmallow.fields.Date: ("string", "date"),
    marshmallow.fields.Time: ("string", None),
    marshmallow.fields.TimeDelta: ("integer", None),
    marshmallow.fields.Email: ("string", "email"),
    marshmallow.fields.URL: ("string", "url"),
    marshmallow.fields.Dict: ("object", None),
    marshmallow.fields.Field: (None, None),
    marshmallow.fields.Raw: (None, None),
    marshmallow.fields.List: ("array", None),
    marshmallow.fields.IP: ("string", "ip"),
    marshmallow.fields.IPv4: ("string", "ipv4"),
    marshmallow.fields.IPv6: ("string", "ipv6"),
}


# Properties that may be defined in a field's metadata that will be added to the output
# of field2property
# https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#schemaObject
_VALID_PROPERTIES = {
    "format",
    "title",
    "description",
    "default",
    "multipleOf",
    "maximum",
    "exclusiveMaximum",
    "minimum",
    "exclusiveMinimum",
    "maxLength",
    "minLength",
    "pattern",
    "maxItems",
    "minItems",
    "uniqueItems",
    "maxProperties",
    "minProperties",
    "required",
    "enum",
    "type",
    "items",
    "allOf",
    "oneOf",
    "anyOf",
    "not",
    "properties",
    "additionalProperties",
    "readOnly",
    "writeOnly",
    "xml",
    "externalDocs",
    "example",
    "nullable",
    "deprecated",
}


_VALID_PREFIX = "x-"


[docs] class FieldConverterMixin: """Adds methods for converting marshmallow fields to an OpenAPI properties.""" field_mapping: dict[type, tuple[str | None, str | None]] = DEFAULT_FIELD_MAPPING openapi_version: Version def init_attribute_functions(self): self.attribute_functions = [ # self.field2type_and_format should run first # as other functions may rely on its output self.field2type_and_format, self.field2default, self.field2choices, self.field2read_only, self.field2write_only, self.field2nullable, self.field2range, self.field2length, self.field2pattern, self.metadata2properties, self.enum2properties, self.nested2properties, self.pluck2properties, self.list2properties, self.dict2properties, self.timedelta2properties, self.datetime2properties, ]
[docs] def map_to_openapi_type(self, field_cls, *args): """Set mapping for custom field class. :param type field_cls: Field class to set mapping for. ``*args`` can be: - a pair of the form ``(type, format)`` - a core marshmallow field type (in which case we reuse that type's mapping) """ if len(args) == 1 and args[0] in self.field_mapping: openapi_type_field = self.field_mapping[args[0]] elif len(args) == 2: openapi_type_field = args else: raise TypeError("Pass core marshmallow field type or (type, fmt) pair.") self.field_mapping[field_cls] = openapi_type_field
[docs] def add_attribute_function(self, func): """Method to add an attribute function to the list of attribute functions that will be called on a field to convert it from a field to an OpenAPI property. :param func func: the attribute function to add The attribute function will be bound to the `OpenAPIConverter <apispec.ext.marshmallow.openapi.OpenAPIConverter>` instance. It will be called for each field in a schema with `self <apispec.ext.marshmallow.openapi.OpenAPIConverter>` and a `field <marshmallow.fields.Field>` instance positional arguments and `ret <dict>` keyword argument. Must return a dictionary of OpenAPI properties that will be shallow merged with the return values of all other attribute functions called on the field. User added attribute functions will be called after all built-in attribute functions in the order they were added. The merged results of all previously called attribute functions are accessible via the `ret` argument. """ bound_func = func.__get__(self) setattr(self, func.__name__, bound_func) self.attribute_functions.append(bound_func)
[docs] def field2property(self, field: marshmallow.fields.Field) -> dict: """Return the JSON Schema property definition given a marshmallow :class:`Field <marshmallow.fields.Field>`. Will include field metadata that are valid properties of OpenAPI schema objects (e.g. "description", "enum", "example"). https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#schemaObject :param Field field: A marshmallow field. :rtype: dict, a Property Object """ ret: dict = {} for attr_func in self.attribute_functions: ret.update(attr_func(field, ret=ret)) return ret
[docs] def field2type_and_format( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return the dictionary of OpenAPI type and format based on the field type. :param Field field: A marshmallow field. :rtype: dict """ # If this type isn't directly in the field mapping then check the # hierarchy until we find something that does. for field_class in type(field).__mro__: if field_class in self.field_mapping: type_, fmt = self.field_mapping[field_class] break else: warnings.warn( f"Field of type {type(field)} does not inherit from marshmallow.Field.", UserWarning, stacklevel=2, ) type_, fmt = "string", None ret = {} if type_: ret["type"] = type_ if fmt: ret["format"] = fmt return ret
[docs] def field2default( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return the dictionary containing the field's default value. Will first look for a `default` key in the field's metadata and then fall back on the field's `missing` parameter. A callable passed to the field's missing parameter will be ignored. :param Field field: A marshmallow field. :rtype: dict """ ret = {} if "default" in field.metadata: ret["default"] = field.metadata["default"] else: default = field.load_default if default is not marshmallow.missing and not callable(default): default = field._serialize(default, None, None) ret["default"] = default return ret
[docs] def field2choices( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return the dictionary of OpenAPI field attributes for valid choices definition. :param Field field: A marshmallow field. :rtype: dict """ attributes = {} comparable = [ validator.comparable for validator in field.validators if hasattr(validator, "comparable") ] if comparable: attributes["enum"] = comparable else: choices = [ OrderedSet(validator.choices) for validator in field.validators if hasattr(validator, "choices") ] if choices: attributes["enum"] = list(functools.reduce(operator.and_, choices)) if field.allow_none: enum = attributes.get("enum") if enum is not None and None not in enum: attributes["enum"].append(None) return attributes
[docs] def field2read_only( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return the dictionary of OpenAPI field attributes for a dump_only field. :param Field field: A marshmallow field. :rtype: dict """ attributes = {} if field.dump_only: attributes["readOnly"] = True return attributes
[docs] def field2write_only( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return the dictionary of OpenAPI field attributes for a load_only field. :param Field field: A marshmallow field. :rtype: dict """ attributes = {} if field.load_only and self.openapi_version.major >= 3: attributes["writeOnly"] = True return attributes
[docs] def field2nullable(self, field: marshmallow.fields.Field, ret) -> dict: """Return the dictionary of OpenAPI field attributes for a nullable field. :param Field field: A marshmallow field. :rtype: dict """ attributes: dict = {} if field.allow_none: if self.openapi_version.major < 3: attributes["x-nullable"] = True elif self.openapi_version.minor < 1: attributes["nullable"] = True else: attributes["type"] = [*make_type_list(ret.get("type")), "null"] return attributes
[docs] def field2range(self, field: marshmallow.fields.Field, ret) -> dict: """Return the dictionary of OpenAPI field attributes for a set of :class:`Range <marshmallow.validators.Range>` validators. :param Field field: A marshmallow field. :rtype: dict """ validators = [ validator for validator in field.validators if ( hasattr(validator, "min") and hasattr(validator, "max") and not hasattr(validator, "equal") ) ] min_attr, max_attr = ( ("minimum", "maximum") if set(make_type_list(ret.get("type"))) & {"number", "integer"} else ("x-minimum", "x-maximum") ) # Serialize min/max values with the field to which the validator is applied return { k: field._serialize(v, None, None) for k, v in make_min_max_attributes(validators, min_attr, max_attr).items() }
[docs] def field2length( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return the dictionary of OpenAPI field attributes for a set of :class:`Length <marshmallow.validators.Length>` validators. :param Field field: A marshmallow field. :rtype: dict """ validators = [ validator for validator in field.validators if ( hasattr(validator, "min") and hasattr(validator, "max") and hasattr(validator, "equal") ) ] is_array = isinstance( field, (marshmallow.fields.Nested, marshmallow.fields.List) ) min_attr = "minItems" if is_array else "minLength" max_attr = "maxItems" if is_array else "maxLength" equal_list = [ validator.equal for validator in validators if validator.equal is not None ] if equal_list: return {min_attr: equal_list[0], max_attr: equal_list[0]} return make_min_max_attributes(validators, min_attr, max_attr)
[docs] def field2pattern( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return the dictionary of OpenAPI field attributes for a :class:`Regexp <marshmallow.validators.Regexp>` validator. If there is more than one such validator, only the first is used in the output spec. :param Field field: A marshmallow field. :rtype: dict """ regex_validators = ( v for v in field.validators if isinstance(getattr(v, "regex", None), re.Pattern) ) v = next(regex_validators, None) attributes = {} if v is None else {"pattern": v.regex.pattern} # type:ignore if next(regex_validators, None) is not None: warnings.warn( f"More than one regex validator defined on {type(field)} field. Only the " "first one will be used in the output spec.", UserWarning, stacklevel=2, ) return attributes
[docs] def metadata2properties( self, field: marshmallow.fields.Field, **kwargs: typing.Any ) -> dict: """Return a dictionary of properties extracted from field metadata. Will include field metadata that are valid properties of `OpenAPI schema objects <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#schemaObject>`_ (e.g. "description", "enum", "example"). In addition, `specification extensions <https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#specification-extensions>`_ are supported. Prefix `x_` to the desired extension when passing the keyword argument to the field constructor. apispec will convert `x_` to `x-` to comply with OpenAPI. :param Field field: A marshmallow field. :rtype: dict """ # Dasherize metadata that starts with x_ metadata = { key.replace("_", "-") if key.startswith("x_") else key: value for key, value in field.metadata.items() if isinstance(key, str) } # Avoid validation error with "Additional properties not allowed" ret = { key: value for key, value in metadata.items() if key in _VALID_PROPERTIES or key.startswith(_VALID_PREFIX) } return ret
[docs] def nested2properties(self, field: marshmallow.fields.Field, ret) -> dict: """Return a dictionary of properties from :class:`Nested <marshmallow.fields.Nested` fields. Typically provides a reference object and will add the schema to the spec if it is not already present If a custom `schema_name_resolver` function returns `None` for the nested schema a JSON schema object will be returned :param Field field: A marshmallow field. :rtype: dict """ # Pluck is a subclass of Nested but is in essence a single field; it # is treated separately by pluck2properties. if isinstance(field, marshmallow.fields.Nested) and not isinstance( field, marshmallow.fields.Pluck ): schema_dict = self.resolve_nested_schema(field.schema) # type:ignore if ret and "$ref" in schema_dict: ret.update({"allOf": [schema_dict]}) else: ret.update(schema_dict) return ret
[docs] def pluck2properties(self, field, **kwargs: typing.Any) -> dict: """Return a dictionary of properties from :class:`Pluck <marshmallow.fields.Pluck` fields. Pluck effectively trans-includes a field from another schema into this, possibly wrapped in an array (`many=True`). :param Field field: A marshmallow field. :rtype: dict """ if isinstance(field, marshmallow.fields.Pluck): plucked_field = field.schema.fields[field.field_name] ret = self.field2property(plucked_field) return {"type": "array", "items": ret} if field.many else ret return {}
[docs] def list2properties(self, field, **kwargs: typing.Any) -> dict: """Return a dictionary of properties from :class:`List <marshmallow.fields.List>` fields. Will provide an `items` property based on the field's `inner` attribute :param Field field: A marshmallow field. :rtype: dict """ ret = {} if isinstance(field, marshmallow.fields.List): ret["items"] = self.field2property(field.inner) return ret
[docs] def dict2properties(self, field, **kwargs: typing.Any) -> dict: """Return a dictionary of properties from :class:`Dict <marshmallow.fields.Dict>` fields. Only applicable for Marshmallow versions greater than 3. Will provide an `additionalProperties` property based on the field's `value_field` attribute :param Field field: A marshmallow field. :rtype: dict """ ret = {} if isinstance(field, marshmallow.fields.Dict): value_field = field.value_field if value_field: ret["additionalProperties"] = self.field2property(value_field) return ret
[docs] def timedelta2properties(self, field, **kwargs: typing.Any) -> dict: """Return a dictionary of properties from :class:`TimeDelta <marshmallow.fields.TimeDelta>` fields. Adds a `x-unit` vendor property based on the field's `precision` attribute :param Field field: A marshmallow field. :rtype: dict """ ret = {} if isinstance(field, marshmallow.fields.TimeDelta): ret["x-unit"] = field.precision return ret
[docs] def enum2properties(self, field, **kwargs: typing.Any) -> dict: """Return a dictionary of properties from :class:`Enum <marshmallow.fields.Enum` fields. :param Field field: A marshmallow field. :rtype: dict """ ret = {} if isinstance(field, marshmallow.fields.Enum): ret = self.field2property(field.field) if field.by_value is False: choices = (m for m in field.enum.__members__) else: choices = (m.value for m in field.enum) ret["enum"] = [field.field._serialize(v, None, None) for v in choices] if field.allow_none and None not in ret["enum"]: ret["enum"].append(None) return ret
[docs] def datetime2properties(self, field, **kwargs: typing.Any) -> dict: """Return a dictionary of properties from :class:`DateTime <marshmallow.fields.DateTime` fields. :param Field field: A marshmallow field. :rtype: dict """ ret = {} if isinstance(field, marshmallow.fields.DateTime) and not isinstance( field, marshmallow.fields.Date ): if field.format == "iso" or field.format is None: # Will return { "type": "string", "format": "date-time" } # as specified inside DEFAULT_FIELD_MAPPING pass elif field.format == "rfc": ret = { "type": "string", "format": None, "example": "Wed, 02 Oct 2002 13:00:00 GMT", "pattern": r"((Mon|Tue|Wed|Thu|Fri|Sat|Sun), ){0,1}\d{2} " + r"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) \d{4} \d{2}:\d{2}:\d{2} " + r"(UT|GMT|EST|EDT|CST|CDT|MST|MDT|PST|PDT|(Z|A|M|N)|(\+|-)\d{4})", } elif field.format == "timestamp": ret = { "type": "number", "format": "float", "example": "1676451245.596", "min": "0", } elif field.format == "timestamp_ms": ret = { "type": "number", "format": "float", "example": "1676451277514.654", "min": "0", } else: ret = { "type": "string", "format": None, "pattern": field.metadata["pattern"] if field.metadata.get("pattern") else None, } return ret
[docs] def make_type_list(types): """Return a list of types from a type attribute Since OpenAPI 3.1.0, "type" can be a single type as string or a list of types, including 'null'. This function takes a "type" attribute as input and returns it as a list, be it an empty or single-element list. This is useful to factorize type-conditional code or code adding a type. """ if types is None: return [] if isinstance(types, str): return [types] return types
[docs] def make_min_max_attributes(validators, min_attr, max_attr) -> dict: """Return a dictionary of minimum and maximum attributes based on a list of validators. If either minimum or maximum values are not present in any of the validator objects that attribute will be omitted. :param validators list: A list of `Marshmallow` validator objects. Each objct is inspected for a minimum and maximum values :param min_attr string: The OpenAPI attribute for the minimum value :param max_attr string: The OpenAPI attribute for the maximum value """ attributes = {} min_list = [validator.min for validator in validators if validator.min is not None] max_list = [validator.max for validator in validators if validator.max is not None] if min_list: attributes[min_attr] = max(min_list) if max_list: attributes[max_attr] = min(max_list) return attributes