"""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.
"""
import re
import functools
import operator
import typing
import warnings
from packaging.version import Version
import marshmallow
from marshmallow.orderedset import OrderedSet
# marshmallow field => (JSON Schema type, format)
DEFAULT_FIELD_MAPPING = {
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),
}
# 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 = 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,
]
[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 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))
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(
"More than one regex validator defined on {} field. Only the "
"first one will be used in the output spec.".format(type(field)),
UserWarning,
)
return attributes
[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]
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