"""Utilities for generating OpenAPI Specification (fka Swagger) entities from
marshmallow :class:`Schemas <marshmallow.Schema>` and :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 typing
import marshmallow
import marshmallow.exceptions
from marshmallow.utils import is_collection
from packaging.version import Version
from apispec import APISpec
from apispec.exceptions import APISpecError
from .common import (
get_fields,
get_unique_schema_name,
make_schema_key,
resolve_schema_instance,
)
from .field_converter import FieldConverterMixin
__location_map__ = {
"match_info": "path",
"query": "query",
"querystring": "query",
"json": "body",
"headers": "header",
"cookies": "cookie",
"form": "formData",
"files": "formData",
}
[docs]
class OpenAPIConverter(FieldConverterMixin):
"""Adds methods for generating OpenAPI specification from marshmallow schemas and fields.
:param Version|str openapi_version: The OpenAPI version to use.
Should be in the form '2.x' or '3.x.x' to comply with the OpenAPI standard.
:param callable schema_name_resolver: Callable to generate the schema definition name.
Receives the `Schema` class and returns the name to be used in refs within
the generated spec. When working with circular referencing this function
must must not return `None` for schemas in a circular reference chain.
:param APISpec spec: An initalied spec. Nested schemas will be added to the
spec
"""
def __init__(
self,
openapi_version: Version | str,
schema_name_resolver,
spec: APISpec,
) -> None:
self.openapi_version = (
Version(openapi_version)
if isinstance(openapi_version, str)
else openapi_version
)
self.schema_name_resolver = schema_name_resolver
self.spec = spec
self.init_attribute_functions()
self.init_parameter_attribute_functions()
# Schema references
self.refs: dict = {}
def init_parameter_attribute_functions(self) -> None:
self.parameter_attribute_functions = [
self.field2required,
self.list2param,
]
[docs]
def add_parameter_attribute_function(self, func) -> None:
"""Method to add a field parameter function to the list of field
parameter functions that will be called on a field to convert it to a
field parameter.
:param func func: the field parameter 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.
May mutate `ret`.
User added field parameter functions will be called after all built-in
field parameter functions in the order they were added.
"""
bound_func = func.__get__(self)
setattr(self, func.__name__, bound_func)
self.parameter_attribute_functions.append(bound_func)
[docs]
def resolve_nested_schema(self, schema):
"""Return the OpenAPI representation of a marshmallow Schema.
Adds the schema to the spec if it isn't already present.
Typically will return a dictionary with the reference to the schema's
path in the spec unless the `schema_name_resolver` returns `None`, in
which case the returned dictionary will contain a JSON Schema Object
representation of the schema.
:param schema: schema to add to the spec
"""
try:
schema_instance = resolve_schema_instance(schema)
# If schema is a string and is not found in registry,
# assume it is a schema reference
except marshmallow.exceptions.RegistryError:
return schema
schema_key = make_schema_key(schema_instance)
if schema_key not in self.refs:
name = self.schema_name_resolver(schema)
if not name:
try:
json_schema = self.schema2jsonschema(schema_instance)
except RuntimeError as exc:
raise APISpecError(
f"Name resolver returned None for schema {schema} which is "
"part of a chain of circular referencing schemas. Please"
" ensure that the schema_name_resolver passed to"
" MarshmallowPlugin returns a string for all circular"
" referencing schemas."
) from exc
if getattr(schema, "many", False):
return {"type": "array", "items": json_schema}
return json_schema
name = get_unique_schema_name(self.spec.components, name)
self.spec.components.schema(name, schema=schema)
return self.get_ref_dict(schema_instance)
[docs]
def schema2parameters(
self,
schema,
*,
location,
name: str = "body",
required: bool = False,
description: str | None = None,
):
"""Return an array of OpenAPI parameters given a given marshmallow
:class:`Schema <marshmallow.Schema>`. If `location` is "body", then return an array
of a single parameter; else return an array of a parameter for each included field in
the :class:`Schema <marshmallow.Schema>`.
In OpenAPI 3, only "query", "header", "path" or "cookie" are allowed for the location
of parameters. "requestBody" is used when fields are in the body.
https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#parameterObject
"""
location = __location_map__.get(location, location)
# OAS 2 body parameter
if location == "body":
param = {
"in": location,
"required": required,
"name": name,
"schema": self.resolve_nested_schema(schema),
}
if description:
param["description"] = description
return [param]
assert not getattr(
schema, "many", False
), "Schemas with many=True are only supported for 'json' location (aka 'in: body')"
fields = get_fields(schema, exclude_dump_only=True)
return [
self._field2parameter(
field_obj,
name=field_obj.data_key or field_name,
location=location,
)
for field_name, field_obj in fields.items()
]
def _field2parameter(
self, field: marshmallow.fields.Field, *, name: str, location: str
) -> dict:
"""Return an OpenAPI parameter as a `dict`, given a marshmallow
:class:`Field <marshmallow.Field>`.
https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#parameterObject
"""
ret: dict = {"in": location, "name": name}
prop = self.field2property(field)
if self.openapi_version.major < 3:
ret.update(prop)
else:
if "description" in prop:
ret["description"] = prop.pop("description")
if "deprecated" in prop:
ret["deprecated"] = prop.pop("deprecated")
ret["schema"] = prop
for param_attr_func in self.parameter_attribute_functions:
ret.update(param_attr_func(field, ret=ret))
return ret
[docs]
def field2required(
self, field: marshmallow.fields.Field, **kwargs: typing.Any
) -> dict:
"""Return the dictionary of OpenAPI parameter attributes for a required field.
:param Field field: A marshmallow field.
:rtype: dict
"""
ret = {}
partial = getattr(field.parent, "partial", False)
ret["required"] = field.required and (
not partial or (is_collection(partial) and field.name not in partial) # type:ignore
)
return ret
[docs]
def list2param(self, field: marshmallow.fields.Field, **kwargs: typing.Any) -> dict:
"""Return a dictionary of parameter properties from
:class:`List <marshmallow.fields.List` fields.
:param Field field: A marshmallow field.
:rtype: dict
"""
ret: dict = {}
if isinstance(field, marshmallow.fields.List):
if self.openapi_version.major < 3:
ret["collectionFormat"] = "multi"
else:
ret["explode"] = True
ret["style"] = "form"
return ret
[docs]
def schema2jsonschema(self, schema):
"""Return the JSON Schema Object for a given marshmallow
:class:`Schema <marshmallow.Schema>` instance. Schema may optionally
provide the ``title`` and ``description`` class Meta options.
https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#schemaObject
:param Schema schema: A marshmallow Schema instance
:rtype: dict, a JSON Schema Object
"""
fields = get_fields(schema)
Meta = getattr(schema, "Meta", None)
partial = getattr(schema, "partial", None)
jsonschema = self.fields2jsonschema(fields, partial=partial)
if hasattr(Meta, "title"):
jsonschema["title"] = Meta.title
if hasattr(Meta, "description"):
jsonschema["description"] = Meta.description
if hasattr(Meta, "unknown") and Meta.unknown != marshmallow.EXCLUDE:
jsonschema["additionalProperties"] = Meta.unknown == marshmallow.INCLUDE
return jsonschema
[docs]
def fields2jsonschema(self, fields, *, partial=None):
"""Return the JSON Schema Object given a mapping between field names and
:class:`Field <marshmallow.Field>` objects.
:param dict fields: A dictionary of field name field object pairs
:param bool|tuple partial: Whether to override a field's required flag.
If `True` no fields will be set as required. If an iterable fields
in the iterable will not be marked as required.
:rtype: dict, a JSON Schema Object
"""
jsonschema = {"type": "object", "properties": {}}
for field_name, field_obj in fields.items():
observed_field_name = field_obj.data_key or field_name
prop = self.field2property(field_obj)
jsonschema["properties"][observed_field_name] = prop
if field_obj.required:
if not partial or (
is_collection(partial) and field_name not in partial
):
jsonschema.setdefault("required", []).append(observed_field_name)
if "required" in jsonschema:
jsonschema["required"].sort()
return jsonschema
[docs]
def get_ref_dict(self, schema):
"""Method to create a dictionary containing a JSON reference to the
schema in the spec
"""
schema_key = make_schema_key(schema)
ref_schema = self.spec.components.get_ref("schema", self.refs[schema_key])
if getattr(schema, "many", False):
return {"type": "array", "items": ref_schema}
return ref_schema