import re
import warnings
from decimal import Decimal
from operator import attrgetter
from urllib.parse import urljoin
from django.core.validators import (
DecimalValidator, EmailValidator, MaxLengthValidator, MaxValueValidator,
MinLengthValidator, MinValueValidator, RegexValidator, URLValidator
)
from django.db import models
from django.utils.encoding import force_str
from rest_framework import (
RemovedInDRF315Warning, exceptions, renderers, serializers
)
from rest_framework.compat import uritemplate
from rest_framework.fields import _UnvalidatedField, empty
from rest_framework.settings import api_settings
from .generators import BaseSchemaGenerator
from .inspectors import ViewInspector
from .utils import get_pk_description, is_list_view
class SchemaGenerator(BaseSchemaGenerator):
def get_info(self):
# Title and version are required by openapi specification 3.x
info = {
'title': self.title or '',
'version': self.version or ''
}
if self.description is not None:
info['description'] = self.description
return info
def check_duplicate_operation_id(self, paths):
ids = {}
for route in paths:
for method in paths[route]:
if 'operationId' not in paths[route][method]:
continue
operation_id = paths[route][method]['operationId']
if operation_id in ids:
warnings.warn(
'You have a duplicated operationId in your OpenAPI schema: {operation_id}\n'
'\tRoute: {route1}, Method: {method1}\n'
'\tRoute: {route2}, Method: {method2}\n'
'\tAn operationId has to be unique across your schema. Your schema may not work in other tools.'
.format(
route1=ids[operation_id]['route'],
method1=ids[operation_id]['method'],
route2=route,
method2=method,
operation_id=operation_id
)
)
ids[operation_id] = {
'route': route,
'method': method
}
def get_schema(self, request=None, public=False):
"""
Generate a OpenAPI schema.
"""
self._initialise_endpoints()
components_schemas = {}
# Iterate endpoints generating per method path operations.
paths = {}
_, view_endpoints = self._get_paths_and_endpoints(None if public else request)
for path, method, view in view_endpoints:
if not self.has_view_permissions(path, method, view):
continue
operation = view.schema.get_operation(path, method)
components = view.schema.get_components(path, method)
for k in components.keys():
if k not in components_schemas:
continue
if components_schemas[k] == components[k]:
continue
warnings.warn('Schema component "{}" has been overriden with a different value.'.format(k))
components_schemas.update(components)
# Normalise path for any provided mount url.
if path.startswith('/'):
path = path[1:]
path = urljoin(self.url or '/', path)
paths.setdefault(path, {})
paths[path][method.lower()] = operation
self.check_duplicate_operation_id(paths)
# Compile final schema.
schema = {
'openapi': '3.0.2',
'info': self.get_info(),
'paths': paths,
}
if len(components_schemas) > 0:
schema['components'] = {
'schemas': components_schemas
}
return schema
# View Inspectors
class AutoSchema(ViewInspector):
def __init__(self, tags=None, operation_id_base=None, component_name=None):
"""
:param operation_id_base: user-defined name in operationId. If empty, it will be deducted from the Model/Serializer/View name.
:param component_name: user-defined component's name. If empty, it will be deducted from the Serializer's class name.
"""
if tags and not all(isinstance(tag, str) for tag in tags):
raise ValueError('tags must be a list or tuple of string.')
self._tags = tags
self.operation_id_base = operation_id_base
self.component_name = component_name
super().__init__()
request_media_types = []
response_media_types = []
method_mapping = {
'get': 'retrieve',
'post': 'create',
'put': 'update',
'patch': 'partialUpdate',
'delete': 'destroy',
}
def get_operation(self, path, method):
operation = {}
operation['operationId'] = self.get_operation_id(path, method)
operation['description'] = self.get_description(path, method)
parameters = []
parameters += self.get_path_parameters(path, method)
parameters += self.get_pagination_parameters(path, method)
parameters += self.get_filter_parameters(path, method)
operation['parameters'] = parameters
request_body = self.get_request_body(path, method)
if request_body:
operation['requestBody'] = request_body
operation['responses'] = self.get_responses(path, method)
operation['tags'] = self.get_tags(path, method)
return operation
def get_component_name(self, serializer):
"""
Compute the component's name from the serializer.
Raise an exception if the serializer's class name is "Serializer" (case-insensitive).
"""
if self.component_name is not None:
return self.component_name
# use the serializer's class name as the component name.
component_name = serializer.__class__.__name__
# We remove the "serializer" string from the class name.
pattern = re.compile("serializer", re.IGNORECASE)
component_name = pattern.sub("", component_name)
if component_name == "":
raise Exception(
'"{}" is an invalid class name for schema generation. '
'Serializer\'s class name should be unique and explicit. e.g. "ItemSerializer"'
.format(serializer.__class__.__name__)
)
return component_name
def get_components(self, path, method):
"""
Return components with their properties from the serializer.
"""
if method.lower() == 'delete':
return {}
request_serializer = self.get_request_serializer(path, method)
response_serializer = self.get_response_serializer(path, method)
components = {}
if isinstance(request_serializer, serializers.Serializer):
component_name = self.get_component_name(request_serializer)
content = self.map_serializer(request_serializer)
components.setdefault(component_name, content)
if isinstance(response_serializer, serializers.Serializer):
component_name = self.get_component_name(response_serializer)
content = self.map_serializer(response_serializer)
components.setdefault(component_name, content)
return components
def _to_camel_case(self, snake_str):
components = snake_str.split('_')
# We capitalize the first letter of each component except the first one
# with the 'title' method and join them together.
return components[0] + ''.join(x.title() for x in components[1:])
def get_operation_id_base(self, path, method, action):
"""
Compute the base part for operation ID from the model, serializer or view name.
"""
model = getattr(getattr(self.view, 'queryset', None), 'model', None)
if self.operation_id_base is not None:
name = self.operation_id_base
# Try to deduce the ID from the view's model
elif model is not None:
name = model.__name__
# Try with the serializer class name
elif self.get_serializer(path, method) is not None:
name = self.get_serializer(path, method).__class__.__name__
if name.endswith('Serializer'):
name = name[:-10]
# Fallback to the view name
else:
name = self.view.__class__.__name__
if name.endswith('APIView'):
name = name[:-7]
elif name.endswith('View'):
name = name[:-4]
# Due to camel-casing of classes and `action` being lowercase, apply title in order to find if action truly
# comes at the end of the name
if name.endswith(action.title()): # ListView, UpdateAPIView, ThingDelete ...
name = name[:-len(action)]
if action == 'list':
from inflection import pluralize
name = pluralize(name)
return name
def get_operation_id(self, path, method):
"""
Compute an operation ID from the view type and get_operation_id_base method.
"""
method_name = getattr(self.view, 'action', method.lower())
if is_list_view(path, method, self.view):
action = 'list'
elif method_name not in self.method_mapping:
action = self._to_camel_case(method_name)
else:
action = self.method_mapping[method.lower()]
name = self.get_operation_id_base(path, method, action)
return action + name
def get_path_parameters(self, path, method):
"""
Return a list of parameters from templated path variables.
"""
assert uritemplate, '`uritemplate` must be installed for OpenAPI schema support.'
model = getattr(getattr(self.view, 'queryset', None), 'model', None)
parameters = []
for variable in uritemplate.variables(path):
description = ''
if model is not None: # TODO: test this.
# Attempt to infer a field description if possible.
try:
model_field = model._meta.get_field(variable)
except Exception:
model_field = None
if model_field is not None and model_field.help_text:
description = force_str(model_field.help_text)
elif model_field is not None and model_field.primary_key:
description = get_pk_description(model, model_field)
parameter = {
"name": variable,
"in": "path",
"required": True,
"description": description,
'schema': {
'type': 'string', # TODO: integer, pattern, ...
},
}
parameters.append(parameter)
return parameters
def get_filter_parameters(self, path, method):
if not self.allows_filters(path, method):
return []
parameters = []
for filter_backend in self.view.filter_backends:
parameters += filter_backend().get_schema_operation_parameters(self.view)
return parameters
def allows_filters(self, path, method):
"""
Determine whether to include filter Fields in schema.
Default implementation looks for ModelViewSet or GenericAPIView
actions/methods that cause filtering on the default implementation.
"""
if getattr(self.view, 'filter_backends', None) is None:
return False
if hasattr(self.view, 'action'):
return self.view.action in ["list", "retrieve", "update", "partial_update", "destroy"]
return method.lower() in ["get", "put", "patch", "delete"]
def get_pagination_parameters(self, path, method):
view = self.view
if not is_list_view(path, method, view):
return []
paginator = self.get_paginator()
if not paginator:
return []
return paginator.get_schema_operation_parameters(view)
def map_choicefield(self, field):
choices = list(dict.fromkeys(field.choices)) # preserve order and remove duplicates
if all(isinstance(choice, bool) for choice in choices):
type = 'boolean'
elif all(isinstance(choice, int) for choice in choices):
type = 'integer'
elif all(isinstance(choice, (int, float, Decimal)) for choice in choices): # `number` includes `integer`
# Ref: https://tools.ietf.org/html/draft-wright-json-schema-validation-00#section-5.21
type = 'number'
elif all(isinstance(choice, str) for choice in choices):
type = 'string'
else:
type = None
mapping = {
# The value of `enum` keyword MUST be an array and SHOULD be unique.
# Ref: https://tools.ietf.org/html/draft-wright-json-schema-validation-00#section-5.20
'enum': choices
}
# If We figured out `type` then and only then we should set it. It must be a string.
# Ref: https://swagger.io/docs/specification/data-models/data-types/#mixed-type
# It is optional but it can not be null.
# Ref: https://tools.ietf.org/html/draft-wright-json-schema-validation-00#section-5.21
if type:
mapping['type'] = type
return mapping
def map_field(self, field):
# Nested Serializers, `many` or not.
if isinstance(field, serializers.ListSerializer):
return {
'type': 'array',
'items': self.map_serializer(field.child)
}
if isinstance(field, serializers.Serializer):
data = self.map_serializer(field)
data['type'] = 'object'
return data
# Related fields.
if isinstance(field, serializers.ManyRelatedField):
return {
'type': 'array',
'items': self.map_field(field.child_relation)
}
if isinstance(field, serializers.PrimaryKeyRelatedField):
if getattr(field, "pk_field", False):
return self.map_field(field=field.pk_field)
model = getattr(field.queryset, 'model', None)
if model is not None:
model_field = model._meta.pk
if isinstance(model_field, models.AutoField):
return {'type': 'integer'}
# ChoiceFields (single and multiple).
# Q:
# - Is 'type' required?
# - can we determine the TYPE of a choicefield?
if isinstance(field, serializers.MultipleChoiceField):
return {
'type': 'array',
'items': self.map_choicefield(field)
}
if isinstance(field, serializers.ChoiceField):
return self.map_choicefield(field)
# ListField.
if isinstance(field, serializers.ListField):
mapping = {
'type': 'array',
'items': {},
}
if not isinstance(field.child, _UnvalidatedField):
mapping['items'] = self.map_field(field.child)
return mapping
# DateField and DateTimeField type is string
if isinstance(field, serializers.DateField):
return {
'type': 'string',
'format': 'date',
}
if isinstance(field, serializers.DateTimeField):
return {
'type': 'string',
'format': 'date-time',
}
# "Formats such as "email", "uuid", and so on, MAY be used even though undefined by this specification."
# see: https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#data-types
# see also: https://swagger.io/docs/specification/data-models/data-types/#string
if isinstance(field, serializers.EmailField):
return {
'type': 'string',
'format': 'email'
}
if isinstance(field, serializers.URLField):
return {
'type': 'string',
'format': 'uri'
}
if isinstance(field, serializers.UUIDField):
return {
'type': 'string',
'format': 'uuid'
}
if isinstance(field, serializers.IPAddressField):
content = {
'type': 'string',
}
if field.protocol != 'both':
content['format'] = field.protocol
return content
if isinstance(field, serializers.DecimalField):
if getattr(field, 'coerce_to_string', api_settings.COERCE_DECIMAL_TO_STRING):
content = {
'type': 'string',
'format': 'decimal',
}
else:
content = {
'type': 'number'
}
if field.decimal_places:
content['multipleOf'] = float('.' + (field.decimal_places - 1) * '0' + '1')
if field.max_whole_digits:
content['maximum'] = int(field.max_whole_digits * '9') + 1
content['minimum'] = -content['maximum']
self._map_min_max(field, content)
return content
if isinstance(field, serializers.FloatField):
content = {
'type': 'number',
}
self._map_min_max(field, content)
return content
if isinstance(field, serializers.IntegerField):
content = {
'type': 'integer'
}
self._map_min_max(field, content)
# 2147483647 is max for int32_size, so we use int64 for format
if int(content.get('maximum', 0)) > 2147483647 or int(content.get('minimum', 0)) > 2147483647:
content['format'] = 'int64'
return content
if isinstance(field, serializers.FileField):
return {
'type': 'string',
'format': 'binary'
}
# Simplest cases, default to 'string' type:
FIELD_CLASS_SCHEMA_TYPE = {
serializers.BooleanField: 'boolean',
serializers.JSONField: 'object',
serializers.DictField: 'object',
serializers.HStoreField: 'object',
}
return {'type': FIELD_CLASS_SCHEMA_TYPE.get(field.__class__, 'string')}
def _map_min_max(self, field, content):
if field.max_value:
content['maximum'] = field.max_value
if field.min_value:
content['minimum'] = field.min_value
def map_serializer(self, serializer):
# Assuming we have a valid serializer instance.
required = []
properties = {}
for field in serializer.fields.values():
if isinstance(field, serializers.HiddenField):
continue
if field.required:
required.append(self.get_field_name(field))
schema = self.map_field(field)
if field.read_only:
schema['readOnly'] = True
if field.write_only:
schema['writeOnly'] = True
if field.allow_null:
schema['nullable'] = True
if field.default is not None and field.default != empty and not callable(field.default):
schema['default'] = field.default
if field.help_text:
schema['description'] = str(field.help_text)
self.map_field_validators(field, schema)
properties[self.get_field_name(field)] = schema
result = {
'type': 'object',
'properties': properties
}
if required:
result['required'] = required
return result
def map_field_validators(self, field, schema):
"""
map field validators
"""
for v in field.validators:
# "Formats such as "email", "uuid", and so on, MAY be used even though undefined by this specification."
# https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#data-types
if isinstance(v, EmailValidator):
schema['format'] = 'email'
if isinstance(v, URLValidator):
schema['format'] = 'uri'
if isinstance(v, RegexValidator):
# In Python, the token \Z does what \z does in other engines.
# https://stackoverflow.com/questions/53283160
schema['pattern'] = v.regex.pattern.replace('\\Z', '\\z')
elif isinstance(v, MaxLengthValidator):
attr_name = 'maxLength'
if isinstance(field, serializers.ListField):
attr_name = 'maxItems'
schema[attr_name] = v.limit_value
elif isinstance(v, MinLengthValidator):
attr_name = 'minLength'
if isinstance(field, serializers.ListField):
attr_name = 'minItems'
schema[attr_name] = v.limit_value
elif isinstance(v, MaxValueValidator):
schema['maximum'] = v.limit_value
elif isinstance(v, MinValueValidator):
schema['minimum'] = v.limit_value
elif isinstance(v, DecimalValidator) and \
not getattr(field, 'coerce_to_string', api_settings.COERCE_DECIMAL_TO_STRING):
if v.decimal_places:
schema['multipleOf'] = float('.' + (v.decimal_places - 1) * '0' + '1')
if v.max_digits:
digits = v.max_digits
if v.decimal_places is not None and v.decimal_places > 0:
digits -= v.decimal_places
schema['maximum'] = int(digits * '9') + 1
schema['minimum'] = -schema['maximum']
def get_field_name(self, field):
"""
Override this method if you want to change schema field name.
For example, convert snake_case field name to camelCase.
"""
return field.field_name
def get_paginator(self):
pagination_class = getattr(self.view, 'pagination_class', None)
if pagination_class:
return pagination_class()
return None
def map_parsers(self, path, method):
return list(map(attrgetter('media_type'), self.view.parser_classes))
def map_renderers(self, path, method):
media_types = []
for renderer in self.view.renderer_classes:
# BrowsableAPIRenderer not relevant to OpenAPI spec
if issubclass(renderer, renderers.BrowsableAPIRenderer):
continue
media_types.append(renderer.media_type)
return media_types
def get_serializer(self, path, method):
view = self.view
if not hasattr(view, 'get_serializer'):
return None
try:
return view.get_serializer()
except exceptions.APIException:
warnings.warn('{}.get_serializer() raised an exception during '
'schema generation. Serializer fields will not be '
'generated for {} {}.'
.format(view.__class__.__name__, method, path))
return None
def get_request_serializer(self, path, method):
"""
Override this method if your view uses a different serializer for
handling request body.
"""
return self.get_serializer(path, method)
def get_response_serializer(self, path, method):
"""
Override this method if your view uses a different serializer for
populating response data.
"""
return self.get_serializer(path, method)
def get_reference(self, serializer):
return {'$ref': '#/components/schemas/{}'.format(self.get_component_name(serializer))}
def get_request_body(self, path, method):
if method not in ('PUT', 'PATCH', 'POST'):
return {}
self.request_media_types = self.map_parsers(path, method)
serializer = self.get_request_serializer(path, method)
if not isinstance(serializer, serializers.Serializer):
item_schema = {}
else:
item_schema = self.get_reference(serializer)
return {
'content': {
ct: {'schema': item_schema}
for ct in self.request_media_types
}
}
def get_responses(self, path, method):
if method == 'DELETE':
return {
'204': {
'description': ''
}
}
self.response_media_types = self.map_renderers(path, method)
serializer = self.get_response_serializer(path, method)
if not isinstance(serializer, serializers.Serializer):
item_schema = {}
else:
item_schema = self.get_reference(serializer)
if is_list_view(path, method, self.view):
response_schema = {
'type': 'array',
'items': item_schema,
}
paginator = self.get_paginator()
if paginator:
response_schema = paginator.get_paginated_response_schema(response_schema)
else:
response_schema = item_schema
status_code = '201' if method == 'POST' else '200'
return {
status_code: {
'content': {
ct: {'schema': response_schema}
for ct in self.response_media_types
},
# description is a mandatory property,
# https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#responseObject
# TODO: put something meaningful into it
'description': ""
}
}
def get_tags(self, path, method):
# If user have specified tags, use them.
if self._tags:
return self._tags
# First element of a specific path could be valid tag. This is a fallback solution.
# PUT, PATCH, GET(Retrieve), DELETE: /user_profile/{id}/ tags = [user-profile]
# POST, GET(List): /user_profile/ tags = [user-profile]
if path.startswith('/'):
path = path[1:]
return [path.split('/')[0].replace('_', '-')]
def _get_reference(self, serializer):
warnings.warn(
"Method `_get_reference()` has been renamed to `get_reference()`. "
"The old name will be removed in DRF v3.15.",
RemovedInDRF315Warning, stacklevel=2
)
return self.get_reference(serializer)