En este artículo, describiré uno de los enfoques para crear un servicio json api con validación de datos.
El servicio se implementará en aiohttp . Es un marco de Python moderno y en constante evolución que utiliza asyncio
.
Acerca de las anotaciones:
La introducción de anotaciones en el python
código facilitó la comprensión. Además, las anotaciones abren algunas posibilidades adicionales. Son las anotaciones las que juegan un papel clave en la validación de datos para los manejadores de métodos de API en este artículo.
Bibliotecas utilizadas:
- aiohttp : un marco para crear aplicaciones web
- pydantic : clases que le permiten describir datos de forma declarativa y validarlos
- valdec - decorador para validar argumentos y devolver valores de funciones
Tabla de contenido:
- 1. Archivos y carpetas de la aplicación
- 2.json middlewares
- 2.1. Middleware simple para el servicio json
- 2.1.1. Declaración del manejador
- 2.1.2. Clase SimpleHandler para middleware
- 2.1.3. Ejemplos de
- 2.1.3.1. Responder con código 200
- 2.1.3.2. Responder con el código 400
- 2.1.3.3. Responder con código 500
- 2.2. middleware para "controladores kwargs"
- 2.2.1. Declaración del manejador
- 2.2.2. Clase auxiliar ArgumentsManager
- 2.2.3. Clase KwargsHandler para middleware
- 2.2.4.
- 2.2.4.1. /create
- 2.2.4.2. /read
- 2.2.4.3. /info/{info_id}
- 2.3. middleware c /
- 2.3.1. pydantic.BaseModel
- 2.3.2. valdec.validate
- 2.3.3.
- 2.3.4.
- 2.3.5.
- 2.3.6. WrapsKwargsHandler middleware
- 2.3.7.
- 2.3.7.1. /create
- 2.3.7.2. /read
- 2.3.7.3. /info/{info_id}
- 2.3.1. pydantic.BaseModel
- 2.1. Middleware simple para el servicio json
- 3.
- 4.
1.
- sources - - data_classes - - base.py - - person.py - - wraps.py - / - handlers - - kwargs.py - `KwargsHandler.middleware` - simple.py - `SimpleHandler.middleware` - wraps.py - `WrapsKwargsHandler.middleware` - middlewares - middlewares - exceptions.py - - kwargs_handler.py - `KwargsHandler` - simple_handler.py - `SimpleHandler` - utils.py - middlewares - wraps_handler.py - `WrapsKwargsHandler` - requirements.txt - - run_kwargs.py - `KwargsHandler.middleware` - run_simple.py - c `SimpleHandler.middleware` - run_wraps.py - c `WrapsKwargsHandler.middleware` - settings.py - - Dockerfile -
: https://github.com/EvgeniyBurdin/api_service
2. json middlewares
middleware
aiohttp.web.Application()
.
middleware
, , . . middleware
.
middleware
, .
middleware
"" "" web.Request
web.Response
. .
, middleware
/, .
, .
2.1. middleware json
, aiohttp.web.Application()
, , :
from aiohttp import web
async def some_handler(request: web.Request) -> web.Response:
data = await request.json()
...
text = json.dumps(some_data)
...
return web.Response(text=text, ...)
"" web.Request
, json. , . json "" web.Response
( web.json_response()
).
2.1.1.
. , middleware
, , :
from aiohttp import web
async def some_handler(request: web.Request, data: Any) -> Any:
...
return some_data
. web.Request
( ), — python, .
, : data: Any
. ( ), , "" . .
, , :
from aiohttp import web
from typing import Union, List
async def some_handler(
request: web.Request, data: Union[str, List[str]]
) -> List[int]:
...
return some_data
2.1.2. SimpleHandler
middleware
SimpleHandler
middleware
, / middleware
( ).
.
2.1.2.1. middleware
@web.middleware
async def middleware(self, request: web.Request, handler: Callable):
""" middleware json-.
"""
if not self.is_json_service_handler(request, handler):
return await handler(request)
try:
request_body = await self.get_request_body(request, handler)
except Exception as error:
response_body = self.get_error_body(request, error)
status = 400
else:
#
response_body, status = await self.get_response_body_and_status(
request, handler, request_body
)
finally:
# python (
# response_body) json.
text, status = await self.get_response_text_and_status(
request, response_body, status
)
return web.Response(
text=text, status=status, content_type="application/json",
)
middlewares
.
, :
... app = web.Application() service_handler = SimpleHandler() app.middlewares.append(service_handler.middleware) ...
2.1.2.2.
json , , , ( 400), ( 500), json.
"" :
def get_error_body(self, request: web.Request, error: Exception) -> dict:
""" .
"""
return {"error_type": str(type(error)), "error_message": str(error)}
, , json. , json .
2.1.2.3.
:
async def run_handler(
self, request: web.Request, handler: Callable, request_body: Any
) -> Any:
""" , .
"""
return await handler(request, request_body)
, / .
2.1.3.
:
async def some_handler(request: web.Request, data: dict) -> dict:
return data
url .
2.1.3.1. Responder con código 200
Solicitud POST
de /some_handler
:
{ "name": "test", "age": 25 }
... como se esperaba, devolverá una respuesta con el código 200:
{ "name": "test", "age": 25 }
2.1.3.2. Responder con el código 400
Cometemos un error en el cuerpo de la solicitud.
Solicitud POST
de /some_handler
:
{ "name": "test", 111111111111 "age": 25 }
:
{ "error_type": "<class 'json.decoder.JSONDecodeError'>", "error_message": "Expecting property name enclosed in double quotes: line 2 column 21 (char 22)" }
2.1.3.3. 500
( ).
async def handler500(request: web.Request, data: dict) -> dict:
raise Exception(" 500")
return data
POST
/handler500
:
{ "name": "test", "age": 25 }
:
{ "error_type": "<class 'Exception'>", "error_message": " 500" }
2.2. middleware "kwargs-"
middleware
.
.
:
async def some_handler(request: web.Request, data: dict) -> dict:
storage = request.app["storage"]
logger = request.app["logger"]
user_id = request.match_info["user_id"]
# .. ....
return data
storage
, logger
( - ), , "" .
2.2.1.
, , , :
async def some_handler_1(data: dict) -> int:
# ...
return some_data
async def some_handler_2(storage: StorageClass, data: List[int]) -> dict:
# ...
return some_data
async def some_handler_3(
data: Union[dict, List[str]], logger: LoggerClass, request: web.Request
) -> str:
# ...
return some_data
, .
2.2.2. ArgumentsManager
middleware
, "" "" .
, "" ArgumentsManager
. middlewares/utils.py
( ).
" " — " " , " ", — , " ".
, :
@dataclass
class RawDataForArgument:
request: web.Request
request_body: Any
arg_name: Optional[str] = None
class ArgumentsManager:
""" .
,
.
"""
def __init__(self) -> None:
self.getters: Dict[str, Callable] = {}
# json ------------------------------------------------------
def reg_request_body(self, arg_name) -> None:
""" .
"""
self.getters[arg_name] = self.get_request_body
def get_request_body(self, raw_data: RawDataForArgument):
return raw_data.request_body
# request --------------------------------------------------------
def reg_request_key(self, arg_name) -> None:
""" request.
"""
self.getters[arg_name] = self.get_request_key
def get_request_key(self, raw_data: RawDataForArgument):
return raw_data.request[raw_data.arg_name]
# request.app ----------------------------------------------------
def reg_app_key(self, arg_name) -> None:
""" app.
"""
self.getters[arg_name] = self.get_app_key
def get_app_key(self, raw_data: RawDataForArgument):
return raw_data.request.app[raw_data.arg_name]
# ------------------------------------------------------
def reg_match_info_key(self, arg_name) -> None:
""" .
"""
self.getters[arg_name] = self.get_match_info_key
def get_match_info_key(self, raw_data: RawDataForArgument):
return raw_data.request.match_info[raw_data.arg_name]
# ...
web.Application()
:
# ...
app = web.Application()
arguments_manager = ArgumentsManager()
# ,
# json-
arguments_manager.reg_request_body("data")
# ,
# request.match_info
arguments_manager.reg_match_info_key("info_id")
#
# ( " " )
app["storage"] = SomeStorageClass(login="user", password="123")
# ,
#
arguments_manager.reg_app_key("storage")
# ...
ArgumentsManager
. middleware
:
... service_handler = KwargsHandler(arguments_manager=arguments_manager) app.middlewares.append(service_handler.middleware) ...
. , , … , , .
2.2.3. KwargsHandler
middleware
KwargsHandler
SimpleHandler
, .2.2.1.
— run_handler
, — make_handler_kwargs
build_error_message_for_invalid_handler_argument
( ).
2.2.3.1.
:
async def run_handler(
self, request: web.Request, handler: Callable, request_body: Any
) -> Any:
""" , .
( ,
//)
"""
kwargs = self.make_handler_kwargs(request, handler, request_body)
return await handler(**kwargs)
, . , . .
2.2.3.2.
make_handler_kwargs
. , . ArgumentsManager
.
, , ArgumentsManager
.
. , web.Request
, web.Request
(, r: web.Request
req: web.Request
request: web.Request
). , web.Request
"" , .
: .
build_error_message_for_invalid_handler_argument
— . .
2.2.4.
:
async def create(
data: Union[dict, List[dict]], storage: dict,
) -> Union[dict, List[dict]]:
# ...
async def read(storage: dict, data: str) -> dict:
# ...
async def info(info_id: int, request: web.Request) -> str:
# ...
POST
, — GET
(, )
2.2.4.1. /create
:
[ { "name": "Ivan" }, { "name": "Oleg" } ]
:
[ { "id": "5730bab1-9c1b-4b01-9979-9ad640ea5fc1", "name": "Ivan" }, { "id": "976d821a-e871-41b4-b5a2-2875795d6166", "name": "Oleg" } ]
2.2.4.2. /read
:
"5730bab1-9c1b-4b01-9979-9ad640ea5fc1"
:
{ "id": "5730bab1-9c1b-4b01-9979-9ad640ea5fc1", "name": "Ivan" }
: UUID
, 500
— PersonNotFound
.
2.2.4.3. /info/{info_id}
GET
/info/123
:
"any json"
:
"info_id=123 and request=<Request GET /info/123 >"
2.3. middleware c /
, api- .
, create
:
{ "data": [ { "name": "Ivan" }, { "name": "Oleg" } ], "id": 11 }
:
{ "success": true, "result": [ { "id": "9738d8b8-69da-40b2-8811-b33652f92f1d", "name": "Ivan" }, { "id": "df0fdd43-4adc-43cd-ac17-66534529d440", "name": "Oleg" } ], "id": 11 }
, data
result
.
id
, .
success
.
, :
read
:
{ "data": "ddb0f2b1-0179-44b7-b94d-eb2f3b69292d", "id": 3 }
:
{ "success": false, "result": { "error_type": "<class 'handlers.PersonNotFound'>", "error_message": "Person whith id=ddb0f2b1-0179-44b7-b94d-eb2f3b69292d not found!" }, "id": 3 }
json middleware
middleware
. run_handler
, ( ) get_error_body
.
, "" , ( data
). ( result
). middleware
.
, , .
" ", . .
2.3.1. pydantic.BaseModel
pydantic.BaseModel
.
( ). — .
:
from pydantic import BaseModel
from typing import Union, List
class Info(BaseModel):
foo: int
class Person(BaseModel):
name: str
info: Union[Info, List[Info]]
kwargs = {"name": "Ivan", "info": {"foo": 0}}
person = Person(**kwargs)
assert person.info.foo == 0
kwargs = {"name": "Ivan", "info": [{"foo": 0}, {"foo": 1}]}
person = Person(**kwargs)
assert person.info[1].foo == 1
kwargs = {"name": "Ivan", "info": {"foo": "bar"}} # <- , str int
person = Person(**kwargs)
# :
# ...
# pydantic.error_wrappers.ValidationError: 2 validation errors for Person
# info -> foo
# value is not a valid integer (type=type_error.integer)
# info
# value is not a valid list (type=type_error.list)
, , . , , .
typing
.
- pydantic.BaseModel
, "" ( … , "" — ).
. , : info.foo
int
, info
list
, .
pydantic.BaseModel
, .
2.3.1.1.
, , :
kwargs = {"name": "Ivan", "info": {"foo": "0"}}
person = Person(**kwargs)
assert person.info.foo == 0
, , , UUID
-> UUID
. , , , Strict...
. , pydantic.StrictInt
, pydantic.StrictStr
, ....
2.3.1.2.
, , :
kwargs = {"name": "Ivan", "info": {"foo": 0}, "bar": "BAR"}
person = Person(**kwargs)
.
, .
, , :
from pydantic import BaseModel, Extra, StrictInt, StrictStr
from typing import Union, List
class BaseApi(BaseModel):
class Config:
# (ignore), (allow)
# (forbid)
# , :
# https://pydantic-docs.helpmanual.io/usage/model_config/
extra = Extra.forbid
class Info(BaseApi):
foo: StrictInt
class Person(BaseApi):
name: StrictStr
info: Union[Info, List[Info]]
kwargs = {"name": "Ivan", "info": {"foo": 0}, "bar": "BAR"}
person = Person(**kwargs)
# ...
# pydantic.error_wrappers.ValidationError: 1 validation error for Person
# bar
# extra fields not permitted (type=value_error.extra)
— , .
2.3.2. valdec.validate
valdec.validate / .
, .
, None
( -> None:
).
/:
from valdec.decorators import validate
@validate # ,
def foo(i: int, s: str) -> int:
return i
@validate("i", "s") # "i" "s"
def bar(i: int, s: str) -> int:
return i
… .
#
from valdec.decorators import async_validate as validate
@validate("s", "return", exclude=True) # "i"
async def foo(i: int, s: str) -> int:
return int(i)
@validate("return") #
async def bar(i: int, s: str) -> int:
return int(i)
2.3.2.1. -
/ , - ( , ), , , .
-:
def validator(
annotations: Dict[str, Any],
values: Dict[str, Any],
is_replace: bool,
extra: dict
) -> Optional[Dict[str, Any]]:
:
annotations
— , .values
— , .is_replace
— , -, — .
-
True
, . , ,BaseModel
,BaseModel
, " ". -
False
,None
, ( , , ,BaseModel
).
-
extra
— .
, validate
- pydantic.BaseModel
.
:
- (
pydantic.BaseModel
) - . .
- ( ), ,
is_replace
.
, , , . , , , .
- ( valdec
ValidatedDC
). : , pydantic.BaseModel
. , , "" .
2.3.2.2.
, "" :
from typing import List, Optional
from pydantic import BaseModel, StrictInt, StrictStr
from valdec.decorators import validate
class Profile(BaseModel):
age: StrictInt
city: StrictStr
class Student(BaseModel):
name: StrictStr
profile: Profile
@validate("group")
def func(group: Optional[List[Student]] = None):
for student in group:
assert isinstance(student, Student)
assert isinstance(student.name, str)
assert isinstance(student.profile.age, int)
data = [
{"name": "Peter", "profile": {"age": 22, "city": "Samara"}},
{"name": "Elena", "profile": {"age": 20, "city": "Kazan"}},
]
func(data)
assert'
.
:
@validate #
def func(group: Optional[List[Student]] = None, i: int) -> List[Student]:
#...
return [
{"name": "Peter", "profile": {"age": 22, "city": "Samara"}},
{"name": "Elena", "profile": {"age": 20, "city": "Kazan"}},
]
, , return
, Student
( ).
… . , , (, , ). :
from valdec.data_classes import Settings
from valdec.decorators import validate as _validate
from valdec.validator_pydantic import validator
custom_settings = Settings(
validator=validator, # -.
is_replace_args=False, #
is_replace_result=False, #
extra={} # ,
# -
)
#
def validate_without_replacement(*args, **kwargs):
kwargs["settings"] = custom_settings
return _validate(*args, **kwargs)
#
@validate_without_replacement
def func(group: Optional[List[Student]] = None, i: int) -> List[Student]:
#...
return [
{"name": "Peter", "profile": {"age": 22, "city": "Samara"}},
{"name": "Elena", "profile": {"age": 20, "city": "Kazan"}},
]
func
, is_replace_result=False
. , is_replace_args=False
.
, .
— , , "" . , . , .
— , , , , ? — .
, -, — .
2.3.2.3.
:
from valdec.decorators import validate
@validate
def foo(i: int):
assert isinstance(i, int)
foo("1")
. , .
, , validate
, - pydantic.BaseModel
. .2.3.1.1. .
, ( ), :
from valdec.decorators import validate
from pydantic import StrictInt
@validate
def foo(i: StrictInt):
pass
foo("1")
# ...
# valdec.errors.ValidationArgumentsError: Validation error
# <class 'valdec.errors.ValidationError'>: 1 validation error for
# argument with the name of:
# i
# value is not a valid integer (type=type_error.integer).
: , .
.
2.3.2.4.
valdec.errors.ValidationArgumentsError
— ""valdec.errors.ValidationReturnError
—
. pydantic.BaseModel
.
2.3.3.
, - pydantic.BaseModel
.
C :
data_classes/base.py
from pydantic import BaseModel, Extra
class BaseApi(BaseModel):
""" api.
"""
class Config:
extra = Extra.forbid
2.3.4.
middleware, , , , :
from typing import List, Union
from valdec.decorators import async_validate as validate
from data_classes.person import PersonCreate, PersonInfo
@validate("data", "return")
async def create(
data: Union[PersonCreate, List[PersonCreate]], storage: dict,
) -> Union[PersonInfo, List[PersonInfo]]:
# ...
return result
( ):
-
validate
, "" - .
/ , .
: web.Request()
, , wep.Aplication()
. , , - , web.Request()
.
, :
data_classes/person.py
from uuid import UUID
from pydantic import Field, StrictStr
from data_classes.base import BaseApi
class PersonCreate(BaseApi):
""" .
"""
name: StrictStr = Field(description=".", example="Oleg")
class PersonInfo(BaseApi):
""" .
"""
id: UUID = Field(description=".")
name: StrictStr = Field(description=".")
2.3.5.
.2.3. .
.
data_classes/wraps.py
from typing import Any, Optional
from pydantic import Field, StrictInt
from data_classes.base import BaseApi
_ID_DESCRIPTION = " ."
class WrapRequest(BaseApi):
""" .
"""
data: Any = Field(description=" .", default=None)
id: Optional[StrictInt] = Field(description=_ID_DESCRIPTION)
class WrapResponse(BaseApi):
""" .
"""
success: bool = Field(description=" .", default=True)
result: Any = Field(description=" .")
id: Optional[StrictInt] = Field(description=_ID_DESCRIPTION)
middleware
.
2.3.6. WrapsKwargsHandler
middleware
WrapsKwargsHandler
KwargsHandler
, ( ).
— run_handler
get_error_body
.
2.3.6.1.
:
async def run_handler(
self, request: web.Request, handler: Callable, request_body: Any
) -> dict:
id_ = None
try:
#
wrap_request = WrapRequest(**request_body)
except Exception as error:
message = f"{type(error).__name__} - {error}"
raise InputDataValidationError(message)
# id
id_ = wrap_request.id
request[KEY_NAME_FOR_ID] = id_
try:
result = await super().run_handler(
request, handler, wrap_request.data
)
except ValidationArgumentsError as error:
message = f"{type(error).__name__} - {error}"
raise InputDataValidationError(message)
#
wrap_response = WrapResponse(success=True, result=result, id=id_)
return wrap_response.dict()
. InputDataValidationError
:
- ( )
-
data
id
-
id
StrictInt
None
id
, wrap_request.id
None
. data
. , , wrap_request.data
None
.
wrap_request.id
request
. ( ).
, wrap_request.data
(, wrap_request.data
python , json). , InputDataValidationError
valdec.errors.ValidationArgumentsError
.
, , WrapResponse
.
, . wrap_response
, ( ). , , , , , BaseApi
. , json. , "" WrapResponse.result
wrap_response
wrap_response.dict()
( ).
2.3.6.2.
:
def get_error_body(self, request: web.Request, error: Exception) -> dict:
""" .
"""
result = dict(error_type=str(type(error)), error_message=str(error))
# ,
# ""
response = dict(
# id request .
success=False, result=result, id=request.get(KEY_NAME_FOR_ID)
)
return response
( super()
result
), . .
2.3.7.
:
@validate("data", "return")
async def create(
data: Union[PersonCreate, List[PersonCreate]], storage: dict,
) -> Union[PersonInfo, List[PersonInfo]]:
# ...
@validate("data", "return")
async def read(storage: dict, req: web.Request, data: UUID) -> PersonInfo:
# ...
@validate("info_id")
async def info(info_id: int, request: web.Request) -> Any:
return f"info_id={info_id} and request={request}"
POST , — GET (, )
2.3.7.1. /create
- №1:
{ "data": [ { "name": "Ivan" }, { "name": "Oleg" } ], "id": 1 }
:
{ "success": true, "result": [ { "id": "af908a90-9157-4231-89f6-560eb6a8c4c0", "name": "Ivan" }, { "id": "f7d554a0-1be9-4a65-bfc2-b89dbf70bb3c", "name": "Oleg" } ], "id": 1 }
- №2:
{ "data": { "name": "Eliza" }, "id": 2 }
:
{ "success": true, "result": { "id": "f3a45a19-acd0-4939-8e0c-e10743ff8e55", "name": "Eliza" }, "id": 2 }
- №3:
data
{ "data": 123, "id": 3 }
:
{ "success": false, "result": { "error_type": "<class 'middlewares.exceptions.InputDataValidationError'>", "error_message": "ValidationArgumentsError - Validation error <class 'valdec.errors.ValidationError'>: 2 validation errors for argument with the name of:\ndata\n value is not a valid dict (type=type_error.dict)\ndata\n value is not a valid list (type=type_error.list)." }, "id": 3 }
2.3.7.2. /read
- №1:
{ "data": "f3a45a19-acd0-4939-8e0c-e10743ff8e55", "id": 4 }
:
{ "success": true, "result": { "id": "f3a45a19-acd0-4939-8e0c-e10743ff8e55", "name": "Eliza" }, "id": 4
- №2:
.
{ "some_key": "f3a45a19-acd0-4939-8e0c-e10743ff8e55", "id": 5 }
:
{ "success": false, "result": { "error_type": "<class 'middlewares.exceptions.InputDataValidationError'>", "error_message": "ValidationError - 1 validation error for WrapRequest\nsome_key\n extra fields not permitted (type=value_error.extra)" }, "id": null }
2.3.7.3. /info/{info_id}
-
GET
/info/123
:
{}
:
{ "success": true, "result": "info_id=123 and request=<Request GET /info/123 >", "id": null }
3.
, WrapsKwargsHandler
, , . . pydantic.BaseModel
json-schema, ( , : swagger-, json- ).
. . , swagger
aiohttp
, ( ).
, aiohttp-swagger
( ), Union
.
aiohttp-swagger3
, , , sub_app
.
- , , , - , — .
4.
json middleware . . .
Puede crear envoltorios para el contenido de solicitudes y respuestas. Además, puede personalizar la validación de manera flexible y aplicarla solo donde realmente se necesite.
No tengo ninguna duda de que los ejemplos que he propuesto se pueden implementar de otra manera. Pero espero que mis soluciones, si no del todo útiles, contribuyan a encontrar otras más adecuadas.
Gracias por tu tiempo. Estaría encantado de recibir comentarios y aclaraciones.
Usó MarkConv al publicar el artículo