如何使用Connexion处理AioHttp上的错误

问题描述

我想在我的python网络api中使用AioHttp和Connexion处理错误，就像Flask通过@app.errorhandler(Exception)所做的一样

换句话说，假设我的服务引发了SomethingalreadyExists，并且我想返回409冲突，而不是在我的所有api中添加以下代码：

try:
  myservice.create_something(..)
except SomethingalreadyExists as error:     # Repeated code -> DRY
  return json_response({"message": str(error)},status=409)

我只想在API层中调用myservice.create_something(..)，错误处理将为SomethingalreadyExists异常返回409或为SomethingNotFound返回404。

注意： 在Flask土地上，如下图所示：

import connexion


def create_api_app(version='api'):
    connexion_app = connexion.FlaskApp(__name__,specification_dir='../api/')
    connexion_app.add_api('openapi.yaml',validate_responses=True)
    app = connexion_app.app

    # It intercepts the specific exception and returns the respective status_code
    @app.errorhandler(InvalidValueException)
    def bad_request_handler(error):
        return 'Bad Request: {}'.format(str(error)),400

    @app.errorhandler(NotFoundException)
    def not_found_handler(error):
        return 'Not found: {}'.format(str(error)),404

    @app.errorhandler(AlreadyExistsException)
    def conflict_handler(error):
        return 'Conflict: {}'.format(str(error)),409


# my_service.py
def get_model(i):

    model = get_model_or_none(id)
    if btask is None:
        raise NotFoundException(f"Model id:{id} not found.")
    ...

# api.py
def get_model(id):
    model = my_service.get_model(id)
    # handle errors not required ;)
    return btask.to_dict()

我想在我的AioHttp连接应用程序中做同样的事情：

from connexion import AioHttpApp


def create_app():
    connexion_app = AioHttpApp(__name__,port=8000,specification_dir="../",only_one_api=True)
    connexion_app.add_api("openapi.yaml",pass_context_arg_name="request")

    # Do something here.. like
    # web.Application(middlewares=[handle_already_exists_errors]) --> doesn't work
    # OR
    # connex_app.add_error_handler(
    #       AlreadyExistsException,handle_already_exists_errors) --> doesn't work too 
    return connexion_app

干杯，我将不胜感激！

罗杰

解决方法

我正在研究connexion和aiohttp代码，并找到了一种使用中间件的方法：

import json
from aiohttp.web import middleware
from connexion.lifecycle import ConnexionResponse
from connexion import AioHttpApp
from .exceptions import NotFoundException,AlreadyExistsException


def create_app():
    connexion_app = AioHttpApp(
        __name__,port=8000,specification_dir="../",only_one_api=True
    )
    connexion_app.add_api("openapi.yaml",pass_context_arg_name="request")
    connexion_app.app.middlewares.append(errors_handler_middleware)
    return connexion_app


@middleware
async def errors_handler_middleware(request,handler):
    """ Handle standard errors returning response following the connexion style messages"""
    try:
        response = await handler(request)
        return response

    except NotFoundException as error:
        return json_error(message=str(error),title='Not Found',status_code=404)
    except AlreadyExistsException as error:
        return json_error(message=str(error),title='Conflict',status_code=409)


def json_error(message,title,status_code):
    return ConnexionResponse(
        body=json.dumps({
            'title': title,'detail': message,'status': status_code,}).encode('utf-8'),status_code=status_code,content_type='application/json'
    )