python - python-flask处理应用程序错误

Question

我建立了一个Flask应用程序，然后尝试使用errorhandler装饰器从路由中捕获未处理的应用程序错误。

我有一个main.py看起来像这样，

app = Flask(__name__)
api = Api(app)

api.add_resource(Ping, '/ping')

@app.errorhandler(500)
def internal_server_error(error):
    print "caught internal server error"
    return "This page does not exist", 500

路由Ping在另一个文件中，这是该文件的示例版本

class Ping(Resource):
    def get(self):

        raise
        return {}, 200

我提出了加薪尝试并重现500内部服务器错误。这是我的应用程序引发的示例错误

[2019-01-26 10:37:36,449] ERROR in app: Exception on /events/v1/monitoring/ping [GET]
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/lib64/python2.7/site-packages/flask_restful/__init__.py", line 480, in wrapper
    resp = resource(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/flask/views.py", line 88, in view
    return self.dispatch_request(*args, **kwargs)
  File "/usr/local/lib64/python2.7/site-packages/flask_restful/__init__.py", line 595, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/myapi/ping.py", line 17, in get
    raise
TypeError: exceptions must be old-style classes or derived from BaseException, not NoneType
127.0.0.1 - - [26/Jan/2019 10:37:36] "GET /ping HTTP/1.0" 500 -

由于我无法弄清的原因，@ app.errorhandler装饰器无法捕获应用程序引发的任何500个错误。

Answer 1

我认为您正在使用 flask 不动。为了捕获错误处理程序，您应该在配置文件中将config参数PROPAGATE_EXCEPTIONS设置为True。

Flask restful有自己的错误处理程序，与Flask的错误处理程序不同。这是摘录:

[...]

if not isinstance(e, HTTPException) and current_app.propagate_exceptions:
    exc_type, exc_value, tb = sys.exc_info()
    if exc_value is e:
        raise
    else:
        raise e

headers = Headers()
if isinstance(e, HTTPException):
    code = e.code
    default_data = {
        'message': getattr(e, 'description', http_status_message(code))
    }
    headers = e.get_response().headers
else:
    code = 500
    default_data = {
        'message': http_status_message(code),
    }
[...]

将 PROPAGATE_EXCEPTIONS设置为 True之后，您应该至少添加以下两个错误处理程序:

@app.errorhandler(Exception)
def internal_server_error(e):
    return jsonify({'msg': 'Internal server error'}), 500

@app.errorhandler(500)
def internal_server_error_500(e):
    return jsonify({'msg': 'Internal server error'}), 500

因此，第一个将捕获在应用程序级别引发的任何异常，甚至是您自己的自定义异常，第二个将捕获任何500个错误，例如在 abort(500)上引发。