python - 验证参数时 webargs 出现异常

Question

最近在使用webargs(8.0.1)和flask-restful(0.3.8)时遇到了一些问题

当我尝试使用cURL http://127.0.0.1:5001/?score=100A

时，异常抛出两次

我认为它应该使用函数 handle_request_parsing_error 返回 jsonfy 错误消息，但它只返回 HTTP 500 错误。

希望有人能帮我解决这个问题，非常感谢

from flask import Flask
from flask_restful import Api, Resource

from webargs import fields, validate
from webargs.flaskparser import use_args, use_kwargs, parser, abort

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


class ScoreResource(Resource):
    """A welcome page."""

    score_args = {"score": fields.Int(required=True)}

    @use_args(score_args, location="query")
    def get(self, args):
        return {"message": "You score is {}!".format(args["score"])}


# This error handler is necessary for usage with Flask-RESTful
@parser.error_handler
def handle_request_parsing_error(err, req, schema):
    """webargs error handler that uses Flask-RESTful's abort function to return
    a JSON error response to the client.
    """
    abort(422, errors=err.messages)


if __name__ == "__main__":
    api.add_resource(ScoreResource, "/")
    app.run(port=5001, debug=True)

127.0.0.1 - - [10/Sep/2021 18:05:33] "GET /?score=100A HTTP/1.1" 500 -
Traceback (most recent call last):
  File "E:\projects\tools\venv\lib\site-packages\webargs\core.py", line 328, in parse
    data = schema.load(preprocessed_data, **load_kwargs)
  File "E:\projects\tools\venv\lib\site-packages\marshmallow\schema.py", line 720, in load
    data, many=many, partial=partial, unknown=unknown, postprocess=True
  File "E:\projects\tools\venv\lib\site-packages\marshmallow\schema.py", line 901, in _do_load
    raise exc
marshmallow.exceptions.ValidationError: {'score': ['Not a valid integer.']}
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 2464, in __call__
    return self.wsgi_app(environ, start_response)
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 2450, in wsgi_app
    response = self.handle_exception(e)
  File "E:\projects\tools\venv\lib\site-packages\flask_restful\__init__.py", line 272, in error_router
    return original_handler(e)
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 1867, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "E:\projects\tools\venv\lib\site-packages\flask\_compat.py", line 38, in reraise
    raise value.with_traceback(tb)
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "E:\projects\tools\venv\lib\site-packages\flask_restful\__init__.py", line 272, in error_router
    return original_handler(e)
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "E:\projects\tools\venv\lib\site-packages\flask\_compat.py", line 38, in reraise
    raise value.with_traceback(tb)
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "E:\projects\tools\venv\lib\site-packages\flask\app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "E:\projects\tools\venv\lib\site-packages\flask_restful\__init__.py", line 468, in wrapper
    resp = resource(*args, **kwargs)
  File "E:\projects\tools\venv\lib\site-packages\flask\views.py", line 89, in view
    return self.dispatch_request(*args, **kwargs)
  File "E:\projects\tools\venv\lib\site-packages\flask_restful\__init__.py", line 583, in dispatch_request
    resp = meth(*args, **kwargs)
  File "E:\projects\tools\venv\lib\site-packages\webargs\core.py", line 445, in wrapper
    error_headers=error_headers,
  File "E:\projects\tools\venv\lib\site-packages\webargs\core.py", line 337, in parse
    error_headers=error_headers,
  File "E:\projects\tools\venv\lib\site-packages\webargs\core.py", line 236, in _on_validation_error
    error_headers=error_headers,
TypeError: handle_request_parsing_error() got an unexpected keyword argument 'error_status_code'

Answer 1

您只需注册一个 Flask 错误处理程序即可将错误格式化为 json。
查看Framework Support文档中的部分。

from flask import Flask
from flask import jsonify
from flask_restful import Api, Resource

from webargs import fields, validate
from webargs.flaskparser import use_args, use_kwargs, parser, abort

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

class ScoreResource(Resource):
    """A welcome page."""

    score_args = {"score": fields.Int(required=True)}

    @use_args(score_args, location="query")
    def get(self, args):
        return {"message": "You score is {}!".format(args["score"])}

@app.errorhandler(422)
@app.errorhandler(400)
def handle_error(err):
    headers = err.data.get("headers", None)
    messages = err.data.get("messages", ["Invalid request."])
    if headers:
        return jsonify({"errors": messages}), err.code, headers
    else:
        return jsonify({"errors": messages}), err.code


if __name__ == "__main__":
    api.add_resource(ScoreResource, "/")
    app.run(port=5001, debug=True)