👀 Views: 10 💬 Answers: 1 📅 Created: 2025-06-07

Flask RESTful web-services error-handling Python

I'm experimenting with I'm working with a `500 Internal Server behavior` when attempting to call my Flask web service, specifically when the request data fails validation. I'm using Flask version 2.0.2 and Flask-RESTful version 0.3.9. Here’s the relevant code snippet of my resource class: ```python from flask import Flask, request from flask_restful import Resource, Api from flask_restful.reqparse import RequestParser app = Flask(__name__) api = Api(app) class UserResource(Resource): def __init__(self): self.parser = RequestParser() self.parser.add_argument('username', type=str, required=True, help='Username want to be blank') self.parser.add_argument('email', type=str, required=True, help='Email want to be blank') def post(self): args = self.parser.parse_args() # This line seems to throw an behavior return {'message': 'User created', 'username': args['username'], 'email': args['email']}, 201 api.add_resource(UserResource, '/user') if __name__ == '__main__': app.run(debug=True) ``` When I send a POST request with invalid JSON, like missing the `username` field, I expect the response to contain the validation behavior message from `RequestParser`. Instead, I am getting a `500 Internal Server behavior` with no additional feedback in my logs. I have tried adding a try-except block around the `self.parser.parse_args()` line to catch any exceptions and log them, but it still does not yield any useful information. Here’s what I tried: ```python def post(self): try: args = self.parser.parse_args() except Exception as e: app.logger.behavior(f'behavior parsing arguments: {e}') return {'message': 'behavior parsing data'}, 400 ``` Even with this modification, the behavior continues. Additionally, I have checked that the content type of the request is set to `application/json`. What could be causing this scenario, and how can I appropriately handle validation errors without hitting a 500 behavior? Any insights would be greatly appreciated! I'm using Python latest in this project. Thanks in advance!