the key does not exist in the form attribute? In that case a special KeyError is raised. You can catch it like a standard KeyError but if you don’t do that, a HTTP 400 Bad Request error page is shown instead very generic base classes such as HTTPException or even Exception. However, be aware that these will catch more than you might expect. An error handler for HTTPException might be useful for turning the default some options in order to use your favorite debugger: • debug - whether to enable debug mode and catch exceptions • use_debugger - whether to use the internal Flask debugger • use_reloader - whether

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle class flask_restful.Api(app=None, prefix=’‘, default_mediatype=’application/json’, deco- rators=None, catch_all_404s=False, serve_challenge_on_401=False, url_part_order=’bae’, errors=None) The main entry point The default media type to return • decorators (list) – Decorators to attach to every resource • catch_all_404s (bool) – Use handle_error() to handle 404 errors throughout your app 28 Chapter 2. API Reference

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle class flask_restful.Api(app=None, prefix='', default_mediatype='application/json', decorators=None, catch_all_404s=False, serve_challenge_on_401=False, url_part_order='bae', errors=None) The main entry point (str) – The default media type to return decorators (list) – Decorators to attach to every resource catch_all_404s (bool) – Use handle_error() to handle 404 errors throughout your app serve_challenge_on_401

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle class flask_restful.Api(app=None, prefix=”, default_mediatype=’application/json’, decora- tors=None, catch_all_404s=False, serve_challenge_on_401=False, url_part_order=’bae’, errors=None) The main entry point The default media type to return • decorators (list) – Decorators to attach to every resource • catch_all_404s (bool) – Use handle_error() to handle 404 errors throughout your app 28 Chapter 2. API Reference

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle class flask_restful.Api(app=None, prefix=”, default_mediatype=’application/json’, decora- tors=None, catch_all_404s=False, serve_challenge_on_401=False, url_part_order=’bae’, errors=None) The main entry point The default media type to return • decorators (list) – Decorators to attach to every resource • catch_all_404s (bool) – Use handle_error() to handle 404 errors throughout your app 28 Chapter 2. API Reference

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle class flask_restful.Api(app=None, prefix='', default_mediatype='application/json', decorators=None, catch_all_404s=False, serve_challenge_on_401=False, url_part_order='bae', errors=None) The main entry point [https://docs.python.org/3/library/stdtypes.html#list]) – Decorators to attach to every resource catch_all_404s (bool [https://docs.python.org/3/library/functions.html#bool]) – Use handle_error() to handle

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle class flask_restful.Api(app=None, prefix='', default_mediatype='application/json', decorators=None, catch_all_404s=False, serve_challenge_on_401=False, url_part_order='bae', errors=None) The main entry point [https://docs.python.org/3/library/stdtypes.html#list]) – Decorators to attach to every resource catch_all_404s (bool [https://docs.python.org/3/library/functions.html#bool]) – Use handle_error() to handle

special KeyError [https://docs.python.org/3/library/exceptions.html#KeyError] is raised. You can catch it like a standard KeyError [https://docs.python.org/3/library/exceptions.html#KeyError] but if you very generic base classes such as HTTPException or even Exception. However, be aware that these will catch more than you might expect. An error handler for HTTPException might be useful for turning the default set some options in order to use your favorite debugger: debug - whether to enable debug mode and catch exceptions use_debugger - whether to use the internal Flask debugger use_reloader - whether to reload

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle

on 404 Not Found errors; in which case, use the catch_all_404s parameter of the Api constructor. app = Flask(__name__) api = flask_restful.Api(app, catch_all_404s=True) Then Flask-RESTful will handle