1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
.. _errors:
Error Handling
==============
.. contents:: :local:
When it comes to error handling, you can always directly set the error
status, appropriate response headers, and error body using the ``resp``
object. However, Falcon tries to make things a little easier by
providing a set of error classes you can raise when something goes
wrong. All of these classes inherit from :class:`~.HTTPError`.
Falcon will convert any instance or subclass of :class:`~.HTTPError`
raised by a responder, hook, or middleware component into an appropriate
HTTP response. The default error serializer supports both JSON and XML.
If the client indicates acceptance of both JSON and XML with equal
weight, JSON will be chosen. Other media types may be supported by
overriding the default serializer via
:meth:`~.App.set_error_serializer`.
.. note::
If a custom media type is used and the type includes a "+json" or
"+xml" suffix, the default serializer will convert the error to JSON
or XML, respectively.
To customize what data is passed to the serializer, subclass
:class:`~.HTTPError` or any of its child classes, and override the
:meth:`~.HTTPError.to_dict` method. To also support XML, override the
:meth:`~.HTTPError.to_xml` method. For example::
class HTTPNotAcceptable(falcon.HTTPNotAcceptable):
def __init__(self, acceptable):
description = (
'Please see "acceptable" for a list of media types '
'and profiles that are currently supported.'
)
super().__init__(description=description)
self._acceptable = acceptable
def to_dict(self, obj_type=dict):
result = super().to_dict(obj_type)
result['acceptable'] = self._acceptable
return result
All classes are available directly in the ``falcon`` package namespace:
.. tabs::
.. tab:: WSGI
.. code:: python
import falcon
class MessageResource:
def on_get(self, req, resp):
# -- snip --
raise falcon.HTTPBadRequest(
title="TTL Out of Range",
description="The message's TTL must be between 60 and 300 seconds, inclusive."
)
# -- snip --
.. tab:: ASGI
.. code:: python
import falcon
class MessageResource:
async def on_get(self, req, resp):
# -- snip --
raise falcon.HTTPBadRequest(
title="TTL Out of Range",
description="The message's TTL must be between 60 and 300 seconds, inclusive."
)
# -- snip --
Note also that any exception (not just instances of
:class:`~.HTTPError`) can be caught, logged, and otherwise handled
at the global level by registering one or more custom error handlers.
See also :meth:`~.falcon.App.add_error_handler` to learn more about this
feature.
.. note::
By default, any uncaught exceptions will return an HTTP 500 response and
log details of the exception to ``wsgi.errors``.
Base Class
----------
.. autoclass:: falcon.HTTPError
:members:
.. _predefined_errors:
Predefined Errors
-----------------
.. autoclass:: falcon.HTTPBadRequest
:members:
.. autoclass:: falcon.HTTPInvalidHeader
:members:
.. autoclass:: falcon.HTTPMissingHeader
:members:
.. autoclass:: falcon.HTTPInvalidParam
:members:
.. autoclass:: falcon.HTTPMissingParam
:members:
.. autoclass:: falcon.HTTPUnauthorized
:members:
.. autoclass:: falcon.HTTPForbidden
:members:
.. autoclass:: falcon.HTTPNotFound
:members:
.. autoclass:: falcon.HTTPRouteNotFound
:members:
.. autoclass:: falcon.HTTPMethodNotAllowed
:members:
.. autoclass:: falcon.HTTPNotAcceptable
:members:
.. autoclass:: falcon.HTTPConflict
:members:
.. autoclass:: falcon.HTTPGone
:members:
.. autoclass:: falcon.HTTPLengthRequired
:members:
.. autoclass:: falcon.HTTPPreconditionFailed
:members:
.. autoclass:: falcon.HTTPPayloadTooLarge
:members:
.. autoclass:: falcon.HTTPUriTooLong
:members:
.. autoclass:: falcon.HTTPUnsupportedMediaType
:members:
.. autoclass:: falcon.HTTPRangeNotSatisfiable
:members:
.. autoclass:: falcon.HTTPUnprocessableEntity
:members:
.. autoclass:: falcon.HTTPLocked
:members:
.. autoclass:: falcon.HTTPFailedDependency
:members:
.. autoclass:: falcon.HTTPPreconditionRequired
:members:
.. autoclass:: falcon.HTTPTooManyRequests
:members:
.. autoclass:: falcon.HTTPRequestHeaderFieldsTooLarge
:members:
.. autoclass:: falcon.HTTPUnavailableForLegalReasons
:members:
.. autoclass:: falcon.HTTPInternalServerError
:members:
.. autoclass:: falcon.HTTPNotImplemented
:members:
.. autoclass:: falcon.HTTPBadGateway
:members:
.. autoclass:: falcon.HTTPServiceUnavailable
:members:
.. autoclass:: falcon.HTTPGatewayTimeout
:members:
.. autoclass:: falcon.HTTPVersionNotSupported
:members:
.. autoclass:: falcon.HTTPInsufficientStorage
:members:
.. autoclass:: falcon.HTTPLoopDetected
:members:
.. autoclass:: falcon.HTTPNetworkAuthenticationRequired
:members:
.. autoclass:: falcon.MediaNotFoundError
:members:
.. autoclass:: falcon.MediaMalformedError
:members:
.. autoclass:: falcon.MediaValidationError
:members:
|
