Django Exceptions¶
Django raises some of its own exceptions as well as standard Python exceptions.
Django Core Exceptions¶
Django core exception classes are defined in django.core.exceptions
.
AppRegistryNotReady
¶
-
exception
AppRegistryNotReady
[source]¶ This exception is raised when attempting to use models before the app loading process, which initializes the ORM, is complete.
ObjectDoesNotExist
¶
-
exception
ObjectDoesNotExist
[source]¶ The base class for
DoesNotExist
exceptions; atry/except
forObjectDoesNotExist
will catchDoesNotExist
exceptions for all models.See
get()
for further information onObjectDoesNotExist
andDoesNotExist
.
FieldDoesNotExist
¶
MultipleObjectsReturned
¶
-
exception
MultipleObjectsReturned
[source]¶ The
MultipleObjectsReturned
exception is raised by a query if only one object is expected, but multiple objects are returned. A base version of this exception is provided indjango.core.exceptions
; each model class contains a subclassed version that can be used to identify the specific object type that has returned multiple objects.See
get()
for further information.
SuspiciousOperation
¶
-
exception
SuspiciousOperation
[source]¶ The
SuspiciousOperation
exception is raised when a user has performed an operation that should be considered suspicious from a security perspective, such as tampering with a session cookie. Subclasses ofSuspiciousOperation
include:DisallowedHost
DisallowedModelAdminLookup
DisallowedModelAdminToField
DisallowedRedirect
InvalidSessionKey
RequestDataTooBig
SuspiciousFileOperation
SuspiciousMultipartForm
SuspiciousSession
TooManyFieldsSent
If a
SuspiciousOperation
exception reaches the WSGI handler level it is logged at theError
level and results in aHttpResponseBadRequest
. See the logging documentation for more information.
PermissionDenied
¶
-
exception
PermissionDenied
[source]¶ The
PermissionDenied
exception is raised when a user does not have permission to perform the action requested.
ViewDoesNotExist
¶
-
exception
ViewDoesNotExist
[source]¶ The
ViewDoesNotExist
exception is raised bydjango.urls
when a requested view does not exist.
MiddlewareNotUsed
¶
-
exception
MiddlewareNotUsed
[source]¶ The
MiddlewareNotUsed
exception is raised when a middleware is not used in the server configuration.
ImproperlyConfigured
¶
-
exception
ImproperlyConfigured
[source]¶ The
ImproperlyConfigured
exception is raised when Django is somehow improperly configured – for example, if a value insettings.py
is incorrect or unparseable.
FieldError
¶
-
exception
FieldError
[source]¶ The
FieldError
exception is raised when there is a problem with a model field. This can happen for several reasons:- A field in a model clashes with a field of the same name from an abstract base class
- An infinite loop is caused by ordering
- A keyword cannot be parsed from the filter parameters
- A field cannot be determined from a keyword in the query parameters
- A join is not permitted on the specified field
- A field name is invalid
- A query contains invalid order_by arguments
ValidationError
¶
-
exception
ValidationError
[source]¶ The
ValidationError
exception is raised when data fails form or model field validation. For more information about validation, see Form and Field Validation, Model Field Validation and the Validator Reference.
URL Resolver exceptions¶
URL Resolver exceptions are defined in django.urls
.
Deprecated since version 1.10: In older versions, these exceptions are located in
django.core.urlresolvers
. Importing from the old location will continue
to work until Django 2.0.
Resolver404
¶
-
exception
Resolver404
[source]¶ The
Resolver404
exception is raised byresolve()
if the path passed toresolve()
doesn’t map to a view. It’s a subclass ofdjango.http.Http404
.
NoReverseMatch
¶
-
exception
NoReverseMatch
[source]¶ The
NoReverseMatch
exception is raised bydjango.urls
when a matching URL in your URLconf cannot be identified based on the parameters supplied.
Database Exceptions¶
Database exceptions may be imported from django.db
.
Django wraps the standard database exceptions so that your Django code has a guaranteed common implementation of these classes.
The Django wrappers for database exceptions behave exactly the same as the underlying database exceptions. See PEP 249, the Python Database API Specification v2.0, for further information.
As per PEP 3134, a __cause__
attribute is set with the original
(underlying) database exception, allowing access to any additional
information provided. (Note that this attribute is available under
both Python 2 and Python 3, although PEP 3134 normally only applies
to Python 3. To avoid unexpected differences with Python 3, Django will also
ensure that the exception made available via __cause__
has a usable
__traceback__
attribute.)
The __traceback__
attribute described above was added.
-
exception
models.
ProtectedError
¶
Raised to prevent deletion of referenced objects when using
django.db.models.PROTECT
. models.ProtectedError
is a subclass
of IntegrityError
.
Http Exceptions¶
Http exceptions may be imported from django.http
.
UnreadablePostError
¶
-
exception
UnreadablePostError
[source]¶ UnreadablePostError
is raised when a user cancels an upload.
Transaction Exceptions¶
Transaction exceptions are defined in django.db.transaction
.
TransactionManagementError
¶
-
exception
TransactionManagementError
[source]¶ TransactionManagementError
is raised for any and all problems related to database transactions.
Testing Framework Exceptions¶
Exceptions provided by the django.test
package.
RedirectCycleError
¶
-
exception
client.
RedirectCycleError
¶ RedirectCycleError
is raised when the test client detects a loop or an overly long chain of redirects.
Python Exceptions¶
Django raises built-in Python exceptions when appropriate as well. See the Python documentation for further information on the Built-in Exceptions.