Django Exceptions — Django documentation
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
- This exception is raised when attempting to use models before the app loading process, which initializes the ORM, is complete.
ObjectDoesNotExist
- exception ObjectDoesNotExist
The base class for Model.DoesNotExist exceptions. A
try/except
forObjectDoesNotExist
will catch DoesNotExist exceptions for all models.See get().
EmptyResultSet
- exception EmptyResultSet
EmptyResultSet
may be raised during query generation if a query won’t return any results. Most Django projects won’t encounter this exception, but it might be useful for implementing custom lookups and expressions.
FieldDoesNotExist
- exception FieldDoesNotExist
- The
FieldDoesNotExist
exception is raised by a model’s_meta.get_field()
method when the requested field does not exist on the model or on the model’s parents.
MultipleObjectsReturned
- exception MultipleObjectsReturned
The base class for Model.MultipleObjectsReturned exceptions. A
try/except
forMultipleObjectsReturned
will catch MultipleObjectsReturned exceptions for all models.See get().
SuspiciousOperation
- exception SuspiciousOperation
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 of
SuspiciousOperation
include:DisallowedHost
DisallowedModelAdminLookup
DisallowedModelAdminToField
DisallowedRedirect
InvalidSessionKey
RequestDataTooBig
SuspiciousFileOperation
SuspiciousMultipartForm
SuspiciousSession
TooManyFieldsSent
If a
SuspiciousOperation
exception reaches the ASGI/WSGI handler level it is logged at theError
level and results in a HttpResponseBadRequest. See the logging documentation for more information.
PermissionDenied
- exception PermissionDenied
- The PermissionDenied exception is raised when a user does not have permission to perform the action requested.
ViewDoesNotExist
- exception ViewDoesNotExist
- The ViewDoesNotExist exception is raised by django.urls when a requested view does not exist.
MiddlewareNotUsed
- exception MiddlewareNotUsed
- The MiddlewareNotUsed exception is raised when a middleware is not used in the server configuration.
ImproperlyConfigured
- exception ImproperlyConfigured
- The ImproperlyConfigured exception is raised when Django is somehow improperly configured – for example, if a value in
settings.py
is incorrect or unparseable.
FieldError
- exception FieldError
- 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
- 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.
NON_FIELD_ERRORS
- NON_FIELD_ERRORS
ValidationError
s that don’t belong to a particular field in a form or model are classified as NON_FIELD_ERRORS
. This constant is used as a key in dictionaries that otherwise map fields to their respective list of errors.
RequestAborted
- exception RequestAborted
New in version 3.0.
The RequestAborted exception is raised when a HTTP body being read in by the handler is cut off midstream and the client connection closes, or when the client does not send data and hits a timeout where the server closes the connection.
It is internal to the HTTP handler modules and you are unlikely to see it elsewhere. If you are modifying HTTP handling code, you should raise this when you encounter an aborted request to make sure the socket is closed cleanly.
SynchronousOnlyOperation
- exception SynchronousOnlyOperation
New in version 3.0.
The SynchronousOnlyOperation exception is raised when code that is only allowed in synchronous Python code is called from an asynchronous context (a thread with a running asynchronous event loop). These parts of Django are generally heavily reliant on thread-safety to function and don’t work correctly under coroutines sharing the same thread.
If you are trying to call code that is synchronous-only from an asynchronous thread, then create a synchronous thread and call it in that. You can accomplish this is with asgiref.sync.sync_to_async().
URL Resolver exceptions
URL Resolver exceptions are defined in django.urls
.
Resolver404
- exception Resolver404
- The Resolver404 exception is raised by resolve() if the path passed to
resolve()
doesn’t map to a view. It’s a subclass of django.http.Http404.
NoReverseMatch
- exception NoReverseMatch
- The NoReverseMatch exception is raised by django.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.
- exception Error
- exception InterfaceError
- exception DatabaseError
- exception DataError
- exception OperationalError
- exception IntegrityError
- exception InternalError
- exception ProgrammingError
- exception NotSupportedError
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.
- exception models.ProtectedError
Raised to prevent deletion of referenced objects when using django.db.models.PROTECT. models.ProtectedError is a subclass of IntegrityError.
- exception models.RestrictedError
Raised to prevent deletion of referenced objects when using django.db.models.RESTRICT. models.RestrictedError is a subclass of IntegrityError.
Http Exceptions
Http exceptions may be imported from django.http
.
UnreadablePostError
- exception UnreadablePostError
- UnreadablePostError is raised when a user cancels an upload.
Transaction Exceptions
Transaction exceptions are defined in django.db.transaction
.
TransactionManagementError
- exception TransactionManagementError
- 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 bltin-exceptions.