Django raises some of its own exceptions as well as standard Python exceptions.
Django core exception classes are defined in django.core.exceptions.
AppRegistryNotReady¶AppRegistryNotReady¶This exception is raised when attempting to use models before the app loading process, which initializes the ORM, is complete.
ObjectDoesNotExist¶ObjectDoesNotExist¶The base class for Model.DoesNotExist exceptions. A try/except for
ObjectDoesNotExist will catch
DoesNotExist exceptions for all models.
See get().
EmptyResultSet¶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¶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¶MultipleObjectsReturned¶The base class for Model.MultipleObjectsReturned exceptions. A
try/except for MultipleObjectsReturned will catch
MultipleObjectsReturned exceptions for all
models.
See get().
SuspiciousOperation¶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:
DisallowedHostDisallowedModelAdminLookupDisallowedModelAdminToFieldDisallowedRedirectInvalidSessionKeyRequestDataTooBigSuspiciousFileOperationSuspiciousMultipartFormSuspiciousSessionTooManyFieldsSentIf a SuspiciousOperation exception reaches the ASGI/WSGI handler level
it is logged at the Error level and results in
a HttpResponseBadRequest. See the logging
documentation for more information.
PermissionDenied¶PermissionDenied¶The PermissionDenied exception is raised when a user does not have
permission to perform the action requested.
ViewDoesNotExist¶ViewDoesNotExist¶The ViewDoesNotExist exception is raised by
django.urls when a requested view does not exist.
MiddlewareNotUsed¶MiddlewareNotUsed¶The MiddlewareNotUsed exception is raised when a middleware is not
used in the server configuration.
ImproperlyConfigured¶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¶FieldError¶The FieldError exception is raised when there is a problem with a
model field. This can happen for several reasons:
ValidationError¶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.
BadRequest¶BadRequest¶The BadRequest exception is raised when the request cannot be
processed due to a client error. If a BadRequest exception reaches the
ASGI/WSGI handler level it results in a
HttpResponseBadRequest.
RequestAborted¶RequestAborted¶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¶SynchronousOnlyOperation¶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 are defined in django.urls.
Resolver404¶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¶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 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.
Error¶InterfaceError¶DatabaseError¶DataError¶OperationalError¶IntegrityError¶InternalError¶ProgrammingError¶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.
models.ProtectedError¶Raised to prevent deletion of referenced objects when using
django.db.models.PROTECT. models.ProtectedError is a subclass
of IntegrityError.
models.RestrictedError¶Raised to prevent deletion of referenced objects when using
django.db.models.RESTRICT. models.RestrictedError is a subclass
of IntegrityError.
Http exceptions may be imported from django.http.
UnreadablePostError¶UnreadablePostError¶UnreadablePostError is raised when a user cancels an upload.
Sessions exceptions are defined in django.contrib.sessions.exceptions.
SessionInterrupted¶SessionInterrupted¶SessionInterrupted is raised when a session is destroyed in a
concurrent request. It’s a subclass of
BadRequest.
Transaction exceptions are defined in django.db.transaction.
TransactionManagementError¶TransactionManagementError¶TransactionManagementError is raised for any and all problems
related to database transactions.
Exceptions provided by the django.test package.
RedirectCycleError¶client.RedirectCycleError¶RedirectCycleError is raised when the test client detects a
loop or an overly long chain of redirects.
Django raises built-in Python exceptions when appropriate as well. See the Python documentation for further information on the Built-in Exceptions.
Jul 27, 2022