Django raises some of its own exceptions as well as standard Python exceptions.
Django core exception classes are defined in
EmptyResultSetmay 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.
FieldDoesNotExistexception 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.
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
PermissionDeniedexception is raised when a user does not have permission to perform the action requested.
ViewDoesNotExistexception is raised by
django.urlswhen a requested view does not exist.
MiddlewareNotUsedexception is raised when a middleware is not used in the server configuration.
ImproperlyConfiguredexception is raised when Django is somehow improperly configured -- for example, if a value in
settings.pyis incorrect or unparseable.
FieldErrorexception is raised when there is a problem with a model field. This can happen for several reasons:
ValidationErrorexception 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.
ValidationErrors 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 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 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
URL Resolver exceptions are defined in
Resolver404exception is raised by
resolve()if the path passed to
resolve()doesn't map to a view. It's a subclass of
Database exceptions may be imported from
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
Http exceptions may be imported from
UnreadablePostErroris raised when a user cancels an upload.
Transaction exceptions are defined in
TransactionManagementErroris raised for any and all problems related to database transactions.
Exceptions provided by the
RedirectCycleErroris 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 bltin-exceptions.