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.
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
settings.pyis incorrect or unparseable.
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.
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.
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
resolve()doesn’t map to a view. It’s a subclass of django.http.Http404.
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 information provided.
Http exceptions may be imported from
Transaction exceptions are defined in
Exceptions provided by the
Django raises built-in Python exceptions when appropriate as well. See the Python documentation for further information on the Built-in Exceptions.