Django raises some of its own exceptions as well as standard Python exceptions.
Django core exception classes are defined in
This exception is raised when attempting to use models before the app loading process, which initializes the ORM, is complete.
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 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
PermissionDenied exception is raised when a user does not have permission to perform the action requested.
MiddlewareNotUsed exception is raised when a middleware is not used in the server configuration.
ImproperlyConfigured exception is raised when Django is somehow improperly configured – for example, if a value in
settings.py is incorrect or unparseable.
FieldError exception is raised when there is a problem with a model field. This can happen for several reasons:
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.
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
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
UnreadablePostError is raised when a user cancels an upload.
Transaction exceptions are defined in
TransactionManagementError is raised for any and all problems related to database transactions.
Exceptions provided by the
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.
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Licensed under the BSD License.