Exceptions

Application exception classes and error handling.

Module Contents

Site-wide exception handlers with HTMX-aware flash message support.

not_found_exception_handler(request, exc)

Handle 404 Not Found exceptions site-wide.

For API requests: Returns JSON error response. For HTMX requests: Returns empty response with HX-Trigger for toast notification. For regular requests: Renders the 404 error template with 5-minute cache.

Parameters:

• request (Request) – The incoming request

• exc (NotFoundException) – The NotFoundException that was raised

Return type:

Response | Template

Returns:

JSON response, HTMX toast response, or rendered error template

http_exception_handler(request, exc)

Handle generic HTTP exceptions site-wide.

For API requests: Returns JSON error response. For HTMX requests: Returns toast notification. For browser requests: Returns HTML template or redirect.

Parameters:

• request (Request) – The incoming request

• exc (HTTPException) – The HTTPException that was raised

Return type:

Response | Template | Redirect

Returns:

Appropriate response based on request type and exception

permission_denied_handler(request, exc)

Handle permission denied exceptions.

For API requests: Returns JSON error response. For HTMX requests: Returns toast notification. For browser requests: Returns 403 template.

Parameters:

• request (Request) – The incoming request

• exc (PermissionDeniedException) – The PermissionDeniedException that was raised

Return type:

Response | Template

Returns:

JSON response, HTMX toast response, or rendered 403 template

internal_server_error_handler(request, exc)

Handle internal server errors.

For API requests: Returns JSON error response. For HTMX requests: Returns toast notification. For browser requests: Returns 500 template.

Parameters:

• request (Request) – The incoming request

• exc (InternalServerException) – The InternalServerException that was raised

Return type:

Response | Template

Returns:

JSON response, HTMX toast response, or rendered 500 template

get_exception_handlers()

Get all site-wide exception handlers.

Return type:

dict

Returns:

Dictionary mapping exception types to their handlers

Exception Hierarchy

The exception hierarchy provides structured error handling:

• ApplicationError - Base exception for all application errors

• AuthenticationError - Authentication failures

• AuthorizationError - Authorization/permission failures

• NotFoundError - Resource not found errors

• ValidationError - Input validation errors

• ConflictError - Resource conflict errors