Exception Filters
Catch and format errors raised during a request, in TypeScript and Python
Exception filters run last in the request pipeline. They catch anything thrown by guards, middleware, interceptors, pipes, or your handler, and turn it into a consistent error response.
Write and apply a filter
Mark the class, implement catch(), and attach it to a handler.
Mark a class with @ExceptionFilter() and implement catch:
import { ExceptionFilter, ExceptionFilterInterface } from '@nitrostack/core';
@ExceptionFilter()
export class HttpExceptionFilter implements ExceptionFilterInterface {
catch(exception: unknown, context: ExecutionContext): any {
// Implementation
}
}Apply it with @UseFilters:
@Tool({ name: 'risky_operation' })
@UseFilters(GlobalExceptionFilter)
async riskyOperation(input: RiskyInput, ctx: ExecutionContext) {
// Errors caught and formatted by filter
}Protocol: async def catch(self, error: Exception, context: ExecutionContext) -> Any.
from nitrostack import use_filters, injectable, ExecutionContext
@injectable()
class HttpExceptionFilter:
async def catch(self, error: Exception, context: ExecutionContext):
context.logger.error(f"{type(error).__name__}: {error}")
return {
"error": type(error).__name__,
"message": str(error),
"tool": context.tool_name,
}
@use_filters(HttpExceptionFilter)
async def handler(...):
...Scaffold: nitrostack-py generate filter HttpException.