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use crate::blueprint::conversions::raw_identifiers2callable;
use crate::blueprint::reflection::RawIdentifiers;
use pavex_bp_schema::{Blueprint as BlueprintSchema, Component, PostProcessingMiddleware};
/// The type returned by [`Blueprint::post_process`].
///
/// It allows you to further configure the behaviour of post-processing middleware
/// you just registered.
///
/// [`Blueprint::post_process`]: crate::blueprint::Blueprint::post_process
pub struct RegisteredPostProcessingMiddleware<'a> {
pub(crate) blueprint: &'a mut BlueprintSchema,
/// The index of the registered middleware in the blueprint's `components` vector.
pub(crate) component_id: usize,
}
impl<'a> RegisteredPostProcessingMiddleware<'a> {
#[track_caller]
/// Register an error handler.
///
/// If an error handler has already been registered for this middleware, it will be
/// overwritten.
///
/// # Guide
///
/// Check out the ["Error handlers"](https://pavex.dev/docs/guide/errors/error_handlers)
/// section of Pavex's guide for a thorough introduction to error handlers
/// in Pavex applications.
///
/// # Example
///
/// ```rust
/// use pavex::{f, blueprint::Blueprint};
/// use pavex::response::Response;
/// # struct SizeError;
///
/// // 👇 a fallible post-processing middleware
/// fn max_response_size(response: Response) -> Result<Response, SizeError>
/// {
/// // [...]
/// # todo!()
/// }
///
/// fn error_to_response(error: &SizeError) -> Response {
/// // [...]
/// # todo!()
/// }
///
/// # fn main() {
/// let mut bp = Blueprint::new();
/// bp.post_process(f!(crate::max_response_size))
/// .error_handler(f!(crate::error_to_response));
/// # }
/// ```
pub fn error_handler(mut self, error_handler: RawIdentifiers) -> Self {
let callable = raw_identifiers2callable(error_handler);
self.post_processing_middleware().error_handler = Some(callable);
self
}
fn post_processing_middleware(&mut self) -> &mut PostProcessingMiddleware {
let component = &mut self.blueprint.components[self.component_id];
let Component::PostProcessingMiddleware(c) = component else {
unreachable!("The component should be a post-processing middleware")
};
c
}
}