Struct MiddlewareStack 

pub struct MiddlewareStack { /* private fields */ }

A stack of middleware that wraps a handler.

The stack executes middleware in order:

1. before hooks run first-to-last (registration order)
2. Handler executes (if no middleware short-circuited)
3. after hooks run last-to-first (reverse order)

Example

let mut stack = MiddlewareStack::new();
stack.push(LoggingMiddleware);
stack.push(AuthMiddleware);
stack.push(CorsMiddleware);

let response = stack.execute(&handler, &ctx, &mut request).await;

Implementations

impl MiddlewareStack

pub fn new() -> Self

Creates an empty middleware stack.

pub fn with_capacity(capacity: usize) -> Self

Creates a middleware stack with pre-allocated capacity.

pub fn push<M: Middleware + 'static>(&mut self, middleware: M)

Adds middleware to the end of the stack.

Middleware added first will have its before run first and after run last.

pub fn push_arc(&mut self, middleware: Arc<dyn Middleware>)

Adds middleware wrapped in an Arc.

Useful for sharing middleware across multiple stacks.

pub fn len(&self) -> usize

Returns the number of middleware in the stack.

pub fn is_empty(&self) -> bool

Returns true if the stack is empty.

pub async fn execute<H: Handler>( &self, handler: &H, ctx: &RequestContext, req: &mut Request, ) -> Response

Executes the middleware stack with the given handler.

Execution Order

1. Each middleware’s before hook runs in order
2. If any before returns Break, skip remaining middleware and handler
3. Handler executes
4. Each middleware’s after hook runs in reverse order

Short-Circuit Behavior

If middleware N calls Break(response):

• Middleware N+1..end before hooks do NOT run
• Handler does NOT run
• Middleware 0..N after hooks STILL run (in reverse: N, N-1, …, 0)

This ensures cleanup middleware (like timing or logging) always runs.

Trait Implementations

impl Default for MiddlewareStack

fn default() -> MiddlewareStack

Returns the “default value” for a type.