tower/util/
map_request.rs

1use std::fmt;
2use std::task::{Context, Poll};
3use tower_layer::Layer;
4use tower_service::Service;
5
6/// Service returned by the [`MapRequest`] combinator.
7///
8/// [`MapRequest`]: crate::util::ServiceExt::map_request
9#[derive(Clone)]
10pub struct MapRequest<S, F> {
11    inner: S,
12    f: F,
13}
14
15impl<S, F> fmt::Debug for MapRequest<S, F>
16where
17    S: fmt::Debug,
18{
19    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
20        f.debug_struct("MapRequest")
21            .field("inner", &self.inner)
22            .field("f", &format_args!("{}", std::any::type_name::<F>()))
23            .finish()
24    }
25}
26
27impl<S, F> MapRequest<S, F> {
28    /// Creates a new [`MapRequest`] service.
29    pub const fn new(inner: S, f: F) -> Self {
30        MapRequest { inner, f }
31    }
32
33    /// Returns a new [`Layer`] that produces [`MapRequest`] services.
34    ///
35    /// This is a convenience function that simply calls [`MapRequestLayer::new`].
36    ///
37    /// [`Layer`]: tower_layer::Layer
38    pub fn layer(f: F) -> MapRequestLayer<F> {
39        MapRequestLayer { f }
40    }
41}
42
43impl<S, F, R1, R2> Service<R1> for MapRequest<S, F>
44where
45    S: Service<R2>,
46    F: FnMut(R1) -> R2,
47{
48    type Response = S::Response;
49    type Error = S::Error;
50    type Future = S::Future;
51
52    #[inline]
53    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> {
54        self.inner.poll_ready(cx)
55    }
56
57    #[inline]
58    fn call(&mut self, request: R1) -> S::Future {
59        self.inner.call((self.f)(request))
60    }
61}
62
63/// A [`Layer`] that produces [`MapRequest`] services.
64///
65/// [`Layer`]: tower_layer::Layer
66#[derive(Clone, Debug)]
67pub struct MapRequestLayer<F> {
68    f: F,
69}
70
71impl<F> MapRequestLayer<F> {
72    /// Creates a new [`MapRequestLayer`].
73    pub const fn new(f: F) -> Self {
74        MapRequestLayer { f }
75    }
76}
77
78impl<S, F> Layer<S> for MapRequestLayer<F>
79where
80    F: Clone,
81{
82    type Service = MapRequest<S, F>;
83
84    fn layer(&self, inner: S) -> Self::Service {
85        MapRequest {
86            f: self.f.clone(),
87            inner,
88        }
89    }
90}
tower/util/map_request.rs

tower/util/
map_request.rs
