rama_core/layer/
map_state.rs

1use crate::{Context, Layer, Service};
2use rama_utils::macros::define_inner_service_accessors;
3
4/// Middleware that can be used to map the state,
5/// and pass it as the new state for the inner service.
6pub struct MapState<S, F> {
7    inner: S,
8    f: F,
9}
10
11impl<S: std::fmt::Debug, F> std::fmt::Debug for MapState<S, F> {
12    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
13        f.debug_struct("MapState")
14            .field("inner", &self.inner)
15            .field("f", &format_args!("{}", std::any::type_name::<F>()))
16            .finish()
17    }
18}
19
20impl<S, F> Clone for MapState<S, F>
21where
22    S: Clone,
23    F: Clone,
24{
25    fn clone(&self) -> Self {
26        Self {
27            inner: self.inner.clone(),
28            f: self.f.clone(),
29        }
30    }
31}
32
33impl<S, F> MapState<S, F> {
34    /// Create a new `MapState` with the given constructor.
35    pub const fn new(inner: S, f: F) -> Self {
36        Self { inner, f }
37    }
38
39    define_inner_service_accessors!();
40}
41
42impl<S, F, W, State, Request> Service<State, Request> for MapState<S, F>
43where
44    S: Service<W, Request>,
45    State: Clone + Send + Sync + 'static,
46    W: Send + Sync + 'static,
47    F: FnOnce(State) -> W + Clone + Send + Sync + 'static,
48    Request: Send + 'static,
49{
50    type Response = S::Response;
51    type Error = S::Error;
52
53    #[inline]
54    fn serve(
55        &self,
56        ctx: Context<State>,
57        req: Request,
58    ) -> impl Future<Output = Result<Self::Response, Self::Error>> + Send + '_ {
59        let ctx = ctx.map_state(self.f.clone());
60        self.inner.serve(ctx, req)
61    }
62}
63
64/// Middleware that can be used to map the state,
65/// and pass it as the new state for the inner service.
66pub struct MapStateLayer<F> {
67    f: F,
68}
69
70impl<F> std::fmt::Debug for MapStateLayer<F> {
71    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
72        f.debug_struct("MapStateLayer")
73            .field("f", &format_args!("{}", std::any::type_name::<F>()))
74            .finish()
75    }
76}
77
78impl<F: Clone> Clone for MapStateLayer<F> {
79    fn clone(&self) -> Self {
80        Self { f: self.f.clone() }
81    }
82}
83
84impl<F> MapStateLayer<F> {
85    /// Create a new [`MapStateLayer`] with the given constructor.
86    pub const fn new(f: F) -> Self {
87        Self { f }
88    }
89}
90
91impl<S, F: Clone> Layer<S> for MapStateLayer<F> {
92    type Service = MapState<S, F>;
93
94    fn layer(&self, inner: S) -> Self::Service {
95        MapState::new(inner, self.f.clone())
96    }
97
98    fn into_layer(self, inner: S) -> Self::Service {
99        MapState::new(inner, self.f)
100    }
101}
rama_core/layer/map_state.rs

rama_core/layer/
map_state.rs
