hyper/service/
make.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
use std::error::Error as StdError;
use std::fmt;
use std::future::Future;
use std::task::{Context, Poll};

use tokio::io::{AsyncRead, AsyncWrite};

use super::{HttpService, Service};
use crate::body::HttpBody;

// The same "trait alias" as tower::MakeConnection, but inlined to reduce
// dependencies.
pub trait MakeConnection<Target>: self::sealed::Sealed<(Target,)> {
    type Connection: AsyncRead + AsyncWrite;
    type Error;
    type Future: Future<Output = Result<Self::Connection, Self::Error>>;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>;
    fn make_connection(&mut self, target: Target) -> Self::Future;
}

impl<S, Target> self::sealed::Sealed<(Target,)> for S where S: Service<Target> {}

impl<S, Target> MakeConnection<Target> for S
where
    S: Service<Target>,
    S::Response: AsyncRead + AsyncWrite,
{
    type Connection = S::Response;
    type Error = S::Error;
    type Future = S::Future;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Service::poll_ready(self, cx)
    }

    fn make_connection(&mut self, target: Target) -> Self::Future {
        Service::call(self, target)
    }
}

// Just a sort-of "trait alias" of `MakeService`, not to be implemented
// by anyone, only used as bounds.
pub trait MakeServiceRef<Target, ReqBody>: self::sealed::Sealed<(Target, ReqBody)> {
    type ResBody: HttpBody;
    type Error: Into<Box<dyn StdError + Send + Sync>>;
    type Service: HttpService<ReqBody, ResBody = Self::ResBody, Error = Self::Error>;
    type MakeError: Into<Box<dyn StdError + Send + Sync>>;
    type Future: Future<Output = Result<Self::Service, Self::MakeError>>;

    // Acting like a #[non_exhaustive] for associated types of this trait.
    //
    // Basically, no one outside of hyper should be able to set this type
    // or declare bounds on it, so it should prevent people from creating
    // trait objects or otherwise writing code that requires using *all*
    // of the associated types.
    //
    // Why? So we can add new associated types to this alias in the future,
    // if necessary.
    type __DontNameMe: self::sealed::CantImpl;

    fn poll_ready_ref(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::MakeError>>;

    fn make_service_ref(&mut self, target: &Target) -> Self::Future;
}

impl<T, Target, E, ME, S, F, IB, OB> MakeServiceRef<Target, IB> for T
where
    T: for<'a> Service<&'a Target, Error = ME, Response = S, Future = F>,
    E: Into<Box<dyn StdError + Send + Sync>>,
    ME: Into<Box<dyn StdError + Send + Sync>>,
    S: HttpService<IB, ResBody = OB, Error = E>,
    F: Future<Output = Result<S, ME>>,
    IB: HttpBody,
    OB: HttpBody,
{
    type Error = E;
    type Service = S;
    type ResBody = OB;
    type MakeError = ME;
    type Future = F;

    type __DontNameMe = self::sealed::CantName;

    fn poll_ready_ref(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::MakeError>> {
        self.poll_ready(cx)
    }

    fn make_service_ref(&mut self, target: &Target) -> Self::Future {
        self.call(target)
    }
}

impl<T, Target, S, B1, B2> self::sealed::Sealed<(Target, B1)> for T
where
    T: for<'a> Service<&'a Target, Response = S>,
    S: HttpService<B1, ResBody = B2>,
    B1: HttpBody,
    B2: HttpBody,
{
}

/// Create a `MakeService` from a function.
///
/// # Example
///
/// ```
/// # #[cfg(feature = "runtime")]
/// # async fn run() {
/// use std::convert::Infallible;
/// use hyper::{Body, Request, Response, Server};
/// use hyper::server::conn::AddrStream;
/// use hyper::service::{make_service_fn, service_fn};
///
/// let addr = ([127, 0, 0, 1], 3000).into();
///
/// let make_svc = make_service_fn(|socket: &AddrStream| {
///     let remote_addr = socket.remote_addr();
///     async move {
///         Ok::<_, Infallible>(service_fn(move |_: Request<Body>| async move {
///             Ok::<_, Infallible>(
///                 Response::new(Body::from(format!("Hello, {}!", remote_addr)))
///             )
///         }))
///     }
/// });
///
/// // Then bind and serve...
/// let server = Server::bind(&addr)
///     .serve(make_svc);
///
/// // Finally, spawn `server` onto an Executor...
/// if let Err(e) = server.await {
///     eprintln!("server error: {}", e);
/// }
/// # }
/// # fn main() {}
/// ```
pub fn make_service_fn<F, Target, Ret>(f: F) -> MakeServiceFn<F>
where
    F: FnMut(&Target) -> Ret,
    Ret: Future,
{
    MakeServiceFn { f }
}

/// `MakeService` returned from [`make_service_fn`]
#[derive(Clone, Copy)]
pub struct MakeServiceFn<F> {
    f: F,
}

impl<'t, F, Ret, Target, Svc, MkErr> Service<&'t Target> for MakeServiceFn<F>
where
    F: FnMut(&Target) -> Ret,
    Ret: Future<Output = Result<Svc, MkErr>>,
    MkErr: Into<Box<dyn StdError + Send + Sync>>,
{
    type Error = MkErr;
    type Response = Svc;
    type Future = Ret;

    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Poll::Ready(Ok(()))
    }

    fn call(&mut self, target: &'t Target) -> Self::Future {
        (self.f)(target)
    }
}

impl<F> fmt::Debug for MakeServiceFn<F> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("MakeServiceFn").finish()
    }
}

mod sealed {
    pub trait Sealed<X> {}

    #[allow(unreachable_pub)] // This is intentional.
    pub trait CantImpl {}

    #[allow(missing_debug_implementations)]
    pub enum CantName {}

    impl CantImpl for CantName {}
}