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
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219

//! Middleware that applies a timeout to request and response bodies.
//!
//! Bodies must produce data at most within the specified timeout.
//! If the body does not produce a requested data frame within the timeout period, it will return an error.
//!
//! # Differences from [`crate::timeout::Timeout`]
//!
//! [`crate::timeout::Timeout`] applies a timeout to the request future, not body.
//! That timeout is not reset when bytes are handled, whether the request is active or not.
//! Bodies are handled asynchronously outside of the tower stack's future and thus needs an additional timeout.
//!
//! This middleware will return a [`TimeoutError`].
//!
//! # Example
//!
//! ```
//! use http::{Request, Response};
//! use hyper::Body;
//! use std::time::Duration;
//! use tower::ServiceBuilder;
//! use tower_http::timeout::RequestBodyTimeoutLayer;
//!
//! async fn handle(_: Request<Body>) -> Result<Response<Body>, std::convert::Infallible> {
//!     // ...
//!     # todo!()
//! }
//!
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! let svc = ServiceBuilder::new()
//!     // Timeout bodies after 30 seconds of inactivity
//!     .layer(RequestBodyTimeoutLayer::new(Duration::from_secs(30)))
//!     .service_fn(handle);
//! # Ok(())
//! # }
//! ```

use crate::BoxError;
use futures_core::{ready, Future};
use http_body::Body;
use pin_project_lite::pin_project;
use std::{
    pin::Pin,
    task::{Context, Poll},
    time::Duration,
};
use tokio::time::{sleep, Sleep};

pin_project! {
    /// Wrapper around a [`http_body::Body`] to time out if data is not ready within the specified duration.
    pub struct TimeoutBody<B> {
        timeout: Duration,
        // In http-body 1.0, `poll_*` will be merged into `poll_frame`.
        // Merge the two `sleep_data` and `sleep_trailers` into one `sleep`.
        // See: https://github.com/tower-rs/tower-http/pull/303#discussion_r1004834958
        #[pin]
        sleep_data: Option<Sleep>,
        #[pin]
        sleep_trailers: Option<Sleep>,
        #[pin]
        body: B,
    }
}

impl<B> TimeoutBody<B> {
    /// Creates a new [`TimeoutBody`].
    pub fn new(timeout: Duration, body: B) -> Self {
        TimeoutBody {
            timeout,
            sleep_data: None,
            sleep_trailers: None,
            body,
        }
    }
}

impl<B> Body for TimeoutBody<B>
where
    B: Body,
    B::Error: Into<BoxError>,
{
    type Data = B::Data;
    type Error = Box<dyn std::error::Error + Send + Sync>;

    fn poll_data(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Option<Result<Self::Data, Self::Error>>> {
        let mut this = self.project();

        // Start the `Sleep` if not active.
        let sleep_pinned = if let Some(some) = this.sleep_data.as_mut().as_pin_mut() {
            some
        } else {
            this.sleep_data.set(Some(sleep(*this.timeout)));
            this.sleep_data.as_mut().as_pin_mut().unwrap()
        };

        // Error if the timeout has expired.
        if let Poll::Ready(()) = sleep_pinned.poll(cx) {
            return Poll::Ready(Some(Err(Box::new(TimeoutError(())))));
        }

        // Check for body data.
        let data = ready!(this.body.poll_data(cx));
        // Some data is ready. Reset the `Sleep`...
        this.sleep_data.set(None);

        Poll::Ready(data.transpose().map_err(Into::into).transpose())
    }

    fn poll_trailers(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Result<Option<http::HeaderMap>, Self::Error>> {
        let mut this = self.project();

        // In http-body 1.0, `poll_*` will be merged into `poll_frame`.
        // Merge the two `sleep_data` and `sleep_trailers` into one `sleep`.
        // See: https://github.com/tower-rs/tower-http/pull/303#discussion_r1004834958

        let sleep_pinned = if let Some(some) = this.sleep_trailers.as_mut().as_pin_mut() {
            some
        } else {
            this.sleep_trailers.set(Some(sleep(*this.timeout)));
            this.sleep_trailers.as_mut().as_pin_mut().unwrap()
        };

        // Error if the timeout has expired.
        if let Poll::Ready(()) = sleep_pinned.poll(cx) {
            return Poll::Ready(Err(Box::new(TimeoutError(()))));
        }

        this.body.poll_trailers(cx).map_err(Into::into)
    }
}

/// Error for [`TimeoutBody`].
#[derive(Debug)]
pub struct TimeoutError(());

impl std::error::Error for TimeoutError {}

impl std::fmt::Display for TimeoutError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "data was not received within the designated timeout")
    }
}
#[cfg(test)]
mod tests {
    use super::*;

    use bytes::Bytes;
    use pin_project_lite::pin_project;
    use std::{error::Error, fmt::Display};

    #[derive(Debug)]
    struct MockError;

    impl Error for MockError {}
    impl Display for MockError {
        fn fmt(&self, _f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
            todo!()
        }
    }

    pin_project! {
        struct MockBody {
            #[pin]
            sleep: Sleep
        }
    }

    impl Body for MockBody {
        type Data = Bytes;
        type Error = MockError;

        fn poll_data(
            self: Pin<&mut Self>,
            cx: &mut Context<'_>,
        ) -> Poll<Option<Result<Self::Data, Self::Error>>> {
            let this = self.project();
            this.sleep.poll(cx).map(|_| Some(Ok(vec![].into())))
        }

        fn poll_trailers(
            self: Pin<&mut Self>,
            _cx: &mut Context<'_>,
        ) -> Poll<Result<Option<http::HeaderMap>, Self::Error>> {
            todo!()
        }
    }

    #[tokio::test]
    async fn test_body_available_within_timeout() {
        let mock_sleep = Duration::from_secs(1);
        let timeout_sleep = Duration::from_secs(2);

        let mock_body = MockBody {
            sleep: sleep(mock_sleep),
        };
        let timeout_body = TimeoutBody::new(timeout_sleep, mock_body);

        assert!(timeout_body.boxed().data().await.unwrap().is_ok());
    }

    #[tokio::test]
    async fn test_body_unavailable_within_timeout_error() {
        let mock_sleep = Duration::from_secs(2);
        let timeout_sleep = Duration::from_secs(1);

        let mock_body = MockBody {
            sleep: sleep(mock_sleep),
        };
        let timeout_body = TimeoutBody::new(timeout_sleep, mock_body);

        assert!(timeout_body.boxed().data().await.unwrap().is_err());
    }
}