hreq 0.8.0

hreq is a user first async http client
Documentation 
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

use std::fmt;
use std::future::Future;
use std::sync::Arc;

use hreq_h1::mpsc::{Receiver, Sender};

/// Handle to a running server.
///
/// The server functions as long as this handle is not dropped.
pub struct ServerHandle {
    tx_shutdown: Sender<()>,
    rx_confirm: Receiver<()>,
}

impl ServerHandle {
    pub(crate) async fn new() -> (Self, EndFut) {
        let (tx_shutdown, rx_shutdown) = Receiver::new(1);
        let (tx_confirm, rx_confirm) = Receiver::new(1);

        (
            ServerHandle {
                tx_shutdown,
                rx_confirm,
            },
            EndFut {
                rx_shutdown,
                tx_confirm: Arc::new(tx_confirm),
            },
        )
    }

    /// Signal to the server to close down. Stop listening to the port and exit.
    pub async fn shutdown(self) {
        // When we drop the tx_shutdown sender, all connected
        // receivers are woken up and realise it's gone.
        let ServerHandle {
            tx_shutdown,
            rx_confirm,
        } = self;

        drop(tx_shutdown);

        trace!("Await server shutdown confirmation");
        rx_confirm.recv().await;
    }

    /// Await this to keep the server alive forever. Will never return.
    pub async fn keep_alive(self) -> ! {
        NoFuture.await;
        unreachable!()
    }
}

#[derive(Clone)]
pub(crate) struct EndFut {
    rx_shutdown: Receiver<()>,
    tx_confirm: Arc<Sender<()>>,
}

impl EndFut {
    pub async fn race<F>(&self, f: F) -> Option<F::Output>
    where
        F: Future,
    {
        // first to complete...

        let wait_for_value = Box::pin(async {
            let v = f.await;
            Some(v)
        });

        let wait_for_end = Box::pin(async {
            self.rx_shutdown.recv().await;
            None
        });

        let ret = Select(Some(Inner(wait_for_value, wait_for_end))).await;

        trace!("Race is ended: {}", ret.is_none());

        ret
    }
}

impl Drop for EndFut {
    fn drop(&mut self) {
        let count = Arc::strong_count(&self.tx_confirm);
        trace!("EndFut instances left: {}", count - 1);
    }
}

struct NoFuture;

impl std::future::Future for NoFuture {
    type Output = ();
    fn poll(
        self: std::pin::Pin<&mut Self>,
        _cx: &mut std::task::Context,
    ) -> std::task::Poll<Self::Output> {
        std::task::Poll::Pending
    }
}

impl fmt::Debug for ServerHandle {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "ServerHandle")
    }
}

use std::pin::Pin;
use std::task::{Context, Poll};

struct Select<A, B>(Option<Inner<A, B>>);

struct Inner<A, B>(A, B);

impl<A, B, T> Future for Select<A, B>
where
    A: Future<Output = T> + Unpin,
    B: Future<Output = T> + Unpin,
{
    type Output = T;

    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
        let this = self.get_mut();

        if let Some(inner) = &mut this.0 {
            let ret = match Pin::new(&mut inner.0).poll(cx) {
                Poll::Ready(v) => Poll::Ready(v),
                Poll::Pending => Pin::new(&mut inner.1).poll(cx),
            };

            if ret.is_ready() {
                this.0 = None;
            }

            ret
        } else {
            warn!("Poll::Pending on finished Select");

            Poll::Pending
        }
    }
}