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| 1 | +use std::{ops::Deref, sync::Arc}; |
| 2 | + |
| 3 | +use http::Request; |
| 4 | +use tokio::sync::watch; |
| 5 | + |
| 6 | +use super::Connected; |
| 7 | + |
| 8 | +/// [`CaptureConnection`] allows callers to capture [`Connected`] information |
| 9 | +/// |
| 10 | +/// To capture a connection for a request, use [`capture_connection`]. |
| 11 | +#[derive(Debug, Clone)] |
| 12 | +pub struct CaptureConnection { |
| 13 | + rx: watch::Receiver<Option<Connected>>, |
| 14 | +} |
| 15 | + |
| 16 | +/// Capture the connection for a given request |
| 17 | +/// |
| 18 | +/// When making a request with Hyper, the underlying connection must implement the [`Connection`] trait. |
| 19 | +/// [`capture_connection`] allows a caller to capture the returned [`Connected`] structure as soon |
| 20 | +/// as the connection is established. |
| 21 | +/// |
| 22 | +/// *Note*: If establishing a connection fails, [`CaptureConnection::connection_metadata`] will always return none. |
| 23 | +/// |
| 24 | +/// # Examples |
| 25 | +/// |
| 26 | +/// **Synchronous access**: |
| 27 | +/// The [`CaptureConnection::connection_metadata`] method allows callers to check if a connection has been |
| 28 | +/// established. This is ideal for situations where you are certain the connection has already |
| 29 | +/// been established (e.g. after the response future has already completed). |
| 30 | +/// ```rust |
| 31 | +/// use hyper_util::client::legacy::connect::capture_connection; |
| 32 | +/// let mut request = http::Request::builder() |
| 33 | +/// .uri("http://foo.com") |
| 34 | +/// .body(()) |
| 35 | +/// .unwrap(); |
| 36 | +/// |
| 37 | +/// let captured_connection = capture_connection(&mut request); |
| 38 | +/// // some time later after the request has been sent... |
| 39 | +/// let connection_info = captured_connection.connection_metadata(); |
| 40 | +/// println!("we are connected! {:?}", connection_info.as_ref()); |
| 41 | +/// ``` |
| 42 | +/// |
| 43 | +/// **Asynchronous access**: |
| 44 | +/// The [`CaptureConnection::wait_for_connection_metadata`] method returns a future resolves as soon as the |
| 45 | +/// connection is available. |
| 46 | +/// |
| 47 | +/// ```rust |
| 48 | +/// # #[cfg(feature = "tokio")] |
| 49 | +/// # async fn example() { |
| 50 | +/// use hyper_util::client::legacy::connect::capture_connection; |
| 51 | +/// use hyper_util::client::legacy::Client; |
| 52 | +/// use hyper_util::rt::TokioExecutor; |
| 53 | +/// use bytes::Bytes; |
| 54 | +/// use http_body_util::Empty; |
| 55 | +/// let mut request = http::Request::builder() |
| 56 | +/// .uri("http://foo.com") |
| 57 | +/// .body(Empty::<Bytes>::new()) |
| 58 | +/// .unwrap(); |
| 59 | +/// |
| 60 | +/// let mut captured = capture_connection(&mut request); |
| 61 | +/// tokio::task::spawn(async move { |
| 62 | +/// let connection_info = captured.wait_for_connection_metadata().await; |
| 63 | +/// println!("we are connected! {:?}", connection_info.as_ref()); |
| 64 | +/// }); |
| 65 | +/// |
| 66 | +/// let client = Client::builder(TokioExecutor::new()).build_http(); |
| 67 | +/// client.request(request).await.expect("request failed"); |
| 68 | +/// # } |
| 69 | +/// ``` |
| 70 | +pub fn capture_connection<B>(request: &mut Request<B>) -> CaptureConnection { |
| 71 | + let (tx, rx) = CaptureConnection::new(); |
| 72 | + request.extensions_mut().insert(tx); |
| 73 | + rx |
| 74 | +} |
| 75 | + |
| 76 | +/// TxSide for [`CaptureConnection`] |
| 77 | +/// |
| 78 | +/// This is inserted into `Extensions` to allow Hyper to back channel connection info |
| 79 | +#[derive(Clone)] |
| 80 | +pub(crate) struct CaptureConnectionExtension { |
| 81 | + tx: Arc<watch::Sender<Option<Connected>>>, |
| 82 | +} |
| 83 | + |
| 84 | +impl CaptureConnectionExtension { |
| 85 | + pub(crate) fn set(&self, connected: &Connected) { |
| 86 | + self.tx.send_replace(Some(connected.clone())); |
| 87 | + } |
| 88 | +} |
| 89 | + |
| 90 | +impl CaptureConnection { |
| 91 | + /// Internal API to create the tx and rx half of [`CaptureConnection`] |
| 92 | + pub(crate) fn new() -> (CaptureConnectionExtension, Self) { |
| 93 | + let (tx, rx) = watch::channel(None); |
| 94 | + ( |
| 95 | + CaptureConnectionExtension { tx: Arc::new(tx) }, |
| 96 | + CaptureConnection { rx }, |
| 97 | + ) |
| 98 | + } |
| 99 | + |
| 100 | + /// Retrieve the connection metadata, if available |
| 101 | + pub fn connection_metadata(&self) -> impl Deref<Target = Option<Connected>> + '_ { |
| 102 | + self.rx.borrow() |
| 103 | + } |
| 104 | + |
| 105 | + /// Wait for the connection to be established |
| 106 | + /// |
| 107 | + /// If a connection was established, this will always return `Some(...)`. If the request never |
| 108 | + /// successfully connected (e.g. DNS resolution failure), this method will never return. |
| 109 | + pub async fn wait_for_connection_metadata( |
| 110 | + &mut self, |
| 111 | + ) -> impl Deref<Target = Option<Connected>> + '_ { |
| 112 | + if self.rx.borrow().is_some() { |
| 113 | + return self.rx.borrow(); |
| 114 | + } |
| 115 | + let _ = self.rx.changed().await; |
| 116 | + self.rx.borrow() |
| 117 | + } |
| 118 | +} |
| 119 | + |
| 120 | +#[cfg(all(test, not(miri)))] |
| 121 | +mod test { |
| 122 | + use super::*; |
| 123 | + |
| 124 | + #[test] |
| 125 | + fn test_sync_capture_connection() { |
| 126 | + let (tx, rx) = CaptureConnection::new(); |
| 127 | + assert!( |
| 128 | + rx.connection_metadata().is_none(), |
| 129 | + "connection has not been set" |
| 130 | + ); |
| 131 | + tx.set(&Connected::new().proxy(true)); |
| 132 | + assert_eq!( |
| 133 | + rx.connection_metadata() |
| 134 | + .as_ref() |
| 135 | + .expect("connected should be set") |
| 136 | + .is_proxied(), |
| 137 | + true |
| 138 | + ); |
| 139 | + |
| 140 | + // ensure it can be called multiple times |
| 141 | + assert_eq!( |
| 142 | + rx.connection_metadata() |
| 143 | + .as_ref() |
| 144 | + .expect("connected should be set") |
| 145 | + .is_proxied(), |
| 146 | + true |
| 147 | + ); |
| 148 | + } |
| 149 | + |
| 150 | + #[tokio::test] |
| 151 | + async fn async_capture_connection() { |
| 152 | + let (tx, mut rx) = CaptureConnection::new(); |
| 153 | + assert!( |
| 154 | + rx.connection_metadata().is_none(), |
| 155 | + "connection has not been set" |
| 156 | + ); |
| 157 | + let test_task = tokio::spawn(async move { |
| 158 | + assert_eq!( |
| 159 | + rx.wait_for_connection_metadata() |
| 160 | + .await |
| 161 | + .as_ref() |
| 162 | + .expect("connection should be set") |
| 163 | + .is_proxied(), |
| 164 | + true |
| 165 | + ); |
| 166 | + // can be awaited multiple times |
| 167 | + assert!( |
| 168 | + rx.wait_for_connection_metadata().await.is_some(), |
| 169 | + "should be awaitable multiple times" |
| 170 | + ); |
| 171 | + |
| 172 | + assert_eq!(rx.connection_metadata().is_some(), true); |
| 173 | + }); |
| 174 | + // can't be finished, we haven't set the connection yet |
| 175 | + assert_eq!(test_task.is_finished(), false); |
| 176 | + tx.set(&Connected::new().proxy(true)); |
| 177 | + |
| 178 | + assert!(test_task.await.is_ok()); |
| 179 | + } |
| 180 | + |
| 181 | + #[tokio::test] |
| 182 | + async fn capture_connection_sender_side_dropped() { |
| 183 | + let (tx, mut rx) = CaptureConnection::new(); |
| 184 | + assert!( |
| 185 | + rx.connection_metadata().is_none(), |
| 186 | + "connection has not been set" |
| 187 | + ); |
| 188 | + drop(tx); |
| 189 | + assert!(rx.wait_for_connection_metadata().await.is_none()); |
| 190 | + } |
| 191 | +} |
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