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| 1 | +#![feature(async_await)] |
| 2 | +#![deny(warnings)] |
| 3 | + |
| 4 | +// Note: `hyper::upgrade` docs link to this upgrade. |
| 5 | +use std::str; |
| 6 | + |
| 7 | +use tokio::sync::oneshot; |
| 8 | +use tokio::io::{AsyncReadExt, AsyncWriteExt}; |
| 9 | + |
| 10 | +use hyper::{Body, Client, Request, Response, Server, StatusCode}; |
| 11 | +use hyper::header::{UPGRADE, HeaderValue}; |
| 12 | +use hyper::service::{make_service_fn, service_fn}; |
| 13 | +use hyper::upgrade::Upgraded; |
| 14 | +use std::net::SocketAddr; |
| 15 | + |
| 16 | +// A simple type alias so as to DRY. |
| 17 | +type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>; |
| 18 | + |
| 19 | +/// Handle server-side I/O after HTTP upgraded. |
| 20 | +async fn server_upgraded_io(mut upgraded: Upgraded) -> Result<()> { |
| 21 | + // we have an upgraded connection that we can read and |
| 22 | + // write on directly. |
| 23 | + // |
| 24 | + // since we completely control this example, we know exactly |
| 25 | + // how many bytes the client will write, so just read exact... |
| 26 | + let mut vec = vec![0; 7]; |
| 27 | + upgraded.read_exact(&mut vec).await?; |
| 28 | + println!("server[foobar] recv: {:?}", str::from_utf8(&vec)); |
| 29 | + |
| 30 | + // and now write back the server 'foobar' protocol's |
| 31 | + // response... |
| 32 | + upgraded.write_all(b"barr=foo").await?; |
| 33 | + println!("server[foobar] sent"); |
| 34 | + Ok(()) |
| 35 | +} |
| 36 | + |
| 37 | +/// Our server HTTP handler to initiate HTTP upgrades. |
| 38 | +async fn server_upgrade(req: Request<Body>) -> Result<Response<Body>> { |
| 39 | + let mut res = Response::new(Body::empty()); |
| 40 | + |
| 41 | + // Send a 400 to any request that doesn't have |
| 42 | + // an `Upgrade` header. |
| 43 | + if !req.headers().contains_key(UPGRADE) { |
| 44 | + *res.status_mut() = StatusCode::BAD_REQUEST; |
| 45 | + return Ok(res); |
| 46 | + } |
| 47 | + |
| 48 | + // Setup a future that will eventually receive the upgraded |
| 49 | + // connection and talk a new protocol, and spawn the future |
| 50 | + // into the runtime. |
| 51 | + // |
| 52 | + // Note: This can't possibly be fulfilled until the 101 response |
| 53 | + // is returned below, so it's better to spawn this future instead |
| 54 | + // waiting for it to complete to then return a response. |
| 55 | + hyper::rt::spawn(async move { |
| 56 | + match req.into_body().on_upgrade().await { |
| 57 | + Ok(upgraded) => { |
| 58 | + if let Err(e) = server_upgraded_io(upgraded).await { |
| 59 | + eprintln!("server foobar io error: {}", e) |
| 60 | + }; |
| 61 | + } |
| 62 | + Err(e) => eprintln!("upgrade error: {}", e) |
| 63 | + } |
| 64 | + }); |
| 65 | + |
| 66 | + // Now return a 101 Response saying we agree to the upgrade to some |
| 67 | + // made-up 'foobar' protocol. |
| 68 | + *res.status_mut() = StatusCode::SWITCHING_PROTOCOLS; |
| 69 | + res.headers_mut().insert(UPGRADE, HeaderValue::from_static("foobar")); |
| 70 | + Ok(res) |
| 71 | +} |
| 72 | + |
| 73 | +/// Handle client-side I/O after HTTP upgraded. |
| 74 | +async fn client_upgraded_io(mut upgraded: Upgraded) -> Result<()> { |
| 75 | + // We've gotten an upgraded connection that we can read |
| 76 | + // and write directly on. Let's start out 'foobar' protocol. |
| 77 | + upgraded.write_all(b"foo=bar").await?; |
| 78 | + println!("client[foobar] sent"); |
| 79 | + |
| 80 | + let mut vec = Vec::new(); |
| 81 | + upgraded.read_to_end(&mut vec).await?; |
| 82 | + println!("client[foobar] recv: {:?}", str::from_utf8(&vec)); |
| 83 | + |
| 84 | + Ok(()) |
| 85 | +} |
| 86 | + |
| 87 | +/// Our client HTTP handler to initiate HTTP upgrades. |
| 88 | +async fn client_upgrade_request(addr: SocketAddr) -> Result<()> { |
| 89 | + let req = Request::builder() |
| 90 | + .uri(format!("http://{}/", addr)) |
| 91 | + .header(UPGRADE, "foobar") |
| 92 | + .body(Body::empty()) |
| 93 | + .unwrap(); |
| 94 | + |
| 95 | + let res = Client::new().request(req).await?; |
| 96 | + if res.status() != StatusCode::SWITCHING_PROTOCOLS { |
| 97 | + panic!("Our server didn't upgrade: {}", res.status()); |
| 98 | + } |
| 99 | + |
| 100 | + match res.into_body().on_upgrade().await { |
| 101 | + Ok(upgraded) => { |
| 102 | + if let Err(e) = client_upgraded_io(upgraded).await { |
| 103 | + eprintln!("client foobar io error: {}", e) |
| 104 | + }; |
| 105 | + } |
| 106 | + Err(e) => eprintln!("upgrade error: {}", e) |
| 107 | + } |
| 108 | + |
| 109 | + Ok(()) |
| 110 | +} |
| 111 | + |
| 112 | +#[hyper::rt::main] |
| 113 | +async fn main() { |
| 114 | + // For this example, we just make a server and our own client to talk to |
| 115 | + // it, so the exact port isn't important. Instead, let the OS give us an |
| 116 | + // unused port. |
| 117 | + let addr = ([127, 0, 0, 1], 0).into(); |
| 118 | + |
| 119 | + let make_service = make_service_fn(|_| async { |
| 120 | + Ok::<_, hyper::Error>(service_fn(server_upgrade)) |
| 121 | + }); |
| 122 | + |
| 123 | + let server = Server::bind(&addr) |
| 124 | + .serve(make_service); |
| 125 | + |
| 126 | + // We need the assigned address for the client to send it messages. |
| 127 | + let addr = server.local_addr(); |
| 128 | + |
| 129 | + // For this example, a oneshot is used to signal that after 1 request, |
| 130 | + // the server should be shutdown. |
| 131 | + let (tx, rx) = oneshot::channel::<()>(); |
| 132 | + let server = server |
| 133 | + .with_graceful_shutdown(async { |
| 134 | + rx.await.ok(); |
| 135 | + }); |
| 136 | + |
| 137 | + // Spawn server on the default executor, |
| 138 | + // which is usually a thread-pool from tokio default runtime. |
| 139 | + hyper::rt::spawn(async { |
| 140 | + if let Err(e) = server.await { |
| 141 | + eprintln!("server error: {}", e); |
| 142 | + } |
| 143 | + }); |
| 144 | + |
| 145 | + // Client requests a HTTP connection upgrade. |
| 146 | + let request = client_upgrade_request(addr.clone()); |
| 147 | + if let Err(e) = request.await { |
| 148 | + eprintln!("client error: {}", e); |
| 149 | + } |
| 150 | + |
| 151 | + // Complete the oneshot so that the server stops |
| 152 | + // listening and the process can close down. |
| 153 | + let _ = tx.send(()); |
| 154 | +} |
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