fastwebsockets 0.3.0

A fast RFC6455 WebSocket server implementation
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
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

// Port of hyper_tunstenite for fastwebsockets.
// https://github.com/de-vri-es/hyper-tungstenite-rs
//
// Copyright 2021, Maarten de Vries maarten@de-vri.es
// BSD 2-Clause "Simplified" License
//
// Copyright 2023 Divy Srivastava <dj.srivastava23@gmail.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use base64;
use base64::engine::general_purpose::STANDARD;
use base64::Engine;
use hyper::Body;
use hyper::Request;
use hyper::Response;
use pin_project::pin_project;
use sha1::Digest;
use sha1::Sha1;
use std::pin::Pin;
use std::task::Context;
use std::task::Poll;

use crate::Role;
use crate::WebSocket;

fn sec_websocket_protocol(key: &[u8]) -> String {
  let mut sha1 = Sha1::new();
  sha1.update(key);
  sha1.update(b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"); // magic string
  let result = sha1.finalize();
  STANDARD.encode(&result[..])
}

type Error = Box<dyn std::error::Error + Send + Sync>;

/// A future that resolves to a websocket stream when the associated HTTP upgrade completes.
#[pin_project]
#[derive(Debug)]
pub struct UpgradeFut {
  #[pin]
  inner: hyper::upgrade::OnUpgrade,
}

/// Try to upgrade a received `hyper::Request` to a websocket connection.
///
/// The function returns a HTTP response and a future that resolves to the websocket stream.
/// The response body *MUST* be sent to the client before the future can be resolved.
///
/// This functions checks `Sec-WebSocket-Key` and `Sec-WebSocket-Version` headers.
/// It does not inspect the `Origin`, `Sec-WebSocket-Protocol` or `Sec-WebSocket-Extensions` headers.
/// You can inspect the headers manually before calling this function,
/// and modify the response headers appropriately.
///
/// This function also does not look at the `Connection` or `Upgrade` headers.
/// To check if a request is a websocket upgrade request, you can use [`is_upgrade_request`].
/// Alternatively you can inspect the `Connection` and `Upgrade` headers manually.
///
pub fn upgrade<B>(
  mut request: impl std::borrow::BorrowMut<Request<B>>,
) -> Result<(Response<Body>, UpgradeFut), Error> {
  let request = request.borrow_mut();

  let key = request
    .headers()
    .get("Sec-WebSocket-Key")
    .ok_or("Sec-WebSocket-Key header is missing")?;
  if request
    .headers()
    .get("Sec-WebSocket-Version")
    .map(|v| v.as_bytes())
    != Some(b"13")
  {
    return Err("Sec-WebSocket-Version must be 13".into());
  }

  let response = Response::builder()
    .status(hyper::StatusCode::SWITCHING_PROTOCOLS)
    .header(hyper::header::CONNECTION, "upgrade")
    .header(hyper::header::UPGRADE, "websocket")
    .header(
      "Sec-WebSocket-Accept",
      &sec_websocket_protocol(key.as_bytes()),
    )
    .body(Body::from("switching to websocket protocol"))
    .expect("bug: failed to build response");

  let stream = UpgradeFut {
    inner: hyper::upgrade::on(request),
  };

  Ok((response, stream))
}

/// Check if a request is a websocket upgrade request.
///
/// If the `Upgrade` header lists multiple protocols,
/// this function returns true if of them are `"websocket"`,
/// If the server supports multiple upgrade protocols,
/// it would be more appropriate to try each listed protocol in order.
pub fn is_upgrade_request<B>(request: &hyper::Request<B>) -> bool {
  header_contains_value(request.headers(), hyper::header::CONNECTION, "Upgrade")
    && header_contains_value(
      request.headers(),
      hyper::header::UPGRADE,
      "websocket",
    )
}

/// Check if there is a header of the given name containing the wanted value.
fn header_contains_value(
  headers: &hyper::HeaderMap,
  header: impl hyper::header::AsHeaderName,
  value: impl AsRef<[u8]>,
) -> bool {
  let value = value.as_ref();
  for header in headers.get_all(header) {
    if header
      .as_bytes()
      .split(|&c| c == b',')
      .any(|x| trim(x).eq_ignore_ascii_case(value))
    {
      return true;
    }
  }
  false
}

fn trim(data: &[u8]) -> &[u8] {
  trim_end(trim_start(data))
}

fn trim_start(data: &[u8]) -> &[u8] {
  if let Some(start) = data.iter().position(|x| !x.is_ascii_whitespace()) {
    &data[start..]
  } else {
    b""
  }
}

fn trim_end(data: &[u8]) -> &[u8] {
  if let Some(last) = data.iter().rposition(|x| !x.is_ascii_whitespace()) {
    &data[..last + 1]
  } else {
    b""
  }
}

impl std::future::Future for UpgradeFut {
  type Output = Result<WebSocket<hyper::upgrade::Upgraded>, Error>;

  fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
    let this = self.project();
    let upgraded = match this.inner.poll(cx) {
      Poll::Pending => return Poll::Pending,
      Poll::Ready(x) => x,
    };

    Poll::Ready(Ok(WebSocket::after_handshake(upgraded?, Role::Server)))
  }
}