soketto/handshake/
http.rs

1// Copyright (c) 2021 Parity Technologies (UK) Ltd.
2//
3// Licensed under the Apache License, Version 2.0
4// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
5// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
6// option. All files in the project carrying such notice may not be copied,
7// modified, or distributed except according to those terms.
8
9/*!
10This module somewhat mirrors [`crate::handshake::server`], except it's focus is on working
11with [`http::Request`] and [`http::Response`] types, making it easier to integrate with
12external web servers such as Hyper.
13
14See `examples/hyper_server.rs` from this crate's repository for example usage.
15*/
16
17use super::{WebSocketKey, SEC_WEBSOCKET_EXTENSIONS};
18use crate::connection::{self, Mode};
19use crate::extension::Extension;
20use crate::handshake;
21use bytes::BytesMut;
22use futures::prelude::*;
23use http::{header, HeaderMap, Response};
24use std::mem;
25
26/// A re-export of [`handshake::Error`].
27pub type Error = handshake::Error;
28
29/// Websocket handshake server. This is similar to [`handshake::Server`], but it is
30/// focused on performing the WebSocket handshake using a provided [`http::Request`], as opposed
31/// to decoding the request internally.
32pub struct Server {
33	// Extensions the server supports.
34	extensions: Vec<Box<dyn Extension + Send>>,
35	// Encoding/decoding buffer.
36	buffer: BytesMut,
37}
38
39impl Server {
40	/// Create a new server handshake.
41	pub fn new() -> Self {
42		Server { extensions: Vec::new(), buffer: BytesMut::new() }
43	}
44
45	/// Override the buffer to use for request/response handling.
46	pub fn set_buffer(&mut self, b: BytesMut) -> &mut Self {
47		self.buffer = b;
48		self
49	}
50
51	/// Extract the buffer.
52	pub fn take_buffer(&mut self) -> BytesMut {
53		mem::take(&mut self.buffer)
54	}
55
56	/// Add an extension the server supports.
57	pub fn add_extension(&mut self, e: Box<dyn Extension + Send>) -> &mut Self {
58		self.extensions.push(e);
59		self
60	}
61
62	/// Get back all extensions.
63	pub fn drain_extensions(&mut self) -> impl Iterator<Item = Box<dyn Extension + Send>> + '_ {
64		self.extensions.drain(..)
65	}
66
67	/// Attempt to interpret the provided [`http::Request`] as a WebSocket Upgrade request. If successful, this
68	/// returns an [`http::Response`] that should be returned to the client to complete the handshake.
69	pub fn receive_request<B>(&mut self, req: &http::Request<B>) -> Result<http::Response<()>, Error> {
70		if !is_upgrade_request(&req) {
71			return Err(Error::InvalidSecWebSocketAccept);
72		}
73
74		let key = match req.headers().get("Sec-WebSocket-Key") {
75			Some(key) => key,
76			None => {
77				return Err(Error::HeaderNotFound("Sec-WebSocket-Key".into()).into());
78			}
79		};
80
81		if req.headers().get("Sec-WebSocket-Version").map(|v| v.as_bytes()) != Some(b"13") {
82			return Err(Error::HeaderNotFound("Sec-WebSocket-Version".into()).into());
83		}
84
85		// Pull out the Sec-WebSocket-Key and generate the appropriate response to it.
86		let key: &WebSocketKey = match key.as_bytes().try_into() {
87			Ok(key) => key,
88			Err(_) => return Err(Error::InvalidSecWebSocketAccept),
89		};
90		let accept_key = handshake::generate_accept_key(key);
91
92		// Get extension information out of the request as we'll need this as well.
93		let extension_config = req
94			.headers()
95			.iter()
96			.filter(|&(name, _)| name.as_str().eq_ignore_ascii_case(SEC_WEBSOCKET_EXTENSIONS))
97			.map(|(_, value)| Ok(std::str::from_utf8(value.as_bytes())?.to_string()))
98			.collect::<Result<Vec<_>, Error>>()?;
99
100		// Attempt to set the extension configuration params that the client requested.
101		for config_str in &extension_config {
102			handshake::configure_extensions(&mut self.extensions, &config_str)?;
103		}
104
105		// Build a response that should be sent back to the client to acknowledge the upgrade.
106		let mut response = Response::builder()
107			.status(http::StatusCode::SWITCHING_PROTOCOLS)
108			.header(http::header::CONNECTION, "upgrade")
109			.header(http::header::UPGRADE, "websocket")
110			.header("Sec-WebSocket-Accept", &accept_key[..]);
111
112		// Tell the client about the agreed-upon extension configuration. We reuse code to build up the
113		// extension header value, but that does make this a little more clunky.
114		if !self.extensions.is_empty() {
115			let mut buf = bytes::BytesMut::new();
116			let enabled_extensions = self.extensions.iter().filter(|e| e.is_enabled()).peekable();
117			handshake::append_extension_header_value(enabled_extensions, &mut buf);
118			response = response.header("Sec-WebSocket-Extensions", buf.as_ref());
119		}
120
121		let response = response.body(()).expect("bug: failed to build response");
122		Ok(response)
123	}
124
125	/// Turn this handshake into a [`connection::Builder`].
126	pub fn into_builder<T: AsyncRead + AsyncWrite + Unpin>(mut self, socket: T) -> connection::Builder<T> {
127		let mut builder = connection::Builder::new(socket, Mode::Server);
128		builder.set_buffer(self.buffer);
129		builder.add_extensions(self.extensions.drain(..));
130		builder
131	}
132}
133
134/// Check if an [`http::Request`] looks like a valid websocket upgrade request.
135pub fn is_upgrade_request<B>(request: &http::Request<B>) -> bool {
136	header_contains_value(request.headers(), header::CONNECTION, b"upgrade")
137		&& header_contains_value(request.headers(), header::UPGRADE, b"websocket")
138}
139
140// Check if there is a header of the given name containing the wanted value.
141fn header_contains_value(headers: &HeaderMap, header: header::HeaderName, value: &[u8]) -> bool {
142	pub fn trim(x: &[u8]) -> &[u8] {
143		let from = match x.iter().position(|x| !x.is_ascii_whitespace()) {
144			Some(i) => i,
145			None => return &[],
146		};
147		let to = x.iter().rposition(|x| !x.is_ascii_whitespace()).unwrap();
148		&x[from..=to]
149	}
150
151	for header in headers.get_all(header) {
152		if header.as_bytes().split(|&c| c == b',').any(|x| trim(x).eq_ignore_ascii_case(value)) {
153			return true;
154		}
155	}
156	false
157}
soketto/handshake/http.rs

soketto/handshake/
http.rs
