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// Copyright (c) 2016 The Rouille developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.
use std::io;
use std::io::Write;
use std::mem;
use std::sync::mpsc::Sender;
use ReadWrite;
use Upgrade;
use websocket::low_level;
/// A successful websocket. An open channel of communication. Implements `Read` and `Write`.
pub struct Websocket {
// The socket. `None` if closed.
socket: Option<Box<dyn ReadWrite + Send>>,
// The websocket state machine.
state_machine: low_level::StateMachine,
// True if the fragmented message currently being processed is binary. False if string. Pings
// are excluded.
current_message_binary: bool,
// Buffer for the fragmented message currently being processed. Pings are excluded.
current_message_payload: Vec<u8>,
// Opcode of the fragment currently being processed.
current_frame_opcode: u8,
// Fin flag of the fragment currently being processed.
current_frame_fin: bool,
// Data of the fragment currently being processed.
current_frame_payload: Vec<u8>,
// Queue of the messages that are going to be returned by `next()`.
messages_in_queue: Vec<Message>,
}
/// A message produced by a websocket connection.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Message {
/// Text data. If the client is in Javascript, this happens when the client called `send()`
/// with a string.
Text(String),
/// Binary data. If the client is in Javascript, this happens when the client called `send()`
/// with a blob or an arraybuffer.
Binary(Vec<u8>),
}
/// Error that can happen when sending a message to the client.
#[derive(Debug)]
pub enum SendError {
/// Failed to transfer the message on the socket.
IoError(io::Error),
/// The websocket connection is closed.
Closed,
}
impl From<io::Error> for SendError {
#[inline]
fn from(err: io::Error) -> SendError {
SendError::IoError(err)
}
}
impl Websocket {
/// Sends text data over the websocket.
///
/// Returns an error if the message didn't send correctly or if the connection is closed.
///
/// If the client is in javascript, the message will contain a string.
#[inline]
pub fn send_text(&mut self, data: &str) -> Result<(), SendError> {
let socket = match self.socket {
Some(ref mut s) => s,
None => return Err(SendError::Closed),
};
try!(send(data.as_bytes(), Write::by_ref(socket), 0x1));
Ok(())
}
/// Sends binary data over the websocket.
///
/// Returns an error if the message didn't send correctly or if the connection is closed.
///
/// If the client is in javascript, the message will contain a blob or an arraybuffer.
#[inline]
pub fn send_binary(&mut self, data: &[u8]) -> Result<(), SendError> {
let socket = match self.socket {
Some(ref mut s) => s,
None => return Err(SendError::Closed),
};
try!(send(data, Write::by_ref(socket), 0x2));
Ok(())
}
/// Returns `true` if the websocket has been closed by either the client (voluntarily or not)
/// or by the server (if the websocket protocol was violated).
#[inline]
pub fn is_closed(&self) -> bool {
self.socket.is_none()
}
// TODO: give access to close reason
}
impl Upgrade for Sender<Websocket> {
fn build(&mut self, socket: Box<dyn ReadWrite + Send>) {
let websocket = Websocket {
socket: Some(socket),
state_machine: low_level::StateMachine::new(),
current_message_binary: false,
current_message_payload: Vec::new(),
current_frame_opcode: 0,
current_frame_fin: false,
current_frame_payload: Vec::new(),
messages_in_queue: Vec::new(),
};
let _ = self.send(websocket);
}
}
impl Iterator for Websocket {
type Item = Message;
fn next(&mut self) -> Option<Message> {
loop {
// If the socket is `None`, the connection has been closed.
if self.socket.is_none() {
return None;
}
// There may be some messages waiting to be processed.
if !self.messages_in_queue.is_empty() {
return Some(self.messages_in_queue.remove(0));
}
// Read `n` bytes in `buf`.
let mut buf = [0; 256];
let n = match self.socket.as_mut().unwrap().read(&mut buf) {
Ok(n) if n == 0 => {
// Read returning zero means EOF
self.socket = None;
return None;
}
Ok(n) => n,
Err(ref err) if err.kind() == io::ErrorKind::Interrupted => 0,
Err(_) => {
self.socket = None;
return None;
}
};
// Fill `messages_in_queue` by analyzing the packets.
for element in self.state_machine.feed(&buf[0..n]) {
match element {
low_level::Element::FrameStart { fin, opcode, .. } => {
debug_assert!(self.current_frame_payload.is_empty());
self.current_frame_fin = fin;
self.current_frame_opcode = opcode;
}
low_level::Element::Data {
data,
last_in_frame,
} => {
// Under normal circumstances we just handle data by pushing it to
// `current_frame_payload`.
self.current_frame_payload.extend(data);
// But if the frame is finished we additionnally need to dispatch it.
if last_in_frame {
match self.current_frame_opcode {
// Frame is a continuation of the current message.
0x0 => {
self.current_message_payload
.append(&mut self.current_frame_payload);
// If the message is finished, dispatch it.
if self.current_frame_fin {
let binary = mem::replace(
&mut self.current_message_payload,
Vec::new(),
);
if self.current_message_binary {
self.messages_in_queue.push(Message::Binary(binary));
} else {
let string = match String::from_utf8(binary) {
Ok(s) => s,
Err(_) => {
// Closing connection because text wasn't UTF-8
let _ = send(
b"1007 Invalid UTF-8 encoding",
Write::by_ref(
self.socket.as_mut().unwrap(),
),
0x8,
);
self.socket = None;
return None;
}
};
self.messages_in_queue.push(Message::Text(string));
}
}
}
// Frame is an individual text frame.
0x1 => {
// If we're in the middle of a message, this frame is invalid
// and we need to close.
if !self.current_message_payload.is_empty() {
let _ = send(
b"1002 Expected continuation frame",
Write::by_ref(self.socket.as_mut().unwrap()),
0x8,
);
self.socket = None;
return None;
}
if self.current_frame_fin {
// There's only one frame in this message.
let binary = mem::replace(
&mut self.current_frame_payload,
Vec::new(),
);
let string = match String::from_utf8(binary) {
Ok(s) => s,
Err(_err) => {
// Closing connection because text wasn't UTF-8
let _ = send(
b"1007 Invalid UTF-8 encoding",
Write::by_ref(self.socket.as_mut().unwrap()),
0x8,
);
self.socket = None;
return None;
}
};
self.messages_in_queue.push(Message::Text(string));
} else {
// Start of a fragmented message.
self.current_message_binary = false;
self.current_message_payload
.append(&mut self.current_frame_payload);
}
}
// Frame is an individual binary frame.
0x2 => {
// If we're in the middle of a message, this frame is invalid
// and we need to close.
if !self.current_message_payload.is_empty() {
let _ = send(
b"1002 Expected continuation frame",
Write::by_ref(self.socket.as_mut().unwrap()),
0x8,
);
self.socket = None;
return None;
}
if self.current_frame_fin {
let binary = mem::replace(
&mut self.current_frame_payload,
Vec::new(),
);
self.messages_in_queue.push(Message::Binary(binary));
} else {
// Start of a fragmented message.
self.current_message_binary = true;
self.current_message_payload
.append(&mut self.current_frame_payload);
}
}
// Close request.
0x8 => {
// We need to send a confirmation.
let _ = send(
&self.current_frame_payload,
Write::by_ref(self.socket.as_mut().unwrap()),
0x8,
);
// Since the packets are always received in order, and since
// the server is considered dead as soon as it sends the
// confirmation, we have no risk of losing packets.
self.socket = None;
return None;
}
// Ping.
0x9 => {
// Send the pong.
let _ = send(
&self.current_frame_payload,
Write::by_ref(self.socket.as_mut().unwrap()),
0xA,
);
}
// Pong. We ignore this as there's nothing to do.
0xA => {}
// Unknown opcode means error and close.
_ => {
let _ = send(
b"Unknown opcode",
Write::by_ref(self.socket.as_mut().unwrap()),
0x8,
);
self.socket = None;
return None;
}
}
self.current_frame_payload.clear();
}
}
low_level::Element::Error { desc } => {
// The low level layer signaled an error. Sending it to client and closing.
let _ = send(
desc.as_bytes(),
Write::by_ref(self.socket.as_mut().unwrap()),
0x8,
);
self.socket = None;
return None;
}
}
}
}
}
}
// Sends a mesage to a websocket.
// TODO: message fragmentation?
fn send<W: Write>(data: &[u8], mut dest: W, opcode: u8) -> io::Result<()> {
// Write the opcode
assert!(opcode <= 0xf);
let first_byte = 0x80 | opcode;
try!(dest.write_all(&[first_byte]));
// Write the length
if data.len() >= 65536 {
try!(dest.write_all(&[127u8]));
let len = data.len() as u64;
assert!(len < 0x8000_0000_0000_0000);
let len1 = (len >> 56) as u8;
let len2 = (len >> 48) as u8;
let len3 = (len >> 40) as u8;
let len4 = (len >> 32) as u8;
let len5 = (len >> 24) as u8;
let len6 = (len >> 16) as u8;
let len7 = (len >> 8) as u8;
let len8 = (len >> 0) as u8;
try!(dest.write_all(&[len1, len2, len3, len4, len5, len6, len7, len8]));
} else if data.len() >= 126 {
try!(dest.write_all(&[126u8]));
let len = data.len() as u16;
let len1 = (len >> 8) as u8;
let len2 = len as u8;
try!(dest.write_all(&[len1, len2]));
} else {
try!(dest.write_all(&[data.len() as u8]));
}
// Write the data
try!(dest.write_all(data));
try!(dest.flush());
Ok(())
}