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| 1 | +// Copyright (c) 2018-2020 Sean McArthur |
| 2 | +// Licensed under the MIT license http://opensource.org/licenses/MIT |
| 3 | +// |
| 4 | +// port from https://github.com/seanmonstar/warp/blob/master/examples/sse_chat.rs |
| 5 | + |
| 6 | +use std::collections::HashMap; |
| 7 | +use std::sync::atomic::{AtomicUsize, Ordering}; |
| 8 | + |
| 9 | +use futures_util::{Stream, StreamExt, TryFutureExt, TryStreamExt}; |
| 10 | +use once_cell::sync::Lazy; |
| 11 | +use parking_lot::Mutex; |
| 12 | +use tokio::sync::mpsc; |
| 13 | +use tokio_stream::wrappers::UnboundedReceiverStream; |
| 14 | + |
| 15 | +use silent::prelude::*; |
| 16 | + |
| 17 | +type Users = Mutex<HashMap<usize, mpsc::UnboundedSender<Message>>>; |
| 18 | + |
| 19 | +static NEXT_USER_ID: AtomicUsize = AtomicUsize::new(1); |
| 20 | +static ONLINE_USERS: Lazy<Users> = Lazy::new(Users::default); |
| 21 | + |
| 22 | +fn main() { |
| 23 | + logger::fmt().with_max_level(Level::INFO).init(); |
| 24 | + |
| 25 | + let route = Route::new("").get(index).append( |
| 26 | + Route::new("chat") |
| 27 | + .handler( |
| 28 | + Method::GET, |
| 29 | + HandlerWrapperResponse::new(user_connected).arc(), |
| 30 | + ) |
| 31 | + .append( |
| 32 | + Route::new("<id:int>") |
| 33 | + .handler(Method::POST, HandlerWrapperResponse::new(chat_send).arc()), |
| 34 | + ), |
| 35 | + ); |
| 36 | + |
| 37 | + Server::new() |
| 38 | + .bind("0.0.0.0:8001".parse().unwrap()) |
| 39 | + .bind_route(route) |
| 40 | + .run(); |
| 41 | +} |
| 42 | + |
| 43 | +#[derive(Debug)] |
| 44 | +enum Message { |
| 45 | + UserId(usize), |
| 46 | + Reply(String), |
| 47 | +} |
| 48 | + |
| 49 | +async fn chat_send(req: Request) -> Result<Response> { |
| 50 | + let my_id = req.get_path_params::<i32>("id")?; |
| 51 | + let msg = "hello"; |
| 52 | + user_message(my_id as usize, msg); |
| 53 | + Ok(Response::empty()) |
| 54 | +} |
| 55 | + |
| 56 | +async fn user_connected(_req: Request) -> Result<Response> { |
| 57 | + // Use a counter to assign a new unique ID for this user. |
| 58 | + let my_id = NEXT_USER_ID.fetch_add(1, Ordering::Relaxed); |
| 59 | + |
| 60 | + info!("new chat user: {}", my_id); |
| 61 | + |
| 62 | + // Use an unbounded channel to handle buffering and flushing of messages |
| 63 | + // to the event source... |
| 64 | + let (tx, rx) = mpsc::unbounded_channel(); |
| 65 | + let rx = UnboundedReceiverStream::new(rx); |
| 66 | + |
| 67 | + tx.send(Message::UserId(my_id)) |
| 68 | + // rx is right above, so this cannot fail |
| 69 | + .unwrap(); |
| 70 | + |
| 71 | + // Save the sender in our list of connected users. |
| 72 | + ONLINE_USERS.lock().insert(my_id, tx); |
| 73 | + |
| 74 | + // Convert messages into Server-Sent Events and returns resulting stream. |
| 75 | + let stream = rx.map(|msg| match msg { |
| 76 | + Message::UserId(my_id) => { |
| 77 | + warn!("user {} disconnected", my_id); |
| 78 | + Ok(SSEEvent::default().event("user").data(my_id.to_string())) |
| 79 | + } |
| 80 | + Message::Reply(reply) => { |
| 81 | + warn!("sse_reply: {}", reply); |
| 82 | + Ok(SSEEvent::default().data(reply)) |
| 83 | + } |
| 84 | + }); |
| 85 | + let res = sse_reply(stream); |
| 86 | + Ok(res) |
| 87 | +} |
| 88 | + |
| 89 | +fn user_message(my_id: usize, msg: &str) { |
| 90 | + let new_msg = format!("<User#{my_id}>: {msg}"); |
| 91 | + |
| 92 | + // New message from this user, send it to everyone else (except same uid)... |
| 93 | + // |
| 94 | + // We use `retain` instead of a for loop so that we can reap any user that |
| 95 | + // appears to have disconnected. |
| 96 | + ONLINE_USERS.lock().retain(|uid, tx| { |
| 97 | + if my_id == *uid { |
| 98 | + // don't send to same user, but do retain |
| 99 | + true |
| 100 | + } else { |
| 101 | + // If not `is_ok`, the SSE stream is gone, and so don't retain |
| 102 | + tx.send(Message::Reply(new_msg.clone())).is_ok() |
| 103 | + } |
| 104 | + }); |
| 105 | +} |
| 106 | + |
| 107 | +async fn index<'a>(_req: Request) -> Result<&'a str> { |
| 108 | + Ok(INDEX_HTML) |
| 109 | +} |
| 110 | + |
| 111 | +static INDEX_HTML: &str = r#" |
| 112 | +<!DOCTYPE html> |
| 113 | +<html> |
| 114 | + <head> |
| 115 | + <title>SSE Chat</title> |
| 116 | + </head> |
| 117 | + <body> |
| 118 | + <h1>SSE chat</h1> |
| 119 | + <div id="chat"> |
| 120 | + <p><em>Connecting...</em></p> |
| 121 | + </div> |
| 122 | + <input type="text" id="text" /> |
| 123 | + <button type="button" id="send">Send</button> |
| 124 | + <script type="text/javascript"> |
| 125 | + var uri = 'http://' + location.host + '/chat'; |
| 126 | + var sse = new EventSource(uri); |
| 127 | + function message(data) { |
| 128 | + var line = document.createElement('p'); |
| 129 | + line.innerText = data; |
| 130 | + chat.appendChild(line); |
| 131 | + } |
| 132 | + sse.onopen = function() { |
| 133 | + chat.innerHTML = "<p><em>Connected!</em></p>"; |
| 134 | + } |
| 135 | + var user_id; |
| 136 | + sse.addEventListener("user", function(msg) { |
| 137 | + user_id = msg.data; |
| 138 | + }); |
| 139 | + sse.onmessage = function(msg) { |
| 140 | + message(msg.data); |
| 141 | + }; |
| 142 | + send.onclick = function() { |
| 143 | + var msg = text.value; |
| 144 | + var xhr = new XMLHttpRequest(); |
| 145 | + xhr.open("POST", uri + '/' + user_id, true); |
| 146 | + xhr.send(msg); |
| 147 | + text.value = ''; |
| 148 | + message('<You>: ' + msg); |
| 149 | + }; |
| 150 | + </script> |
| 151 | + </body> |
| 152 | +</html> |
| 153 | +"#; |
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