Make minor improvements to chat example.

examples/chat/src/main.rs

@@ -1,18 +1,17 @@
-//! Implements a chat server using async rocket and SSE.
-
 #[macro_use] extern crate rocket;
 
 #[cfg(test)] mod tests;
 
 use rocket::{State, Shutdown};
-use rocket::form::Form;
 use rocket::fs::{relative, FileServer};
+use rocket::form::Form;
 use rocket::response::stream::{EventStream, Event};
+use rocket::serde::{Serialize, Deserialize};
 use rocket::tokio::sync::broadcast::{channel, Sender, error::RecvError};
 use rocket::tokio::select;
-use rocket::serde::{Serialize, Deserialize};
 
-#[derive(Debug, PartialEq, Clone, FromForm, Deserialize, Serialize, UriDisplayQuery)]
+#[derive(Debug, Clone, FromForm, Serialize, Deserialize)]
+#[cfg_attr(test, derive(PartialEq, UriDisplayQuery))]
 #[serde(crate = "rocket::serde")]
 struct Message {
     #[field(validate = len(..30))]
@@ -22,9 +21,10 @@ struct Message {
     pub message: String,
 }
 
+/// Returns an infinite stream of server-sent events. Each event is a message
+/// pulled from a broadcast queue sent by the `post` handler.
 #[get("/events")]
 async fn events(queue: &State<Sender<Message>>, mut end: Shutdown) -> EventStream![] {
-    // Subscribe to messages and map it to an SSE stream
     let mut rx = queue.subscribe();
     EventStream! {
         loop {
@@ -42,6 +42,7 @@ async fn events(queue: &State<Sender<Message>>, mut end: Shutdown) -> EventStrea
     }
 }
 
+/// Receive a message from a form submission and broadcast it to any receivers.
 #[post("/message", data = "<form>")]
 fn post(form: Form<Message>, queue: &State<Sender<Message>>) {
     // A send 'fails' if there are no active subscribers. That's okay.

examples/chat/static/index.html

@@ -20,7 +20,7 @@
 
         <form id="new-room">
           <input type="text" name="name" id="name" autocomplete="off"
-              placeholder="new room..." maxlength="30"></input>
+              placeholder="new room..." maxlength="29"></input>
           <button type="submit">+</button>
         </form>
       </div>
@@ -37,7 +37,7 @@
         </div>
 
         <form id="new-message">
-          <input type="text" name="username" id="username" maxlength="20"
+          <input type="text" name="username" id="username" maxlength="19"
             placeholder="guest" autocomplete="off">
           <input type="text" name="message" id="message" autocomplete="off"
               placeholder="Send a message..." autofocus>