Use SSE for get_guilds

src/routes/get_guilds.rs

@@ -1,35 +1,34 @@
-use std::collections::HashMap;
-
 use poise::serenity_prelude::Http;
-use rocket::{http::{CookieJar, Status}, State};
-use rocket::serde::json::Json;
+use rocket::{http::CookieJar, State};
+use rocket::response::stream::{Event, EventStream};
 
 use crate::{cookies::user::USER_ID_COOKIE, models::Settings};
 
 // TODO: Incrementally send guilds
 #[get("/get_guilds")]
-pub async fn get_guilds(
-    cookies: &CookieJar<'_>,
-    settings: &State<Settings>,
-    http: &State<Http>,
-) -> Result<Json<HashMap<u64, bool>>, Status> {
-    let user_id: u64 = match cookies.get_private(USER_ID_COOKIE) {
-        Some(id) => match id.value().parse() {
-            Ok(id) => id,
-            Err(_) => return Err(Status::BadRequest),
-        },
-        None => return Err(Status::Unauthorized),
-    };
-    Ok(Json({
-        let mut guild_statuses = HashMap::with_capacity(settings.guilds.len());
+pub async fn get_guilds<'a>(
+    cookies: &'a CookieJar<'_>,
+    settings: &'a State<Settings>,
+    http: &'a State<Http>,
+) -> EventStream![Event + 'a] {
+    // EventStream![] is shorthand for EventStream[Event],
+    // but we need to pass in a lifetime parameter.
+    EventStream! {
+        // TODO: Proper error handling
+        let user_id: u64 = match cookies.get_private(USER_ID_COOKIE) {
+            Some(id) => match id.value().parse() {
+                Ok(id) => id,
+                Err(_) => panic!("BadRequest"),
+                // Err(_) => return Err(Status::BadRequest),
+            },
+            None => panic!("Unauthorized"),
+            // None => return Err(Status::Unauthorized),
+        };
         for guild in &settings.guilds {
-            guild_statuses.insert(guild.id, {
-                if guild.hidden {
-                    continue;
-                }
-                http.get_member(guild.id, user_id).await.is_ok()
-            });
+            if guild.hidden {
+                continue;
+            }
+            yield Event::data(format!("{},{}", guild.id, http.get_member(guild.id, user_id).await.is_ok()));
         }
-        guild_statuses
-    }))
+    }
 }

templates/modal.html.tera

@@ -24,11 +24,43 @@
 const dialog = document.querySelector("dialog");
 // Fetch guilds
 let guilds = null;
+let is_in_participating_server = null;
 const getGuilds = async () => {
     if (guilds === null) {
-        const response = await fetch("/get_guilds");
-        const raw_json = await response.text()
-        guilds = JSON.parse(raw_json);
+        // Create the guilds dictionary object
+        guilds = {};
+
+        // Create an EventSource object to listen to SSE events
+        const eventSource = new EventSource('/get_guilds');
+
+        // Event listener for 'message' events
+        eventSource.addEventListener('message', event => {
+            // Parse the data received from the event
+            const [id, is_member] = event.data.split(',');
+
+            // Add the key-value pair to the guilds dictionary
+            guilds[id] = is_member === 'true';
+
+            if (guilds[id]) {
+                setJoined(id);
+                is_in_participating_server = true;
+            }
+        });
+
+        // Function to block execution until SSE events are done
+        function waitForSSE() {
+            return new Promise(resolve => {
+                // Event listener for 'error' event
+                // For some reason errors when completing
+                eventSource.addEventListener('error', () => {
+                    eventSource.close();
+                    resolve();
+                });
+            });
+        }
+
+        // Call the function to block execution until SSE events are done
+        await waitForSSE()
     }
     return guilds;
 }
@@ -40,18 +72,29 @@ const showServers = async () => {
     const guilds = await getGuilds();
     Object.keys(guilds).forEach(id => {
         if (guilds[id]) {
-            const element = document.getElementById(id);
-            if (element !== null) {
-                const button = document.createElement("button");
-                button.tagName = "button";
-                button.className = "joinButton";
-                button.disabled = true;
-                button.innerHTML = "Joined"
-                element.querySelector("a").replaceWith(button);
-            }
+            setJoined(id);
         }
     })
 };
+// Switch Join button to Joined for server
+const setJoined = id => {
+    element = document.getElementById(id);
+    if (element === null) {
+        return;
+    }
+    // Check if already set as joined
+    a = element.querySelector("a");
+    if (a === null) {
+        return;
+    }
+    const button = document.createElement("button");
+    button.tagName = "button";
+    button.className = "joinButton";
+    button.disabled = true;
+    button.innerHTML = "Joined"
+    element.querySelector("a").replaceWith(button);
+}
+
 // Check for welcomed cookie
 const welcomed = () => document.cookie.split("; ").includes("welcomed=true");
 // Load welcome modal, check if it is necessary
@@ -61,15 +104,7 @@ const loadServers = async () => {
         // in case user pressed Join servers button
         document.querySelector("dialog .welcome").style.display = "none";
     } else {
-        let is_in_participating_server = false;
         const guilds = await getGuilds();
-        const ids = Object.keys(guilds);
-        for (let i = 0; i < ids.length; i++) {
-            if (guilds[ids[i]]) {
-                is_in_participating_server = true;
-                break;
-            }
-        }
         if (!is_in_participating_server) {
             showServers();
         }