feat: add live listener count

.gitignore

@@ -4,8 +4,7 @@
 ### Linux ###
 *~
 
-# temporary files which can be created if a process still has a handle open of a deleted file
-.fuse_hidden*
+# temporary files which can be created if a process still has a handle open of a deleted file .fuse_hidden*
 
 # KDE directory preferences
 .directory
@@ -249,3 +248,13 @@ $RECYCLE.BIN/
 
 # End of https://www.toptal.com/developers/gitignore/api/python,windows,macos,linux
 
+0.mp3
+1.mp3
+2.mp3
+3.mp3
+4.mp3
+5.mp3
+6.mp3
+7.mp3
+8.mp3
+9.mp3

server.py

@@ -3,10 +3,11 @@
 
 import websocket
 from contextlib import asynccontextmanager
-from fastapi import FastAPI
+from fastapi import FastAPI, WebSocket, WebSocketDisconnect
 from fastapi.responses import FileResponse
 from fastapi.staticfiles import StaticFiles
 from logger import log_info, log_warn
+from websocket_connection_manager import WebSocketConnectionManager
 
 # the index of the current audio track from 0 to 9
 current_index = -1
@@ -15,6 +16,8 @@
 # websocket connection to the inference server
 ws = None
 ws_url = ""
+ws_connection_manager = WebSocketConnectionManager()
+active_listeners = set()
 
 
 @asynccontextmanager
@@ -83,7 +86,6 @@ def advance():
         current_index = 0
     else:
         current_index = current_index + 1
-
     threading.Thread(target=generate_new_audio).start()
 
     t = threading.Timer(60, advance)
@@ -98,4 +100,35 @@ def get_current_audio():
     return FileResponse(f"{current_index}.mp3")
 
 
+@app.websocket("/ws")
+async def ws_endpoint(ws: WebSocket):
+    await ws_connection_manager.connect(ws)
+
+    addr = ""
+    if ws.client:
+        addr, _ = ws.client
+    else:
+        await ws.close()
+        ws_connection_manager.disconnect(ws)
+
+    try:
+        while True:
+            msg = await ws.receive_text()
+
+            if msg == "playing":
+                active_listeners.add(addr)
+                await ws_connection_manager.broadcast(f"{len(active_listeners)}")
+            elif msg == "paused":
+                active_listeners.remove(addr)
+                await ws_connection_manager.broadcast(f"{len(active_listeners)}")
+
+    except WebSocketDisconnect:
+        if ws.client:
+            addr, _ = ws.client
+            active_listeners.discard(addr)
+        ws_connection_manager.disconnect(ws)
+
+        await ws_connection_manager.broadcast(f"{len(active_listeners)}")
+
+
 app.mount("/", StaticFiles(directory="web", html=True), name="web")

web/index.html

@@ -27,11 +27,16 @@ <h2>infinite lo-fi music in the background</h2>
 				<div class="button-container">
 					<button id="play-btn" class="button">play</button>
 				</div>
-				<div class="volume-slider-container">
-					<output id="current-volume-label" for="volume-slider">100%</output>
-					<input id="volume-slider" type="range" min="0" max="100" step="1">
+
+				<div class="status-bar">
+					<p id="listener-count">0 person tuned in</p>
+					<div class="volume-slider-container">
+						<output id="current-volume-label" for="volume-slider">100%</output>
+						<input id="volume-slider" type="range" min="0" max="100" step="1" />
+					</div>
 				</div>
 			</main>
+
 			<img class="cat" src="./images/cat-0.png">
 			<img class="eeping-cat" src="./images/eeping-cat.png">
 		</div>

web/script.js

@@ -1,32 +1,40 @@
+const CROSSFADE_DURATION_MS = 5000;
+const CROSSFADE_INTERVAL_MS = 20;
+const AUDIO_DURATION_MS = 60000;
+
 const playBtn = document.getElementById("play-btn");
 const catImg = document.getElementsByClassName("cat")[0];
 const volumeSlider = document.getElementById("volume-slider");
 const currentVolumeLabel = document.getElementById("current-volume-label");
 const clickAudio = document.getElementById("click-audio");
 const clickReleaseAudio = document.getElementById("click-release-audio");
 const meowAudio = document.getElementById("meow-audio");
-
-const CROSSFADE_DURATION_MS = 5000;
-const CROSSFADE_INTERVAL_MS = 20;
-const AUDIO_DURATION_MS = 60000;
+const listenerCountLabel = document.getElementById("listener-count");
 
 let isPlaying = false;
 let isFading = false;
 let currentAudio;
 let maxVolume = 100;
 let currentVolume = 0;
+let ws = connectToWebSocket();
 
 function playAudio() {
 	// add a random query parameter at the end to prevent browser caching
 	currentAudio = new Audio(`./current.mp3?t=${Date.now()}`);
 	currentAudio.onplay = () => {
 		isPlaying = true;
 		playBtn.innerText = "pause";
+		if (ws) {
+			ws.send("playing");
+		}
 	};
 	currentAudio.onpause = () => {
 		isPlaying = false;
 		currentVolume = 0;
 		playBtn.innerText = "play";
+		if (ws) {
+			ws.send("paused");
+		}
 	};
 	currentAudio.onended = () => {
 		currentVolume = 0;
@@ -122,6 +130,31 @@ function enableSpaceBarControl() {
 	});
 }
 
+function connectToWebSocket() {
+	const ws = new WebSocket(`ws://${location.host}/ws`);
+	ws.onmessage = (event) => {
+		console.log(event.data);
+
+		if (typeof event.data !== "string") {
+			return;
+		}
+
+		const listenerCountStr = event.data;
+		const listenerCount = Number.parseInt(listenerCountStr);
+		if (Number.isNaN(listenerCount)) {
+			return;
+		}
+
+		if (listenerCount <= 1) {
+			listenerCountLabel.innerText = `${listenerCount} person tuned in`;
+		} else {
+			listenerCountLabel.innerText = `${listenerCount} ppl tuned in`;
+		}
+	};
+
+	return ws;
+}
+
 playBtn.onmousedown = () => {
 	clickAudio.play();
 	document.addEventListener(
@@ -157,7 +190,15 @@ volumeSlider.oninput = () => {
 	clickReleaseAudio.volume = volumeSlider.value / 100;
 	meowAudio.volume = volumeSlider.value / 100;
 };
-
 volumeSlider.value = 100;
+
+window.addEventListener("offline", () => {
+	ws = null;
+});
+
+window.addEventListener("online", () => {
+	ws = connectToWebSocket();
+});
+
 animateCat();
 enableSpaceBarControl();

web/style.css

@@ -108,6 +108,25 @@ a {
   border-radius: 2px;
 }
 
+.status-bar {
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  z-index: -10;
+  display: flex;
+  flex-direction: row;
+  justify-content: space-between;
+  padding: 2rem;
+  z-index: 0;
+  color: var(--text);
+}
+
+.status-bar > #listener-count {
+  margin: 0;
+  opacity: 0.8;
+}
+
 .header {
   font-weight: 800;
   margin-bottom: 1rem;
@@ -152,11 +171,6 @@ a {
 }
 
 .volume-slider-container {
-  position: absolute;
-  top: 0;
-  right: 0;
-  padding: 0.5rem 1rem;
-  margin: 1rem;
   display: flex;
   justify-content: start;
   align-items: center;

websocket_connection_manager.py

@@ -0,0 +1,19 @@
+import asyncio
+from fastapi import WebSocket
+
+
+class WebSocketConnectionManager:
+    def __init__(self) -> None:
+        self.__active_connections: list[WebSocket] = []
+
+    async def connect(self, ws: WebSocket):
+        await ws.accept()
+        self.__active_connections.append(ws)
+
+    def disconnect(self, ws: WebSocket):
+        self.__active_connections.remove(ws)
+
+    async def broadcast(self, msg: str):
+        await asyncio.gather(
+            *[conn.send_text(msg) for conn in self.__active_connections]
+        )