add websocket stream for statistics

src/webapi.rs

@@ -1,10 +1,10 @@
-use std::{net::SocketAddr, process::exit, sync::Arc};
+use std::{net::SocketAddr, process::exit, sync::Arc, time::Duration};
 
 use axum::{
-    extract::{ConnectInfo, Query, State},
+    extract::{ws::Message, ConnectInfo, Query, State, WebSocketUpgrade},
     http::{self, HeaderMap, HeaderValue},
-    response::IntoResponse,
-    routing::any,
+    response::{IntoResponse, Response},
+    routing::get,
     Router,
 };
 use axum_extra::TypedHeader;
@@ -12,14 +12,14 @@ use axum_streams::StreamBodyAs;
 use futures::{never::Never, stream::repeat_with, Stream};
 use rust_embed::RustEmbed;
 use serde::Deserialize;
-use tokio::net::TcpListener;
+use tokio::{net::TcpListener, time::interval};
 use tower_http::trace::{DefaultMakeSpan, TraceLayer};
 
 use crate::{
     config::{WEB_HOST, WEB_UPDATE_INTERVAL},
     grid,
     stream::Multipart,
-    AsyncResult,
+    AsyncResult, CLIENTS, COUNTER,
 };
 
 #[derive(RustEmbed, Clone)]
@@ -38,7 +38,8 @@ pub async fn serve(ctx: WebApiContext) -> AsyncResult<Never> {
         Some("index.html".to_string()),
     );
     let app = Router::new()
-        .route("/imgstream", any(image_stream))
+        .route("/imgstream", get(image_stream))
+        .route("/stats", get(stats_stream))
         .nest_service("/", assets)
         .with_state(ctx)
         // logging middleware
@@ -85,6 +86,24 @@ fn make_image_stream(
     .throttle(WEB_UPDATE_INTERVAL)
 }
 
+fn make_stats() -> Message {
+    let pixels: u64 = COUNTER.load(std::sync::atomic::Ordering::Relaxed);
+    let clients: u64 = CLIENTS.load(std::sync::atomic::Ordering::Relaxed);
+    format!("{{\"c\":{}, \"p\":{}}}", clients, pixels).into()
+}
+
+async fn stats_stream(ws: WebSocketUpgrade) -> Response {
+    ws.on_upgrade(|mut c| async move {
+        let mut interval = interval(Duration::from_millis(100));
+        loop {
+            interval.tick().await;
+            if let Err(e) = c.send(make_stats()).await {
+                tracing::warn!("websocket disconnected with {e:?}")
+            }
+        }
+    })
+}
+
 async fn image_stream(
     user_agent: Option<TypedHeader<headers::UserAgent>>,
     ConnectInfo(addr): ConnectInfo<SocketAddr>,