fix: automatically reconnect after losing a WebSocket connection

src/hooks/mod.rs

@@ -1,6 +1,6 @@
 use dioxus::{
     CapturedError,
-    fullstack::{Loader, Loading, WebSocketOptions, use_websocket},
+    fullstack::{Loader, Loading, WebSocketOptions},
     prelude::*,
 };
 use serde::{Serialize, de::DeserializeOwned};
@@ -13,6 +13,29 @@ use crate::{
     },
 };
 
+fn use_on_document_become_visible(mut callback: impl FnMut() + 'static) {
+    let callback = use_callback(move |_| callback());
+    use_effect(move || {
+        spawn(async move {
+            let mut eval = document::eval(
+                r#"
+                document.addEventListener("visibilitychange", () => {
+                if (!document.hidden) {
+                    dioxus.send(0);
+                }
+                });
+                "#,
+            );
+            loop {
+                eval.recv::<u8>()
+                    .await
+                    .expect("The JS code returned a value not parsable to `u8`.");
+                callback.call(());
+            }
+        });
+    });
+}
+
 #[allow(clippy::result_large_err)]
 fn sort_loader_result<T: Ord + Clone>(
     result: Result<Loader<Vec<T>>, Loading>,
@@ -34,18 +57,38 @@ where
     E: Into<CapturedError> + 'static,
 {
     let mut refresh_tick = use_signal(|| 0u64);
+    let mut websocket_reset_tick = use_signal(|| 0u64);
 
     let loader = use_loader(move || {
         let _ = refresh_tick(); // Read => dependency.
         future()
     });
 
-    let mut socket = use_websocket(|| subscribe_to_updates(WebSocketOptions::default()));
-    use_future(move || async move {
+    use_effect(move || {
+        let initial_websocket_reset_tick = websocket_reset_tick();
+        spawn(async move {
+            let Ok(socket) =
+                subscribe_to_updates(WebSocketOptions::new().with_automatic_reconnect()).await
+            else {
+                return;
+            };
             while socket.recv().await.is_ok() {
+                if websocket_reset_tick() != initial_websocket_reset_tick {
+                    // A new WebSocket has been created (a new task spawned), cleaning this one up.
+                    break;
+                }
                 refresh_tick += 1;
             }
         });
+    });
+
+    /* So that when the device goes to sleep or suspends the app, the WebSocket gets recreated on
+    waking up. It is important to do this only on becoming visible (document.hidden == false),
+    because becoming hidden is the part when network may not work and thus cause errors. */
+    use_on_document_become_visible(move || {
+        websocket_reset_tick += 1;
+        refresh_tick += 1;
+    });
 
     loader
 }