try to localize the event queue and processing flag to the socket

reflex/.templates/web/utils/state.js

@@ -35,11 +35,6 @@ const cookies = new Cookies();
 // Dictionary holding component references.
 export const refs = {};
 
-// Flag ensures that only one event is processing on the backend concurrently.
-let event_processing = false;
-// Array holding pending events to be processed.
-const event_queue = [];
-
 /**
  * Generate a UUID (Used for session tokens).
  * Taken from: https://stackoverflow.com/questions/105034/how-do-i-create-a-guid-uuid
@@ -108,13 +103,16 @@ export const getBackendURL = (url_str) => {
 /**
  * Determine if any event in the event queue is stateful.
  *
+ * @param socket The socket object to check for stateful events.
  * @returns True if there's any event that requires state and False if none of them do.
  */
-export const isStateful = () => {
-  if (event_queue.length === 0) {
+export const isStateful = (socket) => {
+  if (socket.event_queue.length === 0) {
     return false;
   }
-  return event_queue.some((event) => event.name.startsWith("reflex___state"));
+  return socket.event_queue.some((event) =>
+    event.name.startsWith("reflex___state")
+  );
 };
 
 /**
@@ -295,10 +293,7 @@ export const applyEvent = async (event, socket) => {
 
   // Send the event to the server.
   if (socket) {
-    socket.emit(
-      "event",
-      event,
-    );
+    socket.emit("event", event);
     return true;
   }
 
@@ -339,7 +334,7 @@ export const applyRestEvent = async (event, socket) => {
  * @param socket The socket object to send the event on.
  */
 export const queueEvents = async (events, socket) => {
-  event_queue.push(...events);
+  socket.current.event_queue.push(...events);
   await processEvent(socket.current);
 };
 
@@ -349,20 +344,20 @@ export const queueEvents = async (events, socket) => {
  */
 export const processEvent = async (socket) => {
   // Only proceed if the socket is up and no event in the queue uses state, otherwise we throw the event into the void
-  if (!socket && isStateful()) {
+  if (!socket && isStateful(socket)) {
     return;
   }
 
   // Only proceed if we're not already processing an event.
-  if (event_queue.length === 0 || event_processing) {
+  if (socket.event_queue.length === 0 || socket.event_processing) {
     return;
   }
 
   // Set processing to true to block other events from being processed.
-  event_processing = true;
+  socket.event_processing = true;
 
   // Apply the next event in the queue.
-  const event = event_queue.shift();
+  const event = socket.event_queue.shift();
 
   let eventSent = false;
   // Process events with handlers via REST and all others via websockets.
@@ -373,7 +368,7 @@ export const processEvent = async (socket) => {
   }
   // If no event was sent, set processing to false.
   if (!eventSent) {
-    event_processing = false;
+    socket.event_processing = false;
     // recursively call processEvent to drain the queue, since there is
     // no state update to trigger the useEffect event loop.
     await processEvent(socket);
@@ -409,8 +404,12 @@ export const connect = async (
     transports: transports,
     autoUnref: false,
   });
+  // Array holding pending events to be processed.
+  socket.current.event_queue = [];
+  // Flag ensures that only one event is processing on the backend concurrently.
+  socket.current.event_processing = false;
   // Ensure undefined fields in events are sent as null instead of removed
-  socket.current.io.encoder.replacer = (k, v) => (v === undefined ? null : v)
+  socket.current.io.encoder.replacer = (k, v) => (v === undefined ? null : v);
 
   function checkVisibility() {
     if (document.visibilityState === "visible") {
@@ -443,9 +442,7 @@ export const connect = async (
 
   // When the socket disconnects reset the event_processing flag
   socket.current.on("disconnect", () => {
-    event_processing = false;
-    socket.current.io.skipReconnect = true;
-    socket.current = null;
+    socket.current.event_processing = false;
     window.removeEventListener("pagehide", pagehideHandler);
     document.removeEventListener("visibilitychange", checkVisibility);
   });
@@ -456,16 +453,15 @@ export const connect = async (
       dispatch[substate](update.delta[substate]);
     }
     applyClientStorageDelta(client_storage, update.delta);
-    event_processing = !update.final;
+    socket.current.event_processing = !update.final;
     if (update.events) {
       queueEvents(update.events, socket);
     }
   });
   socket.current.on("reload", async (event) => {
-    event_processing = false;
+    socket.current.event_processing = false;
     queueEvents([...initialEvents(), event], socket);
   });
-
 };
 
 /**
@@ -491,7 +487,7 @@ export const uploadFiles = async (
     return false;
   }
 
-  const upload_ref_name = `__upload_controllers_${upload_id}`
+  const upload_ref_name = `__upload_controllers_${upload_id}`;
 
   if (refs[upload_ref_name]) {
     console.log("Upload already in progress for ", upload_id);
@@ -755,9 +751,32 @@ export const useEventLoop = (
     }
   };
 
-  const sentHydrate = useRef(false); // Avoid double-hydrate due to React strict-mode
   useEffect(() => {
-    if (router.isReady && !sentHydrate.current) {
+    // Initialize the websocket connection.
+    if (!socket.current) {
+      console.log("Creating websocket connection");
+      connect(
+        socket,
+        dispatch,
+        ["websocket"],
+        setConnectErrors,
+        client_storage
+      );
+      return () => {
+        if (socket.current) {
+          console.log("Discarded socket disconnected");
+          socket.current.io.skipReconnect = true;
+          socket.current.disconnect();
+          socket.current = null;
+        }
+      };
+    }
+  }, []);
+
+  //const sentHydrate = useRef(false); // Avoid double-hydrate due to React strict-mode
+  useEffect(() => {
+    console.log("Maybe initial hydrate", router.isReady, !!socket.current);
+    if (router.isReady && socket.current) {
       const events = initial_events();
       addEvents(
         events.map((e) => ({
@@ -769,9 +788,9 @@ export const useEventLoop = (
           }))(router),
         }))
       );
-      sentHydrate.current = true;
+      //sentHydrate.current = true;
     }
-  }, [router.isReady]);
+  }, [router.isReady, socket.current]);
 
   // Handle frontend errors and send them to the backend via websocket.
   useEffect(() => {
@@ -803,34 +822,23 @@ export const useEventLoop = (
   }, []);
 
   // Main event loop.
-  useEffect(() => {
-    // Skip if the router is not ready.
-    if (!router.isReady) {
-      return;
-    }
-    // only use websockets if state is present
-    if (Object.keys(initialState).length > 1) {
-      // Initialize the websocket connection.
-      if (!socket.current) {
-        connect(
-          socket,
-          dispatch,
-          ["websocket"],
-          setConnectErrors,
-          client_storage
-        );
-      }
-      (async () => {
-        // Process all outstanding events.
-        while (event_queue.length > 0 && !event_processing) {
-          await processEvent(socket.current);
-        }
-      })();
-    }
-  });
+  // useEffect(() => {
+  //   // Skip if the router is not ready.
+  //   if (!router.isReady) {
+  //     return;
+  //   }
+  //   (async () => {
+  //     // Process all outstanding events.
+  //     console.log("Process outstanding events");
+  //     while (socket.current.event_queue.length > 0 && !socket.current.event_processing) {
+  //       await processEvent(socket.current);
+  //     }
+  //   })();
+  // });
 
   // localStorage event handling
   useEffect(() => {
+    console.log("Setting up localStorage event listener");
     const storage_to_state_map = {};
 
     if (client_storage.local_storage && typeof window !== "undefined") {
@@ -858,10 +866,11 @@ export const useEventLoop = (
 
     window.addEventListener("storage", handleStorage);
     return () => window.removeEventListener("storage", handleStorage);
-  });
+  }, []);
 
   // Route after the initial page hydration.
   useEffect(() => {
+    console.log("Setting up route change listeners");
     const change_start = () => {
       const main_state_dispatch = dispatch["reflex___state____state"];
       if (main_state_dispatch !== undefined) {