Updated to reuse session id if available

execution.py

@@ -55,6 +55,7 @@ def recursive_execute(server, prompt, outputs, current_item, extra_data={}):
 
     input_data_all = get_input_data(inputs, class_def, outputs, prompt, extra_data)
     if server.client_id is not None:
+        server.last_node_id = unique_id
         server.send_sync("executing", { "node": unique_id }, server.client_id)
     obj = class_def()
 
@@ -188,6 +189,7 @@ class PromptExecutor:
                 for x in executed:
                     self.old_prompt[x] = copy.deepcopy(prompt[x])
             finally:
+                self.server.last_node_id = None
                 if self.server.client_id is not None:
                     self.server.send_sync("executing", { "node": None }, self.server.client_id)
 

server.py

@@ -32,21 +32,34 @@ class PromptServer():
         self.web_root = os.path.join(os.path.dirname(
             os.path.realpath(__file__)), "web")
         routes = web.RouteTableDef()
+        self.last_node_id = None
+        self.client_id = None
 
         @routes.get('/ws')
         async def websocket_handler(request):
             ws = web.WebSocketResponse()
             await ws.prepare(request)
-            sid = uuid.uuid4().hex
+            sid = request.rel_url.query.get('clientId', '')
+            if sid:
+                # Reusing existing session, remove old
+                self.sockets.pop(sid, None)
+            else:
+                sid = uuid.uuid4().hex      
+
             self.sockets[sid] = ws
+
             try:
                 # Send initial state to the new client
                 await self.send("status", { "status": self.get_queue_info(), 'sid': sid }, sid)
+                # On reconnect if we are the currently executing client send the current node
+                if self.client_id == sid and self.last_node_id is not None:
+                    await self.send("executing", { "node": self.last_node_id }, sid)
+                    
                 async for msg in ws:
                     if msg.type == aiohttp.WSMsgType.ERROR:
                         print('ws connection closed with exception %s' % ws.exception())
             finally:
-                self.sockets.pop(sid)
+                self.sockets.pop(sid, None)
             return ws
 
         @routes.get("/")

web/scripts/api.js

@@ -28,7 +28,13 @@ class ComfyApi extends EventTarget {
 		}
 
 		let opened = false;
-		this.socket = new WebSocket(`ws${window.location.protocol === "https:" ? "s" : ""}://${location.host}/ws`);
+		let existingSession = sessionStorage["Comfy.SessionId"] || "";
+		if (existingSession) {
+			existingSession = "?clientId=" + existingSession;
+		}
+		this.socket = new WebSocket(
+			`ws${window.location.protocol === "https:" ? "s" : ""}://${location.host}/ws${existingSession}`
+		);
 
 		this.socket.addEventListener("open", () => {
 			opened = true;
@@ -62,6 +68,7 @@ class ComfyApi extends EventTarget {
 					case "status":
 						if (msg.data.sid) {
 							this.clientId = msg.data.sid;
+							sessionStorage["Comfy.SessionId"] = this.clientId;
 						}
 						this.dispatchEvent(new CustomEvent("status", { detail: msg.data.status }));
 						break;