From e5e812ff671f085cb584b2e4476ef9f7378e3c72 Mon Sep 17 00:00:00 2001
From: Jonathan Dobson <jon.m.dobson@gmail.com>
Date: Thu, 9 Oct 2025 12:58:36 -0400
Subject: [PATCH] improve time-to-render/availability-checking of BrowserStream
 component (#3667)

---
 .../src/components/BrowserStream.tsx          | 47 ++++++++--
 .../src/routes/workflows/editor/Workspace.tsx | 91 ++++++++-----------
 2 files changed, 77 insertions(+), 61 deletions(-)

diff --git a/skyvern-frontend/src/components/BrowserStream.tsx b/skyvern-frontend/src/components/BrowserStream.tsx
index 9d2a2f39..565c2ae3 100644
--- a/skyvern-frontend/src/components/BrowserStream.tsx
+++ b/skyvern-frontend/src/components/BrowserStream.tsx
@@ -67,8 +67,8 @@ function BrowserStream({
   onClose,
 }: Props) {
   let showStream: boolean = false;
-  let runId: string;
-  let entity: "browserSession" | "task" | "workflow";
+  let runId: string | null;
+  let entity: "browserSession" | "task" | "workflow" | null;
 
   if (browserSessionId) {
     runId = browserSessionId;
@@ -84,7 +84,8 @@ function BrowserStream({
     showStream = statusIsNotFinalized(workflow.run);
     entity = "workflow";
   } else {
-    throw new Error("No browser session id, task or workflow provided");
+    entity = null;
+    runId = null;
   }
 
   useQuery({
@@ -120,6 +121,8 @@ function BrowserStream({
   const [vncDisconnectedTrigger, setVncDisconnectedTrigger] = useState(0);
   const prevVncConnectedRef = useRef<boolean>(false);
   const [isVncConnected, setIsVncConnected] = useState<boolean>(false);
+  const [isCanvasReady, setIsCanvasReady] = useState<boolean>(false);
+  const [isReady, setIsReady] = useState(false);
   const [commandDisconnectedTrigger, setCommandDisconnectedTrigger] =
     useState(0);
   const prevCommandConnectedRef = useRef<boolean>(false);
@@ -131,6 +134,7 @@ function BrowserStream({
     setCanvasContainer(node);
   }, []);
   const rfbRef = useRef<RFB | null>(null);
+  const observerRef = useRef<MutationObserver | null>(null);
   const clientId = useClientIdStore((state) => state.clientId);
   const credentialGetter = useCredentialGetter();
 
@@ -154,6 +158,11 @@ function BrowserStream({
     return `${params}`;
   }, [clientId, credentialGetter]);
 
+  // browser is ready
+  useEffect(() => {
+    setIsReady(isVncConnected && isCanvasReady && hasBrowserSession);
+  }, [hasBrowserSession, isCanvasReady, isVncConnected]);
+
   // effect for vnc disconnects only
   useEffect(() => {
     if (prevVncConnectedRef.current && !isVncConnected) {
@@ -218,31 +227,57 @@ function BrowserStream({
           throw new Error("Canvas element not found");
         }
 
+        observerRef.current = new MutationObserver(() => {
+          const canvasElement = canvasContainer.querySelector("canvas");
+          if (canvasElement) {
+            setIsCanvasReady(true);
+            observerRef.current?.disconnect();
+          }
+        });
+
+        observerRef.current.observe(canvasContainer, {
+          childList: true,
+          subtree: true,
+        });
+
         const rfb = new RFB(canvas, vncUrl);
 
         rfb.scaleViewport = true;
 
         rfbRef.current = rfb;
 
+        const canvasElement = canvasContainer.querySelector("canvas");
+
+        if (canvasElement) {
+          setIsCanvasReady(true);
+          observerRef.current?.disconnect();
+        }
+
         rfb.addEventListener("connect", () => {
           setIsVncConnected(true);
         });
 
         rfb.addEventListener("disconnect", async (/* e: RfbEvent */) => {
           setIsVncConnected(false);
+          setIsCanvasReady(false);
         });
 
-        // setIsVncConnected(true); // be optimistic
+        setIsVncConnected(true); // be optimistic
       }
 
       setupVnc();
 
       return () => {
+        if (observerRef.current) {
+          observerRef.current.disconnect();
+          observerRef.current = null;
+        }
         if (rfbRef.current) {
           rfbRef.current.disconnect();
           rfbRef.current = null;
         }
         setIsVncConnected(false);
+        setIsCanvasReady(false);
       };
     },
     // cannot include isVncConnected in deps as it will cause infinite loop
@@ -402,7 +437,7 @@ function BrowserStream({
       )}
       ref={setCanvasContainerRef}
     >
-      {isVncConnected && hasBrowserSession && (
+      {isReady && (
         <div className="overlay z-10 flex items-center justify-center overflow-hidden">
           {showControlButtons && (
             <div className="control-buttons pointer-events-none relative flex h-full w-full items-center justify-center">
@@ -437,7 +472,7 @@ function BrowserStream({
           )}
         </div>
       )}
-      {!isVncConnected && (
+      {!isReady && (
         <div className="absolute left-0 top-1/2 flex aspect-video max-h-full w-full -translate-y-1/2 flex-col items-center justify-center gap-2 rounded-md border border-slate-800 text-sm text-slate-400">
           {browserSessionId && !hasBrowserSession ? (
             <div>This live browser session is no longer streaming.</div>
diff --git a/skyvern-frontend/src/routes/workflows/editor/Workspace.tsx b/skyvern-frontend/src/routes/workflows/editor/Workspace.tsx
index d431a93a..b5f5288b 100644
--- a/skyvern-frontend/src/routes/workflows/editor/Workspace.tsx
+++ b/skyvern-frontend/src/routes/workflows/editor/Workspace.tsx
@@ -706,16 +706,8 @@ function Workspace({
     version2: WorkflowVersion,
     mode: "visual" | "json" = "visual",
   ) => {
-    console.log(
-      `${mode === "visual" ? "Visual" : "JSON"} comparison between versions:`,
-      version1.version,
-      "and",
-      version2.version,
-    );
-
     // Implement visual drawer comparison
     if (mode === "visual") {
-      console.log("Opening visual comparison panel...");
       // Keep history panel active but add comparison data
       setWorkflowPanelState({
         active: true,
@@ -731,15 +723,13 @@ function Workspace({
     // TODO: Implement JSON diff comparison
     if (mode === "json") {
       // This will open a JSON diff view
-      console.log("Opening JSON diff view...");
+      console.warn("[Not Implemented] opening JSON diff view...");
       // Future: setJsonDiffOpen(true);
       // Future: setJsonDiffVersions({ version1, version2 });
     }
   };
 
   const handleSelectState = (selectedVersion: WorkflowVersion) => {
-    console.log("Loading version into main editor:", selectedVersion.version);
-
     // Close panels
     setWorkflowPanelState({
       active: false,
@@ -1269,51 +1259,42 @@ function Workspace({
               {/* browser & timeline */}
               <div className="flex h-[calc(100%_-_8rem)] w-full gap-6">
                 {/* VNC browser */}
-                {!activeDebugSession ||
-                  (activeDebugSession.vnc_streaming_supported && (
-                    <div className="skyvern-vnc-browser flex h-full w-[calc(100%_-_6rem)] flex-1 flex-col items-center justify-center">
-                      <div key={reloadKey} className="w-full flex-1">
-                        {activeDebugSession &&
-                        activeDebugSession.browser_session_id &&
-                        !cycleBrowser.isPending ? (
-                          <BrowserStream
-                            interactive={true}
-                            browserSessionId={
-                              activeDebugSession.browser_session_id
-                            }
-                            showControlButtons={true}
-                            resizeTrigger={windowResizeTrigger}
-                          />
-                        ) : (
-                          <div className="flex aspect-video w-full flex-col items-center justify-center gap-2 rounded-md border border-slate-800 pb-2 pt-4 text-sm text-slate-400">
-                            Connecting to your browser...
-                            <AnimatedWave text=".‧₊˚ ⋅ ✨★ ‧₊˚ ⋅" />
-                          </div>
-                        )}
-                      </div>
-                      <footer className="flex h-[2rem] w-full items-center justify-start gap-4">
-                        <div className="flex items-center gap-2">
-                          <GlobeIcon /> Live Browser
-                        </div>
-                        {showBreakoutButton && (
-                          <BreakoutButton onClick={() => breakout()} />
-                        )}
-                        <div
-                          className={cn("ml-auto flex items-center gap-2", {
-                            "mr-16": !blockLabel,
-                          })}
-                        >
-                          {showPowerButton && (
-                            <PowerButton onClick={() => cycle()} />
-                          )}
-                          <ReloadButton
-                            isReloading={isReloading}
-                            onClick={() => reload()}
-                          />
-                        </div>
-                      </footer>
+                {(!activeDebugSession ||
+                  activeDebugSession.vnc_streaming_supported) && (
+                  <div className="skyvern-vnc-browser flex h-full w-[calc(100%_-_6rem)] flex-1 flex-col items-center justify-center">
+                    <div key={reloadKey} className="w-full flex-1">
+                      <BrowserStream
+                        interactive={true}
+                        browserSessionId={
+                          activeDebugSession?.browser_session_id
+                        }
+                        showControlButtons={true}
+                        resizeTrigger={windowResizeTrigger}
+                      />
                     </div>
-                  ))}
+                    <footer className="flex h-[2rem] w-full items-center justify-start gap-4">
+                      <div className="flex items-center gap-2">
+                        <GlobeIcon /> Live Browser
+                      </div>
+                      {showBreakoutButton && (
+                        <BreakoutButton onClick={() => breakout()} />
+                      )}
+                      <div
+                        className={cn("ml-auto flex items-center gap-2", {
+                          "mr-16": !blockLabel,
+                        })}
+                      >
+                        {showPowerButton && (
+                          <PowerButton onClick={() => cycle()} />
+                        )}
+                        <ReloadButton
+                          isReloading={isReloading}
+                          onClick={() => reload()}
+                        />
+                      </div>
+                    </footer>
+                  </div>
+                )}
 
                 {/* Screenshot browser} */}
                 {activeDebugSession &&