Add ping/pong keep-alive to prevent service worker termination

extension/manifest.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "Playwriter MCP",
-  "version": "0.0.61",
+  "version": "0.0.64",
   "description": "Automate your Browser using Cursor, Claude, VS Code. More capable and context efficient than Playwright MCP.",
   "permissions": ["debugger", "tabGroups", "contextMenus", "tabs"],
   "host_permissions": ["<all_urls>"],

extension/package.json

@@ -1,6 +1,6 @@
 {
     "name": "mcp-extension",
-    "version": "0.0.61",
+    "version": "0.0.64",
     "description": "Playwright MCP Browser Extension",
     "private": true,
     "repository": {

playwriter/src/cdp-relay.ts

@@ -41,6 +41,23 @@ export async function startPlayWriterCDPRelayServer({ port = 19988, host = '127.
     reject: (error: Error) => void
   }>()
   let extensionMessageId = 0
+  let extensionPingInterval: ReturnType<typeof setInterval> | null = null
+
+  function startExtensionPing() {
+    if (extensionPingInterval) {
+      clearInterval(extensionPingInterval)
+    }
+    extensionPingInterval = setInterval(() => {
+      extensionWs?.send(JSON.stringify({ method: 'ping' }))
+    }, 5000)
+  }
+
+  function stopExtensionPing() {
+    if (extensionPingInterval) {
+      clearInterval(extensionPingInterval)
+      extensionPingInterval = null
+    }
+  }
 
   function logCdpMessage({
     direction,
@@ -504,6 +521,7 @@ export async function startPlayWriterCDPRelayServer({ port = 19988, host = '127.
         }
 
         extensionWs = ws
+        startExtensionPing()
         logger?.log('Extension connected with clean state')
       },
 
@@ -517,7 +535,7 @@ export async function startPlayWriterCDPRelayServer({ port = 19988, host = '127.
           return
         }
 
-        if ('id' in message) {
+        if (message.id !== undefined) {
           const pending = extensionPendingRequests.get(message.id)
           if (!pending) {
             logger?.log('Unexpected response with id:', message.id)
@@ -531,6 +549,8 @@ export async function startPlayWriterCDPRelayServer({ port = 19988, host = '127.
           } else {
             pending.resolve(message.result)
           }
+        } else if (message.method === 'pong') {
+          // Keep-alive response, nothing to do
         } else if (message.method === 'log') {
           const { level, args } = message.params
           const logFn = (logger as any)?.[level] || logger?.log
@@ -681,7 +701,8 @@ export async function startPlayWriterCDPRelayServer({ port = 19988, host = '127.
       },
 
       onClose(event, ws) {
-        logger?.log('Extension disconnected')
+        logger?.log(`Extension disconnected: code=${event.code} reason=${event.reason || 'none'}`)
+        stopExtensionPing()
 
         // If this is an old connection closing after we've already established a new one,
         // don't clear the global state

playwriter/src/protocol.ts

@@ -19,6 +19,7 @@ export type ExtensionCommandMessage = ForwardCDPCommand
 
 export type ExtensionResponseMessage = {
   id: number
+  method?: undefined
   result?: any
   error?: string
 }
@@ -30,6 +31,7 @@ export type ExtensionResponseMessage = {
 export type ExtensionEventMessage =
   {
     [K in keyof ProtocolMapping.Events]: {
+      id?: undefined
       method: 'forwardCDPEvent'
       params: {
         method: CDPEventFor<K>['method']
@@ -40,6 +42,7 @@ export type ExtensionEventMessage =
   }[keyof ProtocolMapping.Events]
 
 export type ExtensionLogMessage = {
+  id?: undefined
   method: 'log'
   params: {
     level: 'log' | 'debug' | 'info' | 'warn' | 'error'
@@ -47,4 +50,14 @@ export type ExtensionLogMessage = {
   }
 }
 
-export type ExtensionMessage = ExtensionResponseMessage | ExtensionEventMessage | ExtensionLogMessage
+export type ExtensionPongMessage = {
+  id?: undefined
+  method: 'pong'
+}
+
+export type ServerPingMessage = {
+  method: 'ping'
+  id?: undefined
+}
+
+export type ExtensionMessage = ExtensionResponseMessage | ExtensionEventMessage | ExtensionLogMessage | ExtensionPongMessage