From 8d4ef9858cecd56870c06082bf7aed9ab01958c0 Mon Sep 17 00:00:00 2001
From: Alexey Pelykh <alexey.pelykh@gmail.com>
Date: Sat, 28 May 2022 16:03:37 +0200
Subject: [PATCH] Detect disconnected session (fix #2)

---
 package-lock.json                                  |  5 ++++-
 src/PuppeteerCaptureBase.ts                        | 14 ++++++++++++++
 ...PuppeteerCaptureViaHeadlessExperimental.test.ts | 13 +++++++++++++
 src/PuppeteerCaptureViaHeadlessExperimental.ts     |  2 +-
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 2f3a233..f724b49 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,6 @@
       "version": "0.0.0",
       "license": "MIT",
       "dependencies": {
-        "@ffmpeg-installer/ffmpeg": "^1.1.0",
         "async-mutex": "^0.3.2",
         "fluent-ffmpeg": "^2.1.2",
         "which": "^2.0.2"
@@ -26,6 +25,10 @@
         "ts-standard": "^11.0.0",
         "typescript": "^4.6.4"
       },
+      "engines": {
+        "node": ">=14",
+        "npm": ">=7"
+      },
       "optionalDependencies": {
         "@ffmpeg-installer/ffmpeg": "^1.1.0"
       },
diff --git a/src/PuppeteerCaptureBase.ts b/src/PuppeteerCaptureBase.ts
index a5aa1d8..0a3489d 100644
--- a/src/PuppeteerCaptureBase.ts
+++ b/src/PuppeteerCaptureBase.ts
@@ -28,6 +28,7 @@ export abstract class PuppeteerCaptureBase extends EventEmitter implements Puppe
   protected readonly _frameInterval: number
   protected readonly _captureFrame: () => void
   protected readonly _onPageClose: () => void
+  protected readonly _onSessionDisconnected: () => void
   protected readonly _startStopMutex: Mutex
   protected _target: string | Writable | null
   protected _session: puppeteer.CDPSession | null
@@ -62,6 +63,7 @@ export abstract class PuppeteerCaptureBase extends EventEmitter implements Puppe
     this._frameInterval = 1000.0 / this._options.fps
     this._captureFrame = this.captureFrame.bind(this)
     this._onPageClose = this.onPageClose.bind(this)
+    this._onSessionDisconnected = this.onSessionDisconnected.bind(this)
     this._startStopMutex = new Mutex()
     this._target = null
     this._session = null
@@ -159,6 +161,7 @@ export abstract class PuppeteerCaptureBase extends EventEmitter implements Puppe
     }
 
     const session = await this._page.target().createCDPSession()
+    session.on('CDPSession.Disconnected', this._onSessionDisconnected)
     await this.configureSession(session)
 
     this._target = target
@@ -284,6 +287,10 @@ export abstract class PuppeteerCaptureBase extends EventEmitter implements Puppe
 
     if (this._session != null) {
       await this.deconfigureSession(this._session)
+      this._session.off('CDPSession.Disconnected', this._onSessionDisconnected)
+      if (this._session.connection() != null) {
+        await this._session.detach()
+      }
       this._session = null
     }
 
@@ -370,6 +377,13 @@ export abstract class PuppeteerCaptureBase extends EventEmitter implements Puppe
       .catch(() => { })
   }
 
+  protected onSessionDisconnected (): void {
+    this._error = new Error('Session was disconnected')
+    this._startStopMutex.runExclusive(async () => await this._stop())
+      .then(() => { })
+      .catch(() => { })
+  }
+
   private static async findFfmpeg (): Promise<string> {
     if (process.env.FFMPEG != null) {
       return process.env.FFMPEG
diff --git a/src/PuppeteerCaptureViaHeadlessExperimental.test.ts b/src/PuppeteerCaptureViaHeadlessExperimental.test.ts
index 3a5b69d..263eae5 100644
--- a/src/PuppeteerCaptureViaHeadlessExperimental.test.ts
+++ b/src/PuppeteerCaptureViaHeadlessExperimental.test.ts
@@ -116,3 +116,16 @@ test('that capture stops gracefully on page close', async () => {
     await capture.stop()
   }).rejects.toThrow('Page was closed')
 })
+
+test('that capture stops gracefully on session connection drop', async () => {
+  browser = await launch({ args: PUPPETEER_LAUNCH_ARGS })
+  const page = await browser.newPage()
+  const capture = new PuppeteerCaptureViaHeadlessExperimental(page)
+  const stream = new PassThrough()
+  await page.goto('https://google.com')
+  await capture.start(stream)
+  capture['_session']!.emit('CDPSession.Disconnected') // eslint-disable-line @typescript-eslint/no-non-null-assertion, @typescript-eslint/dot-notation
+  await expect(async () => {
+    await capture.stop()
+  }).rejects.toThrow('Session was disconnected')
+})
diff --git a/src/PuppeteerCaptureViaHeadlessExperimental.ts b/src/PuppeteerCaptureViaHeadlessExperimental.ts
index ca2836c..3d3befc 100644
--- a/src/PuppeteerCaptureViaHeadlessExperimental.ts
+++ b/src/PuppeteerCaptureViaHeadlessExperimental.ts
@@ -31,7 +31,7 @@ export class PuppeteerCaptureViaHeadlessExperimental extends PuppeteerCaptureBas
   }
 
   protected override async deconfigureSession (session: puppeteer.CDPSession): Promise<void> {
-    if (!this._page.isClosed()) {
+    if (session.connection() != null) {
       await session.send('HeadlessExperimental.disable')
     }
   }