chore: do not cache between reused context (#20052)

Fixes https://github.com/microsoft/playwright/issues/19926

packages/playwright-core/src/server/browserContext.ts

@@ -209,6 +209,7 @@ export abstract class BrowserContext extends SdkObject {
     await this.setGeolocation(this._options.geolocation);
     await this.setOffline(!!this._options.offline);
     await this.setUserAgent(this._options.userAgent);
+    await this.clearCache();
     await this._resetCookies();
 
     await page?.resetForReuse(metadata);
@@ -246,6 +247,7 @@ export abstract class BrowserContext extends SdkObject {
   abstract setUserAgent(userAgent: string | undefined): Promise<void>;
   abstract setOffline(offline: boolean): Promise<void>;
   abstract cancelDownload(uuid: string): Promise<void>;
+  abstract clearCache(): Promise<void>;
   protected abstract doGetCookies(urls: string[]): Promise<channels.NetworkCookie[]>;
   protected abstract doGrantPermissions(origin: string, permissions: string[]): Promise<void>;
   protected abstract doClearPermissions(): Promise<void>;

packages/playwright-core/src/server/chromium/crBrowser.ts

@@ -543,6 +543,11 @@ export class CRBrowserContext extends BrowserContext {
     }
   }
 
+  override async clearCache(): Promise<void> {
+    for (const page of this._crPages())
+      await page._mainFrameSession._networkManager.clearCache();
+  }
+
   async cancelDownload(guid: string) {
     // The upstream CDP method is implemented in a way that no explicit error would be given
     // regarding the requested `guid`, even if the download is in a state not suitable for

packages/playwright-core/src/server/chromium/crNetworkManager.ts

@@ -127,6 +127,14 @@ export class CRNetworkManager {
     }
   }
 
+  async clearCache() {
+    // Sending 'Network.setCacheDisabled' with 'cacheDisabled = true' will clear the MemoryCache.
+    await this._client.send('Network.setCacheDisabled', { cacheDisabled: true });
+    if (!this._protocolRequestInterceptionEnabled)
+      await this._client.send('Network.setCacheDisabled', { cacheDisabled: false });
+    await this._client.send('Network.clearBrowserCache');
+  }
+
   _onRequestWillBeSent(workerFrame: frames.Frame | undefined, event: Protocol.Network.requestWillBeSentPayload) {
     // Request interception doesn't happen for data URLs with Network Service.
     if (this._protocolRequestInterceptionEnabled && !event.request.url.startsWith('data:')) {

packages/playwright-core/src/server/firefox/ffBrowser.ts

@@ -358,6 +358,11 @@ export class FFBrowserContext extends BrowserContext {
 
   onClosePersistent() {}
 
+  override async clearCache(): Promise<void> {
+    // Clearing only the context cache does not work: https://bugzilla.mozilla.org/show_bug.cgi?id=1819147
+    await this._browser._connection.send('Browser.clearCache');
+  }
+
   async doClose() {
     if (!this._browserContextId) {
       if (this._options.recordVideo) {

packages/playwright-core/src/server/webkit/wkBrowser.ts

@@ -339,6 +339,13 @@ export class WKBrowserContext extends BrowserContext {
 
   onClosePersistent() {}
 
+  override async clearCache(): Promise<void> {
+    // We use ephemeral contexts so there is no disk cache.
+    await this._browser._browserSession.send('Playwright.clearMemoryCache', {
+      browserContextId: this._browserContextId!
+    });
+  }
+
   async doClose() {
     if (!this._browserContextId) {
       await Promise.all(this._wkPages().map(wkPage => wkPage._stopVideo()));

tests/library/browsercontext-reuse.spec.ts

@@ -127,3 +127,58 @@ test('should reset serviceworker that hangs in importScripts', async ({ reusedCo
   await page.goto(server.PREFIX + '/page.html');
   await expect(page).toHaveTitle('Page Title');
 });
+
+test('should not cache resources', async ({ reusedContext, server }) => {
+  test.info().annotations.push({ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/19926' });
+  const requestCountMap = new Map<string, number>();
+  server.setRoute('/page.html', (req, res) => {
+    res.setHeader('Content-Type', 'text/html');
+    res.setHeader(`Cache-Control`, `max-age=3600`);
+    const requestCount = requestCountMap.get(req.url) || 0;
+    res.end(`
+    <!DOCTYPE html>
+    <html>
+      <head>
+        <meta charset="UTF-8">
+        <title>Count: ${requestCount}</title>
+        <link rel="stylesheet" href="style.css">
+        <script>
+          fetch('simple.json').then(() => {});
+        </script>
+      </head>
+    </html>
+    `);
+    requestCountMap.set(req.url, requestCount + 1);
+  });
+  server.setRoute('/style.css', (req, res) => {
+    res.setHeader('Content-Type', 'text/css');
+    res.setHeader(`Cache-Control`, `max-age=3600`);
+    res.end(`body { background-color: red; }`);
+    requestCountMap.set(req.url, (requestCountMap.get(req.url) || 0) + 1);
+  });
+  server.setRoute('/simple.json', (req, res) => {
+    res.setHeader(`Cache-Control`, `max-age=3600`);
+    res.setHeader('Content-Type', 'application/json');
+    res.end(`{ "foo": "bar" }`);
+    requestCountMap.set(req.url, (requestCountMap.get(req.url) || 0) + 1);
+  });
+
+  {
+    const context = await reusedContext();
+    const page = await context.newPage();
+    await page.goto(server.PREFIX + '/page.html');
+    await expect(page).toHaveTitle('Count: 0');
+    expect(requestCountMap.get('/page.html')).toBe(1);
+    expect(requestCountMap.get('/style.css')).toBe(1);
+    expect(requestCountMap.get('/simple.json')).toBe(1);
+  }
+  {
+    const context = await reusedContext();
+    const page = context.pages()[0];
+    await page.goto(server.PREFIX + '/page.html');
+    await expect(page).toHaveTitle('Count: 1');
+    expect(requestCountMap.get('/page.html')).toBe(2);
+    expect(requestCountMap.get('/style.css')).toBe(2);
+    expect(requestCountMap.get('/simple.json')).toBe(2);
+  }
+});