From f5e611c8a38f97c7e6a3b2df9cb58eb1add80423 Mon Sep 17 00:00:00 2001
From: Devin Rousso <devinrousso@microsoft.com>
Date: Fri, 19 Jun 2026 16:02:18 -0600
Subject: [PATCH] feat(webview): support `setUserAgent`

---
 .../src/server/webkit/webview/wvBrowser.ts                | 7 ++++++-
 .../playwright-core/src/server/webkit/webview/wvPage.ts   | 8 ++++++++
 packages/playwright-core/src/server/webkit/wkPage.ts      | 4 ++--
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/packages/playwright-core/src/server/webkit/webview/wvBrowser.ts b/packages/playwright-core/src/server/webkit/webview/wvBrowser.ts
index 313f3ab0ae8a9..4bbdc1833b014 100644
--- a/packages/playwright-core/src/server/webkit/webview/wvBrowser.ts
+++ b/packages/playwright-core/src/server/webkit/webview/wvBrowser.ts
@@ -334,6 +334,12 @@ export class WVBrowserContext extends BrowserContext {
       await (page.delegate as WVPage).updateExtraHTTPHeaders();
   }
 
+  async setUserAgent(userAgent: string | undefined): Promise<void> {
+    this._options.userAgent = userAgent;
+    for (const page of this.pages())
+      await (page.delegate as WVPage).updateUserAgent();
+  }
+
   async doAddInitScript(initScript: InitScript) {
     for (const page of this.pages())
       await (page.delegate as WVPage)._updateBootstrapScript();
@@ -360,7 +366,6 @@ export class WVBrowserContext extends BrowserContext {
   override async clearCache(): Promise<void> { throw new Error('Method not implemented.'); }
   override async doClose(reason: string | undefined): Promise<void | 'close-browser'> { throw new Error('Method not implemented.'); }
   override async cancelDownload(uuid: string) { throw new Error('Method not implemented.'); }
-  override async setUserAgent(userAgent: string | undefined): Promise<void> { throw new Error('Method not implemented.'); }
   protected override async doSetHTTPCredentials(httpCredentials?: types.Credentials): Promise<void> { throw new Error('Method not implemented.'); }
   protected override async doUpdateOffline(): Promise<void> { throw new Error('Method not implemented.'); }
 }
diff --git a/packages/playwright-core/src/server/webkit/webview/wvPage.ts b/packages/playwright-core/src/server/webkit/webview/wvPage.ts
index 1aec197f8f03d..e8519b9bac5e6 100644
--- a/packages/playwright-core/src/server/webkit/webview/wvPage.ts
+++ b/packages/playwright-core/src/server/webkit/webview/wvPage.ts
@@ -218,6 +218,9 @@ export class WVPage implements PageDelegate {
     const emulatedMedia = this._page.emulatedMedia();
     if (emulatedMedia.media || emulatedMedia.colorScheme || emulatedMedia.reducedMotion || emulatedMedia.contrast)
       await WVPage._setEmulateMedia(session, emulatedMedia.media, emulatedMedia.colorScheme, emulatedMedia.reducedMotion, emulatedMedia.contrast);
+    const contextOptions = this._browserContext._options;
+    if (contextOptions.userAgent)
+      await session.sendMayFail('Page.overrideUserAgent', { value: contextOptions.userAgent });
     if (this._page.needsRequestInterception()) {
       await Promise.all([
         session.sendMayFail('Network.setInterceptionEnabled', { enabled: true }),
@@ -601,6 +604,11 @@ export class WVPage implements PageDelegate {
     return headers;
   }
 
+  async updateUserAgent(): Promise<void> {
+    const contextOptions = this._browserContext._options;
+    await this._updateState('Page.overrideUserAgent', { value: contextOptions.userAgent });
+  }
+
   async bringToFront(): Promise<void> {
   }
 
diff --git a/packages/playwright-core/src/server/webkit/wkPage.ts b/packages/playwright-core/src/server/webkit/wkPage.ts
index 9396d5b20486c..f744f1cd634b8 100644
--- a/packages/playwright-core/src/server/webkit/wkPage.ts
+++ b/packages/playwright-core/src/server/webkit/wkPage.ts
@@ -188,7 +188,7 @@ export class WKPage implements PageDelegate {
 
     const contextOptions = this._browserContext._options;
     if (contextOptions.userAgent)
-      promises.push(this.updateUserAgent());
+      promises.push(session.send('Page.overrideUserAgent', { value: contextOptions.userAgent }));
     const emulatedMedia = this._page.emulatedMedia();
     if (emulatedMedia.media || emulatedMedia.colorScheme || emulatedMedia.reducedMotion || emulatedMedia.forcedColors || emulatedMedia.contrast)
       promises.push(WKPage._setEmulateMedia(session, emulatedMedia.media, emulatedMedia.colorScheme, emulatedMedia.reducedMotion, emulatedMedia.forcedColors, emulatedMedia.contrast));
@@ -694,7 +694,7 @@ export class WKPage implements PageDelegate {
 
   async updateUserAgent(): Promise<void> {
     const contextOptions = this._browserContext._options;
-    this._updateState('Page.overrideUserAgent', { value: contextOptions.userAgent });
+    await this._updateState('Page.overrideUserAgent', { value: contextOptions.userAgent });
   }
 
   async bringToFront(): Promise<void> {