fix(chromium): preserve binary response body with text content-type

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

@@ -379,17 +379,28 @@ export class CRNetworkManager {
     const getResponseBody = async () => {
       const contentLengthHeader = Object.entries(responsePayload.headers).find(header => header[0].toLowerCase() === 'content-length');
       const expectedLength = contentLengthHeader ? +contentLengthHeader[1] : undefined;
+      const hasContentEncoding = Object.keys(responsePayload.headers).some(h => h.toLowerCase() === 'content-encoding');
 
       const session = request.session;
       const response = await session.send('Network.getResponseBody', { requestId: request._requestId });
-      if (response.body || !expectedLength)
-        return Buffer.from(response.body, response.base64Encoded ? 'base64' : 'utf8');
+      if (response.body || !expectedLength) {
+        const buffer = Buffer.from(response.body, response.base64Encoded ? 'base64' : 'utf8');
+        // When CDP returns non-base64 text for a response with Content-Length,
+        // it may have decoded binary data as UTF-8, corrupting non-UTF-8 bytes.
+        // Detect this by comparing Content-Length with actual byte length,
+        // and fall through to re-fetch via loadNetworkResource.
+        // Skip the check when Content-Encoding is present (gzip, br, etc.)
+        // because Content-Length refers to the encoded size, not the decoded body.
+        if (response.base64Encoded || !expectedLength || hasContentEncoding || buffer.byteLength === expectedLength)
+          return buffer;
+      }
 
       // Make sure no network requests sent while reading the body for fulfilled requests.
       if (request._originalRequestRoute?._fulfilled)
         return Buffer.from('');
 
-      // For <link prefetch we are going to receive empty body with non-empty content-length expectation. Reach out for the actual content.
+      // Re-fetch the content from cache via loadNetworkResource.
+      // This path is also used for <link prefetch> which returns an empty body.
       const resource = await session.send('Network.loadNetworkResource', { url: request.request.url(), frameId: this._serviceWorker ? undefined : request.request.frame()!._id, options: { disableCache: false, includeCredentials: true } });
       const chunks: Buffer[] = [];
       while (resource.resource.stream) {

tests/page/page-goto.spec.ts

@@ -745,8 +745,7 @@ it('should work with lazy loading iframes', async ({ page, server, isAndroid })
 });
 
 it('should report raw buffer for main resource', async ({ page, server, browserName, platform, channel }) => {
-  it.fail(browserName === 'chromium', 'Chromium sends main resource as text');
-  it.fail(browserName === 'webkit' && platform === 'win32' && channel !== 'webkit-wsl', 'Same here');
+  it.fail(browserName === 'webkit' && platform === 'win32' && channel !== 'webkit-wsl', 'WebKit on Windows sends main resource as text');
 
   server.setRoute('/empty.html', (req, res) => {
     res.statusCode = 200;

tests/page/page-network-response.spec.ts

@@ -149,6 +149,26 @@ it('should return body with compression', async ({ page, server, asset }) => {
   expect(responseBuffer.equals(imageBuffer)).toBe(true);
 });
 
+it('should return binary body with text content-type', async ({ page, server, browserName }) => {
+  it.skip(browserName !== 'chromium', 'Binary body preservation is currently Chromium-specific');
+  // Binary data with bytes that are invalid UTF-8.
+  const binaryData = Buffer.from([0x80, 0x81, 0x82, 0xFF, 0xFE, 0x00, 0x01, 0x02]);
+  server.setRoute('/binary-as-text', (req, res) => {
+    res.writeHead(200, {
+      'Content-Type': 'text/plain;charset=UTF-8',
+      'Content-Length': binaryData.length,
+    });
+    res.end(binaryData);
+  });
+  await page.goto(server.EMPTY_PAGE);
+  const [response] = await Promise.all([
+    page.waitForResponse(server.PREFIX + '/binary-as-text'),
+    page.evaluate(url => fetch(url), server.PREFIX + '/binary-as-text'),
+  ]);
+  const body = await response.body();
+  expect(body.equals(binaryData)).toBe(true);
+});
+
 it('should return status text', async ({ page, server }) => {
   server.setRoute('/cool', (req, res) => {
     res.writeHead(200, 'cool!');