fix(browser-plugin-media-tracking): match the data: scheme as a prefix

dataUrlHandler used a substring check, which was wrong in both directions: it
replaced valid URLs that merely contain 'data:' somewhere (a path segment such
as 'metadata:9' matches) and it missed an uppercase 'DATA:' scheme, shipping the
large base64 payload the function exists to avoid. URI schemes are
case-insensitive per RFC 3986.

Match /^data:/i instead, and cover both directions with tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: matus-tomlein

plugins/browser-plugin-media-tracking/src/helperFunctions.ts

@@ -47,7 +47,11 @@ export function getDuration(el: HTMLAudioElement | HTMLVideoElement): number | n
 export const DATA_URL_PLACEHOLDER = 'data:';
 
 export function dataUrlHandler(url: string): string {
-  if (url.indexOf('data:') !== -1) {
+  // Match the `data:` scheme only at the start of the string, case-insensitively as
+  // RFC 3986 specifies. A substring check would both replace valid URLs that merely
+  // contain 'data:' (e.g. a path segment 'metadata:9') and miss an uppercase 'DATA:'
+  // scheme, shipping the large payload this is meant to avoid.
+  if (/^data:/i.test(url)) {
     return DATA_URL_PLACEHOLDER;
   }
   return url;

plugins/browser-plugin-media-tracking/tests/media.test.ts

@@ -64,6 +64,26 @@ describe('dataUrlHandler', () => {
     const output = dataUrlHandler(test_url);
     expect(output).toBe('data:');
   });
+
+  it('matches the data: scheme case-insensitively', () => {
+    // URI schemes are case-insensitive per RFC 3986, so this is a real data URI and
+    // its payload must not be sent.
+    const test_url = 'DATA:image/png;base64,iVBORw0KGgoAA5ErkJggg==';
+    const output = dataUrlHandler(test_url);
+    expect(output).toBe('data:');
+  });
+
+  it('keeps urls that merely contain data: outside the scheme', () => {
+    // 'data:' has to be matched as a scheme, not as a substring, or valid URLs get
+    // replaced by the placeholder.
+    for (const test_url of [
+      'https://example.com/metadata:9/video.mp4',
+      'https://example.com/data:foo/video.mp4',
+      'https://example.com/video.mp4?ref=data:x',
+    ]) {
+      expect(dataUrlHandler(test_url)).toBe(test_url);
+    }
+  });
 });
 
 describe('getUriFileExtension', () => {