feat: Add base64-encoded MPID query parameter for Google Marketing Platform cookie sync

When the cookie sync partner is DoubleclickDFP (module ID 41), append
a `google_hm` query parameter containing the base64-encoded MPID to the
cookie sync URL.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rmi22186

src/cookieSyncManager.ts

@@ -137,8 +137,11 @@ export default function CookieSyncManager(
             // It is optional but to simplify the code, we add it for all Trade
             // // Desk cookie syncs.
             const domain = moduleId === PARTNER_MODULE_IDS.TradeDesk ? window.location.hostname : undefined;
-            // Add domain parameter for Trade Desk
-            const fullUrl = createCookieSyncUrl(mpid, pixelUrl, redirectUrl, domain);
+
+            // Google Marketing Platform requires a base64-encoded MPID query parameter
+            const base64Mpid = moduleId === PARTNER_MODULE_IDS.DoubleclickDFP ? btoa(mpid) : undefined;
+
+            const fullUrl = createCookieSyncUrl(mpid, pixelUrl, redirectUrl, domain, base64Mpid);
 
             self.performCookieSync(
                 fullUrl,

src/utils.ts

@@ -207,26 +207,32 @@ const createCookieSyncUrl = (
     mpid: MPID,
     pixelUrl: string,
     redirectUrl?: string,
-    domain?: string
+    domain?: string,
+    base64Mpid?: string
 ): string => {
     const modifiedPixelUrl = replaceAmpWithAmpersand(pixelUrl);
     const modifiedDirectUrl = redirectUrl
         ? replaceAmpWithAmpersand(redirectUrl)
         : null;
 
     let url = replaceMPID(modifiedPixelUrl, mpid);
-    
+
     const redirect = modifiedDirectUrl
         ? replaceMPID(modifiedDirectUrl, mpid)
         : '';
-    
+
     let fullUrl = url + encodeURIComponent(redirect);
-    
+
     if (domain) {
         const separator = fullUrl.includes('?') ? '&' : '?';
         fullUrl += `${separator}domain=${domain}`;
     }
-    
+
+    if (base64Mpid) {
+        const separator = fullUrl.includes('?') ? '&' : '?';
+        fullUrl += `${separator}google_hm=${base64Mpid}`;
+    }
+
     return fullUrl;
 };
 

test/jest/cookieSyncManager.spec.ts

@@ -776,6 +776,92 @@ describe('CookieSyncManager', () => {
                 );
             });
         });
+
+        describe('Google Marketing Platform (DoubleclickDFP) base64 MPID', () => {
+            it('should add base64-encoded MPID parameter for DoubleclickDFP (module ID 41)', () => {
+                const gmpPixelSettings: IPixelConfiguration = {
+                    ...pixelSettings,
+                    moduleId: PARTNER_MODULE_IDS.DoubleclickDFP, // 41
+                    pixelUrl: 'https://cm.g.doubleclick.net/pixel?google_nid=abc123',
+                    redirectUrl: '',
+                };
+
+                const mockMPInstance = ({
+                    _Store: {
+                        webviewBridgeEnabled: false,
+                        pixelConfigurations: [gmpPixelSettings],
+                    },
+                    _CookieConsentManager: { getNoFunctional: jest.fn().mockReturnValue(false) },
+                    _Persistence: {
+                        getPersistence: () => ({testMPID: {
+                            csd: {}
+                        }}),
+                    },
+                    _Consent: {
+                        isEnabledForUserConsent: jest.fn().mockReturnValue(true),
+                    },
+                    Identity: {
+                        getCurrentUser: jest.fn().mockReturnValue({
+                            getMPID: () => testMPID,
+                        }),
+                    },
+                } as unknown) as IMParticleWebSDKInstance;
+
+                const cookieSyncManager = new CookieSyncManager(mockMPInstance);
+                cookieSyncManager.performCookieSync = jest.fn();
+
+                cookieSyncManager.attemptCookieSync(testMPID, true);
+
+                expect(cookieSyncManager.performCookieSync).toHaveBeenCalledWith(
+                    `https://cm.g.doubleclick.net/pixel?google_nid=abc123&google_hm=${btoa(testMPID)}`,
+                    '41',
+                    testMPID,
+                    {},
+                );
+            });
+
+            it('should not add base64 MPID parameter for non-DoubleclickDFP partners', () => {
+                const appNexusPixelSettings: IPixelConfiguration = {
+                    ...pixelSettings,
+                    moduleId: PARTNER_MODULE_IDS.AppNexus, // 50
+                    pixelUrl: 'https://ib.adnxs.com/cookie_sync?adv=abc123',
+                    redirectUrl: '',
+                };
+
+                const mockMPInstance = ({
+                    _Store: {
+                        webviewBridgeEnabled: false,
+                        pixelConfigurations: [appNexusPixelSettings],
+                    },
+                    _CookieConsentManager: { getNoFunctional: jest.fn().mockReturnValue(false) },
+                    _Persistence: {
+                        getPersistence: () => ({testMPID: {
+                            csd: {}
+                        }}),
+                    },
+                    _Consent: {
+                        isEnabledForUserConsent: jest.fn().mockReturnValue(true),
+                    },
+                    Identity: {
+                        getCurrentUser: jest.fn().mockReturnValue({
+                            getMPID: () => testMPID,
+                        }),
+                    },
+                } as unknown) as IMParticleWebSDKInstance;
+
+                const cookieSyncManager = new CookieSyncManager(mockMPInstance);
+                cookieSyncManager.performCookieSync = jest.fn();
+
+                cookieSyncManager.attemptCookieSync(testMPID, true);
+
+                expect(cookieSyncManager.performCookieSync).toHaveBeenCalledWith(
+                    'https://ib.adnxs.com/cookie_sync?adv=abc123',
+                    '50',
+                    testMPID,
+                    {},
+                );
+            });
+        });
     });
 
     describe('PARTNER_MODULE_IDS', () => {