Add client_session context entity if anonymous tracking with session tracking is enabled (close snowplow#1124)

PR snowplow#1135

Author: matus-tomlein

common/changes/@snowplow/browser-tracker-core/issue-1124-client_session_2022-12-23-13-19.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@snowplow/browser-tracker-core",
+      "comment": "Add client_session context entity if anonymous tracking with session tracking is enabled (#1124)",
+      "type": "none"
+    }
+  ],
+  "packageName": "@snowplow/browser-tracker-core"
+}

libraries/browser-tracker-core/src/tracker/id_cookie.ts

@@ -300,14 +300,20 @@ export function serializeIdCookie(idCookie: ParsedIdCookie) {
  * @param configStateStorageStrategy Cookie storage strategy
  * @returns Client session context entity
  */
-export function clientSessionFromIdCookie(idCookie: ParsedIdCookie, configStateStorageStrategy: string) {
+export function clientSessionFromIdCookie(
+  idCookie: ParsedIdCookie,
+  configStateStorageStrategy: string,
+  configAnonymousTracking: boolean
+) {
   const firstEventTsInMs = idCookie[firstEventTsInMsIndex];
   const clientSession: ClientSession = {
-    userId: idCookie[domainUserIdIndex],
+    userId: configAnonymousTracking
+      ? '00000000-0000-0000-0000-000000000000' // TODO: use uuid.NIL when we upgrade to uuid v8.3
+      : idCookie[domainUserIdIndex],
     sessionId: idCookie[sessionIdIndex],
     eventIndex: idCookie[eventIndexIndex],
     sessionIndex: idCookie[visitCountIndex],
-    previousSessionId: idCookie[previousSessionIdIndex] || null,
+    previousSessionId: configAnonymousTracking ? null : idCookie[previousSessionIdIndex] || null,
     storageMechanism: configStateStorageStrategy == 'localStorage' ? 'LOCAL_STORAGE' : 'COOKIE_1',
     firstEventId: idCookie[firstEventIdIndex] || null,
     firstEventTimestamp: firstEventTsInMs ? new Date(firstEventTsInMs).toISOString() : null,

libraries/browser-tracker-core/src/tracker/index.ts

@@ -787,8 +787,11 @@ export function Tracker(
           // Add the page URL last as it may take us over the IE limit (and we don't always need it)
           payloadBuilder.add('url', purify(configCustomUrl || locationHrefAlias));
 
-          if (configSessionContext && !configAnonymousSessionTracking && !configAnonymousTracking) {
-            addSessionContextToPayload(payloadBuilder, clientSessionFromIdCookie(idCookie, configStateStorageStrategy));
+          if (configSessionContext && (!configAnonymousTracking || configAnonymousSessionTracking)) {
+            addSessionContextToPayload(
+              payloadBuilder,
+              clientSessionFromIdCookie(idCookie, configStateStorageStrategy, configAnonymousTracking)
+            );
           }
 
           // Update cookies

libraries/browser-tracker-core/test/id_cookie.test.ts

@@ -262,7 +262,7 @@ describe('serializeIdCookie', () => {
 describe('clientSessionFromIdCookie', () => {
   it('Correctly fills out the properties', () => {
     let idCookie = parseIdCookie('def.1653632272.10.1653632282.1653632262.ses.previous.fid.1653638673483.9', '', '', 0);
-    let clientSession = clientSessionFromIdCookie(idCookie, 'cookieAndLocalStorage');
+    let clientSession = clientSessionFromIdCookie(idCookie, 'cookieAndLocalStorage', false);
 
     expect(clientSession.userId).toBe('def');
     expect(clientSession.sessionId).toBe('ses');
@@ -273,4 +273,18 @@ describe('clientSessionFromIdCookie', () => {
     expect(clientSession.firstEventId).toBe('fid');
     expect(clientSession.firstEventTimestamp).toBe('2022-05-27T08:04:33.483Z');
   });
+
+  it('Anonymises userId and previousSessionId when anonymous tracking', () => {
+    let idCookie = parseIdCookie('def.1653632272.10.1653632282.1653632262.ses.previous.fid.1653638673483.9', '', '', 0);
+    let clientSession = clientSessionFromIdCookie(idCookie, 'cookieAndLocalStorage', true);
+
+    expect(clientSession.userId).toBe('00000000-0000-0000-0000-000000000000');
+    expect(clientSession.sessionId).toBe('ses');
+    expect(clientSession.previousSessionId).toBeNull;
+    expect(clientSession.eventIndex).toBe(9);
+    expect(clientSession.sessionIndex).toBe(10);
+    expect(clientSession.storageMechanism).toBe('COOKIE_1');
+    expect(clientSession.firstEventId).toBe('fid');
+    expect(clientSession.firstEventTimestamp).toBe('2022-05-27T08:04:33.483Z');
+  });
 });

libraries/browser-tracker-core/test/tracker/session_data.test.ts

@@ -28,6 +28,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+import { TrackerConfiguration } from '../../dist/index.module';
 import { addTracker, SharedState } from '../../src';
 import { createTestIdCookie, createTestSessionIdCookie } from '../helpers';
 
@@ -54,45 +55,45 @@ describe('Tracker API: ', () => {
   });
 
   it('Sets initial domain session index on first session', () => {
-    const tracker = addTracker('sp1', 'sp1', '', '', new SharedState());
+    const tracker = createTracker();
 
     expect(tracker?.getDomainSessionIndex()).toEqual(1);
   });
 
   it('Sets correct domain session index on new session', () => {
     const initialSessionIndex = 1;
     document.cookie = createTestIdCookie({ visitCount: initialSessionIndex });
-    const tracker = addTracker('sp2', 'sp2', '', '', new SharedState());
+    const tracker = createTracker();
 
     expect(tracker?.getDomainSessionIndex()).toEqual(initialSessionIndex + 1);
   });
 
   it('Sets correct domain session index on existing session', () => {
     const initialSessionIndex = 2;
     document.cookie = createTestIdCookie({ visitCount: initialSessionIndex }) + ' ' + createTestSessionIdCookie();
-    const tracker = addTracker('sp3', 'sp3', '', '', new SharedState());
+    const tracker = createTracker();
 
     expect(tracker?.getDomainSessionIndex()).toEqual(initialSessionIndex);
   });
 
   it('Sets correct domain session index (1) after clearUserData() on existing session', () => {
     const initialSessionIndex = 2;
     document.cookie = createTestIdCookie({ visitCount: initialSessionIndex }) + ' ' + createTestSessionIdCookie();
-    const tracker = addTracker('sp4', 'sp4', '', '', new SharedState());
+    const tracker = createTracker();
     expect(tracker?.getDomainSessionIndex()).toEqual(initialSessionIndex);
 
     tracker?.clearUserData();
     expect(tracker?.getDomainSessionIndex()).toEqual(1);
   });
 
   it('Sets correct domain session index anonymous track', () => {
-    const tracker = addTracker('sp5', 'sp5', '', '', new SharedState(), { anonymousTracking: true });
+    const tracker = createTracker({ anonymousTracking: true });
     expect(tracker?.getDomainSessionIndex()).toEqual(1);
   });
 
   it('Retains correct domain session index on opt-out cookie present', () => {
     const optOutCookieName = 'optOut';
-    const tracker = addTracker('sp6', 'sp6', '', '', new SharedState());
+    const tracker = createTracker();
     tracker?.setOptOutCookie(optOutCookieName);
     document.cookie = `${optOutCookieName}=1;`;
 
@@ -102,10 +103,73 @@ describe('Tracker API: ', () => {
 
   it('Sets correct domain session index after session expiration', () => {
     // Session timeout is in seconds
-    const tracker = addTracker('sp7', 'sp7', '', '', new SharedState(), { sessionCookieTimeout: 1 });
+    const tracker = createTracker({ sessionCookieTimeout: 1 });
     // Advance timer by more than one second
     jest.advanceTimersByTime(1001);
     tracker?.trackPageView({ title: 'my page' });
     expect(tracker?.getDomainSessionIndex()).toEqual(2);
   });
+
+  it('Adds the client session context entity when enabled', (done) => {
+    const tracker = createTracker({
+      contexts: { session: true },
+      encodeBase64: false,
+      plugins: [
+        {
+          afterTrack: (payload) => {
+            let context = payload.co as string;
+            expect(context).toContain('client_session');
+            done();
+          },
+        },
+      ],
+    });
+
+    tracker?.trackPageView();
+  });
+
+  it('Adds the client session context entity when anonymous session tracking', (done) => {
+    const tracker = createTracker({
+      contexts: { session: true },
+      encodeBase64: false,
+      anonymousTracking: { withSessionTracking: true },
+      plugins: [
+        {
+          afterTrack: (payload) => {
+            let context = payload.co as string;
+            expect(context).toContain('client_session');
+            expect(context).toContain('"userId":"00000000-0000-0000-0000-000000000000"');
+            expect(context).toContain('"previousSessionId":null');
+            done();
+          },
+        },
+      ],
+    });
+
+    tracker?.trackPageView();
+  });
+
+  it("Doesn't add the client session context entity when anonymous tracking without session tracking", (done) => {
+    const tracker = createTracker({
+      contexts: { session: true },
+      encodeBase64: false,
+      anonymousTracking: true,
+      plugins: [
+        {
+          afterTrack: (payload) => {
+            let context = payload.co as string;
+            expect(context).not.toContain('client_session');
+            done();
+          },
+        },
+      ],
+    });
+
+    tracker?.trackPageView();
+  });
 });
+
+function createTracker(configuration?: TrackerConfiguration) {
+  let id = 'sp-' + Math.random();
+  return addTracker(id, id, '', '', new SharedState(), configuration);
+}