From 5fdb57b3dc3cc12f7f2993260efb70ae0ded92b9 Mon Sep 17 00:00:00 2001
From: Sebastian Kreft <sk-@users.noreply.github.com>
Date: Fri, 10 Nov 2023 10:59:05 -0300
Subject: [PATCH] feat: propagate additional products (#213)

In case customers want to attribute purchases to banners they need to
specify a product and a resolved bid as inherit. In such a case we would
grab the resolved id id that was stored in session storage in the
previous click.

There are some caveats with this approach:
1) If there's a mistake and an inherit resolved bid is used in a page
which is not the target of a banner, then the events will fail. 2) It
could happen that the user manually changes the url to a banner's
destination page and in that case we would report the events to the
wrong banner. 3) This won't always work if session storage is not
available (support is 97.4%
https://caniuse.com/mdn-api_window_sessionstorage). We have a fallback
using an in memory cache, but that would only work if the page it's not
reloaded (Vue, React, etc)
---
 README.md             | 25 ++++++++++++++++++++++---
 mocks/api-server.ts   | 14 ++++++++++++--
 src/detector.ts       | 40 ++++++++++++++++++++++++++++++++++++----
 src/events.ts         |  2 ++
 src/store.ts          | 24 ++++++++++++++++++++++++
 tests/browser-test.ts | 21 +++++++++++++++++++++
 tests/test.html       |  7 +++++++
 7 files changed, 124 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 99bfbf6..aea3dbf 100644
--- a/README.md
+++ b/README.md
@@ -39,13 +39,21 @@ Either mix quotes (single/double) or escape certain characters inside your value
 const newvalue = currentvalue.replace('"', "&quot;").replace("'", "&apos;"); // etc.
 ```
 
-Pass said values to your html:
+Add the following markup to promoted products: 
+```html
+<div
+  class="product"
+  data-ts-resolved-bid="<resolvedBidId>"
+>
+  ...
+</div>
+```
 
+and the following for organic products (which is optional)
 ```html
 <div
   class="product"
   data-ts-product="<productId>"
-  data-ts-resolved-bid="<resolvedBidId>"
 >
   ...
 </div>
@@ -63,7 +71,7 @@ Additionally, in case not all the container is clickable (i.e., does not produce
 </div>
 ```
 
-Finally, adding further information to purchases can be made by passing the `ts-data-items` JSON array:
+Adding further information to purchases can be made by passing the `ts-data-items` JSON array:
 
 ```html
 <div
@@ -74,6 +82,17 @@ Finally, adding further information to purchases can be made by passing the `ts-
 </div>
 ```
 
+Finally, in case you are using banners and want to have further control on the attributable products you need to add the following markup in the banner's destination page.
+
+```html
+<div
+  class="product"
+  data-ts-product="<productId>"
+  data-ts-resolved-bid="inherit"
+>
+  ...
+</div>
+```
 # E2E tests
 
 Execute `npm run test:e2e`, at the end it will show you the url you need to visit to test the library.
diff --git a/mocks/api-server.ts b/mocks/api-server.ts
index 1ff34cb..2783c16 100644
--- a/mocks/api-server.ts
+++ b/mocks/api-server.ts
@@ -58,11 +58,21 @@ app.post("/:session/v2/events", (req, res) => {
   const payload = req.body;
   let totalEvents = 0;
   for (const event of payload.impressions ?? []) {
-    addEvent(event.entity.id, "impression", event, session);
+    addEvent(
+      event.entity?.id ?? event.additionalAttribution?.id,
+      "impression",
+      event,
+      session,
+    );
     totalEvents++;
   }
   for (const event of payload.clicks ?? []) {
-    addEvent(event.entity.id, "click", event, session);
+    addEvent(
+      event.entity?.id ?? event.additionalAttribution?.id,
+      "click",
+      event,
+      session,
+    );
     totalEvents++;
   }
   for (const event of payload.purchases ?? []) {
diff --git a/src/detector.ts b/src/detector.ts
index 5dd7e89..7342534 100644
--- a/src/detector.ts
+++ b/src/detector.ts
@@ -1,11 +1,13 @@
 import { TopsortEvent, Entity } from "./events";
 import { ProcessorResult, Queue } from "./queue";
 import { reportEvent } from "./reporter";
+import { BidStore } from "./store";
 
 const MAX_EVENTS_SIZE = 2500;
 // See https://support.google.com/admanager/answer/4524488?hl=en
 const INTERSECTION_THRESHOLD = 0.5;
 let seenEvents = new Set<string>();
+const bidStore = new BidStore("ts-b");
 
 /**
  * Generate an id.
@@ -71,6 +73,13 @@ function getApiPayload(event: ProductEvent): TopsortEvent {
       id: event.product,
     };
   }
+  let additionalAttribution: Entity | undefined = undefined;
+  if (event.additionalProduct) {
+    additionalAttribution = {
+      type: "product",
+      id: event.additionalProduct,
+    };
+  }
   const t = new Date(event.t).toISOString();
   switch (eventType) {
     case "Click":
@@ -79,6 +88,7 @@ function getApiPayload(event: ProductEvent): TopsortEvent {
           {
             resolvedBidId: event.bid,
             entity,
+            additionalAttribution,
             placement,
             occurredAt: t,
             opaqueUserId: event.uid,
@@ -92,6 +102,7 @@ function getApiPayload(event: ProductEvent): TopsortEvent {
           {
             resolvedBidId: event.bid,
             entity,
+            additionalAttribution,
             placement,
             occurredAt: t,
             opaqueUserId: event.uid,
@@ -153,6 +164,7 @@ interface Purchase {
 interface ProductEvent {
   type: EventType;
   product?: string;
+  additionalProduct?: string;
   bid?: string;
   t: number;
   page: string;
@@ -183,7 +195,12 @@ function logEvent(info: ProductEvent, node: Node) {
 }
 
 function getId(event: ProductEvent): string {
-  return [event.page, event.type, event.product, event.bid].join("-");
+  return [
+    event.page,
+    event.type,
+    event.product ?? event.additionalProduct,
+    event.bid,
+  ].join("-");
 }
 
 function getPage(): string {
@@ -195,11 +212,22 @@ function getPage(): string {
 }
 
 function getEvent(type: EventType, node: HTMLElement): ProductEvent {
-  const product = node.dataset.tsProduct;
-  const bid = node.dataset.tsResolvedBid;
+  let product = node.dataset.tsProduct;
+  let bid = node.dataset.tsResolvedBid;
+  let additionalProduct: string | undefined = undefined;
+  if (
+    bid == "inherit" &&
+    product &&
+    (type == "Click" || type == "Impression")
+  ) {
+    bid = bidStore.get();
+    additionalProduct = product;
+    product = undefined;
+  }
   const event: ProductEvent = {
     type,
     product,
+    additionalProduct,
     bid,
     t: Date.now(),
     page: getPage(),
@@ -218,7 +246,11 @@ function interactionHandler(event: Event): void {
   }
   const container = event.currentTarget.closest(PRODUCT_SELECTOR);
   if (container && container instanceof HTMLElement) {
-    logEvent(getEvent("Click", container), container);
+    const interactionEvent = getEvent("Click", container);
+    logEvent(interactionEvent, container);
+    if (interactionEvent.bid) {
+      bidStore.set(interactionEvent.bid);
+    }
   }
 }
 
diff --git a/src/events.ts b/src/events.ts
index b537a29..73952b2 100644
--- a/src/events.ts
+++ b/src/events.ts
@@ -10,6 +10,7 @@ export interface Entity {
 interface Impression {
   resolvedBidId?: string;
   entity?: Entity;
+  additionalAttribution?: Entity;
   placement: Placement;
   occurredAt: string;
   opaqueUserId: string;
@@ -19,6 +20,7 @@ interface Impression {
 interface Click {
   resolvedBidId?: string;
   entity?: Entity;
+  additionalAttribution?: Entity;
   placement: Placement;
   occurredAt: string;
   opaqueUserId: string;
diff --git a/src/store.ts b/src/store.ts
index ba347d4..23e5e13 100644
--- a/src/store.ts
+++ b/src/store.ts
@@ -31,3 +31,27 @@ export class LocalStorageStore<T> implements Store<T> {
     this._storage.setItem(this._key, JSON.stringify(data));
   }
 }
+
+export class BidStore {
+  private _key: string;
+  private _storage: Storage;
+  private _bid: string | undefined;
+  constructor(key: string) {
+    this._key = key;
+    this._storage = window.sessionStorage;
+    this._bid = undefined;
+  }
+  get(): string | undefined {
+    try {
+      return this._storage.getItem(this._key) ?? undefined;
+    } catch (error) {
+      return this._bid;
+    }
+  }
+  set(bid: string): void {
+    this._bid = bid;
+    try {
+      this._storage.setItem(this._key, bid);
+    } catch (error) {}
+  }
+}
diff --git a/tests/browser-test.ts b/tests/browser-test.ts
index c57c225..be60e8e 100644
--- a/tests/browser-test.ts
+++ b/tests/browser-test.ts
@@ -42,6 +42,7 @@ interface ProductEvent {
   eventType?: string;
   placement?: Placement;
   entity?: Entity;
+  additionalAttribution?: Entity;
   resolvedBidId?: string | null;
   impressions?: Impression[];
   items?: Purchase[];
@@ -124,6 +125,12 @@ async function runTests() {
   const productArea = document.getElementById("click-area");
   productArea?.click();
 
+  // Click on banner and product
+  const banner = document.getElementById("banner");
+  banner?.click();
+  const bannerProduct = document.getElementById("banner-product");
+  bannerProduct?.click();
+
   // Add new product
   const newProduct = document.createElement("div");
   newProduct.dataset.tsProduct = "product-id-dyn-impression-1";
@@ -267,6 +274,20 @@ async function checkTests() {
     }),
   );
 
+  await setTestResult(
+    "test-banner-products",
+    checkEventExists("additional-product-banner", "click", {
+      additionalAttribution: {
+        id: "additional-product-banner",
+        type: "product",
+      },
+      placement: {
+        path: "/test.html",
+      },
+      resolvedBidId: "17785055-1111-4b4e-9fb0-5fc4cff0af3f",
+    }),
+  );
+
   await setTestResult("test-no-errors", checkNoErrors());
 
   console.info("Done checking results");
diff --git a/tests/test.html b/tests/test.html
index dfe213d..b8366f3 100644
--- a/tests/test.html
+++ b/tests/test.html
@@ -64,6 +64,10 @@
         <td>React Navigation</td>
         <td id="test-react-navigation">Pending</td>
       </tr>
+      <tr>
+        <td>Banner Products</td>
+        <td id="test-banner-products">Pending</td>
+      </tr>
       <tr>
         <td>No Errors</td>
         <td id="test-no-errors">Pending</td>
@@ -77,6 +81,9 @@
     <div data-ts-action="purchase" data-ts-items='[{"product": "product-id-purchase-1", "quantity":1, "price": 2399}, {"product": "product-id-purchase-2", "quantity": 2, "price": 399}]'>P</div>
     <div id="old-product" data-ts-product="product-id-attr-impression-1">P</div>
     <div id="hidden-product" data-ts-product="product-id-impression-hidden" style="visibility: none;">H</div>
+
+    <div id="banner" data-ts-resolved-bid="17785055-1111-4b4e-9fb0-5fc4cff0af3f">Banner</div>
+    <div id="banner-product" data-ts-product="additional-product-banner" data-ts-resolved-bid="inherit">P</div>
   </div>
   <div id="root"></div>
   <script>