Merge pull request #3 from SemanticSugar/cache-xid-js-null-response

Cache XID.js null response using the Prebid.js cookie

modules/nextrollIdSystem.js

@@ -6,7 +6,15 @@
  */
 
 import {submodule} from '../src/hook';
-import * as utils from '../src/utils'
+import * as utils from '../src/utils';
+import { getStorageManager } from '../src/storageManager.js';
+const storage = getStorageManager();
+
+const NEXTROLL_ID_LS_KEY = "nextroll_id_ls_key";
+const NEXTROLL_ID_TEST_KEY = NEXTROLL_ID_LS_KEY + "_test";
+const NEXTROLL_ID_DATE_KEY = NEXTROLL_ID_LS_KEY + "_set_date";
+const DEFAULT_MISSING_VALUE = 'undefined';
+const DEFAULT_ATTEMPT_FREQUENCY_MS = 1000 * 60 * 60 * 2; // 2hrs
 
 function loadRetrieval() {
 // v3.6
@@ -32,37 +40,88 @@ function isValidUA() {
          (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1))
 }
 
+function removeAttemptTimestamp() {
+  if (storage.hasLocalStorage()) {
+    storage.removeDataFromLocalStorage(NEXTROLL_ID_DATE_KEY);
+  }
+}
+
+// Sets unsuccesful attempt timestamp
+// Note: assumes window has localstorage enabled.
+function setAttemptTimestamp() {
+  const date = (new Date()).getTime();
+  storage.setDataInLocalStorage(NEXTROLL_ID_DATE_KEY, date);
+}
+
+function getXIDCallback(cb) {
+  return (result) => {
+    if (isValidResult(result)) {
+      cb(result);
+      removeAttemptTimestamp()
+      return;
+    }
+    // No valid id, and no localstorage
+    if (!storage.hasLocalStorage()) {
+      cb(DEFAULT_MISSING_VALUE);
+      return;
+    }
+
+    // localstorage and no valid id
+    setAttemptTimestamp();
+  }
+}
+
+function shouldAttemptRetrieval(attemptFrequencyMS) {
+  if (attemptFrequencyMS === undefined ||
+      typeof attemptFrequencyMS !== "number") {
+    attemptFrequencyMS = DEFAULT_ATTEMPT_FREQUENCY_MS;
+  }
+
+  if (!storage.hasLocalStorage())  {
+    // It means we're using prebid cache for unsuccesful attempts.
+    return true;
+  }
+
+  const storedDate = storage.getDataFromLocalStorage(NEXTROLL_ID_DATE_KEY);
+  if (storedDate === null) {
+    return true;
+  }
+
+  const currentDate = (new Date).getTime();
+  const storedDateNum = parseInt(storedDate);
+
+  if (currentDate - storedDateNum > attemptFrequencyMS) {
+    return true
+  }
+
+  return false;
+}
+
+function getFetchIdCallback(metadata) {
+  return (cb) => {
+    loadRetrieval();
+    const xidCB = getXIDCallback(cb);
+    window.RetrieveAdID(xidCB, xidCB, metadata);
+  }
+}
+
 function fetchId(configParams, consentData, currentStoredId) {
   if (!isValidConfig(configParams)) {
     utils.logWarn("Partner ID - nextrollId submodule requires a partner ID");
     return;
   }
 
-  if(!isValidUA()) {
+  if (!isValidUA() ||
+      !shouldAttemptRetrieval(configParams.attempt_frequency_ms)) {
     return;
   }
 
-  loadRetrieval();
-
   let metadata = {
     'PID': configParams.partner_id,
     'app': 'nextroll_id_module'
   }
 
-  const callback = function (cb) {
-    window.RetrieveAdID(
-        function (result) {
-          if (isValidResult(result))
-            cb(result);
-        },
-        function (result) {
-          if (isValidResult(result))
-            cb(result);
-        },
-        metadata
-    );
-  };
-
+  const callback = getFetchIdCallback(metadata);
   return { callback };
 };
 
@@ -80,7 +139,10 @@ export const nextrollIdSubmodule = {
    * @return {(Object|undefined}
    */
   decode(value) {
-    return (value && typeof value === 'string') ? { 'nextroll': value } : undefined;
+    if (value && typeof value === 'string' && value !== DEFAULT_MISSING_VALUE)  {
+      return { 'nextroll': value };
+    }
+    return undefined;
   },
 
   /**