Permutive RTD: support msft bidder custom cohorts via configurable storage read

Add a `bidders` config to the Permutive RTD module that allows configuring
per-bidder custom cohort storage sources. This enables the msft bidder
(Microsoft/Xandr) to read custom cohorts from the same localStorage key
(`_papns`) used by appnexus, resolving an issue where publishers migrating
from appnexus to msft lost custom cohort targeting.

Refactors `updateOrtbConfig` to receive resolved `customCohortsData` directly
instead of performing the lookup internally, keeping segment resolution
centralized in `setBidderRtb`.

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

Author: AntonioGargaro

modules/permutiveRtdProvider.js

@@ -91,6 +91,11 @@ export function getModuleConfig(customModuleConfig) {
       acBidders: [],
       overwrites: {},
       enforceVendorConsent: false,
+      bidders: {
+        msft: {
+          customCohortsFrom: { type: 'ls', key: '_papns' }
+        },
+      },
     },
   },
   permutiveModuleConfig,
@@ -108,13 +113,15 @@ export function setBidderRtb (bidderOrtb2, moduleConfig, segmentData) {
   const acBidders = deepAccess(moduleConfig, 'params.acBidders')
   const maxSegs = deepAccess(moduleConfig, 'params.maxSegs')
   const transformationConfigs = deepAccess(moduleConfig, 'params.transformations') || []
+  const biddersConfig = deepAccess(moduleConfig, 'params.bidders') || {}
 
   const ssps = segmentData?.ssp?.ssps ?? []
   const sspCohorts = segmentData?.ssp?.cohorts ?? []
   const topics = segmentData?.topics ?? {}
 
   const bidders = new Set([...acBidders, ...ssps])
   bidders.forEach(function (bidder) {
+    const bidderConfig = biddersConfig[bidder] || {};
     const currConfig = { ortb2: bidderOrtb2[bidder] || {} }
 
     let cohorts = []
@@ -129,11 +136,29 @@ export function setBidderRtb (bidderOrtb2, moduleConfig, segmentData) {
       cohorts = [...new Set([...cohorts, ...sspCohorts])].slice(0, maxSegs)
     }
 
-    const nextConfig = updateOrtbConfig(bidder, currConfig, cohorts, sspCohorts, topics, transformationConfigs, segmentData)
+    const customCohortsData = getCustomCohortsData(bidderConfig, bidder, segmentData, maxSegs)
+
+    const nextConfig = updateOrtbConfig(bidder, currConfig, cohorts, sspCohorts, topics, transformationConfigs, customCohortsData)
     bidderOrtb2[bidder] = nextConfig.ortb2
   })
 }
 
+/**
+ * Resolves custom cohorts data for a bidder, reading from localStorage if configured.
+ * @param {Object} bidderCfg - Bidder-specific configuration from params.bidders
+ * @param {string} bidder - The bidder identifier
+ * @param {Object} segmentData - Segment data grouped by bidder or type
+ * @param {number} maxSegs - Maximum number of segments
+ * @return {string[]} Custom cohort IDs
+ */
+function getCustomCohortsData (bidderCfg, bidder, segmentData, maxSegs) {
+  const customCohortsFrom = bidderCfg?.customCohortsFrom
+  if (customCohortsFrom?.type === 'ls' && customCohortsFrom?.key) {
+    return makeSafe(() => readSegments(customCohortsFrom.key, []).map(String).slice(0, maxSegs)) || []
+  }
+  return deepAccess(segmentData, bidder) || []
+}
+
 /**
  * Updates `user.data` object in existing bidder config with Permutive segments
  * @param {string} bidder - The bidder identifier
@@ -143,14 +168,12 @@ export function setBidderRtb (bidderOrtb2, moduleConfig, segmentData) {
  * @param {Object} topics - Privacy Sandbox Topics, keyed by IAB taxonomy version (600, 601, etc.)
  * @param {Object[]} transformationConfigs - array of objects with `id` and `config` properties, used to determine
  *                                           the transformations on user data to include the ORTB2 object
- * @param {Object} segmentData - The segments available for targeting
+ * @param {string[]} customCohortsData - Custom cohort IDs for this bidder
  * @return {Object} Merged ortb2 object
  */
-function updateOrtbConfig(bidder, currConfig, segmentIDs, sspSegmentIDs, topics, transformationConfigs, segmentData) {
+function updateOrtbConfig(bidder, currConfig, segmentIDs, sspSegmentIDs, topics, transformationConfigs, customCohortsData) {
   logger.logInfo(`Current ortb2 config`, { bidder, config: currConfig })
 
-  const customCohortsData = deepAccess(segmentData, bidder) || []
-
   const name = 'permutive.com'
 
   const permutiveUserData = {

test/spec/modules/permutiveCombined_spec.js

@@ -128,6 +128,11 @@ describe('permutiveRtdProvider', function () {
         acBidders: [],
         overwrites: {},
         enforceVendorConsent: false,
+        bidders: {
+          msft: {
+            customCohortsFrom: { type: 'ls', key: '_papns' }
+          },
+        },
       },
     })
 
@@ -689,6 +694,66 @@ describe('permutiveRtdProvider', function () {
         })
       })
     })
+
+    describe('bidders config with customCohortsFrom', function () {
+      it('should read custom cohorts from localStorage for msft bidder using customCohortsFrom config', function () {
+        const segmentsData = transformedTargeting()
+        const expectedAppnexusCohorts = segmentsData.appnexus
+
+        const moduleConfig = {
+          name: 'permutive',
+          waitForIt: true,
+          params: {
+            acBidders: ['msft'],
+            maxSegs: 500,
+            bidders: {
+              msft: {
+                customCohortsFrom: { type: 'ls', key: '_papns' }
+              }
+            }
+          }
+        }
+        const bidderConfig = {}
+
+        setBidderRtb(bidderConfig, moduleConfig, segmentsData)
+
+        expect(bidderConfig['msft'].user.data).to.deep.include.members([
+          {
+            name: 'permutive',
+            segment: expectedAppnexusCohorts.map(id => ({ id })),
+          },
+        ])
+
+        expectedAppnexusCohorts.forEach(id => {
+          expect(bidderConfig['msft'].user.keywords).to.include(`permutive=${id}`)
+        })
+      })
+
+      it('should fall back to segmentData lookup when customCohortsFrom is not configured', function () {
+        const segmentsData = transformedTargeting()
+
+        const moduleConfig = {
+          name: 'permutive',
+          waitForIt: true,
+          params: {
+            acBidders: ['appnexus'],
+            maxSegs: 500,
+            bidders: {}
+          }
+        }
+        const bidderConfig = {}
+
+        setBidderRtb(bidderConfig, moduleConfig, segmentsData)
+
+        const expectedAppnexusCohorts = segmentsData.appnexus
+        expect(bidderConfig['appnexus'].user.data).to.deep.include.members([
+          {
+            name: 'permutive',
+            segment: expectedAppnexusCohorts.map(id => ({ id })),
+          },
+        ])
+      })
+    })
   })
 
   describe('Getting segments', function () {