Core: allow vast xml without using cache

src/video.ts

@@ -131,8 +131,12 @@ declare module './hook' {
 export const checkVideoBidSetup = hook('sync', function(bid: VideoBid, adUnit, videoMediaType, context, useCacheKey) {
   if (videoMediaType && (useCacheKey || context !== OUTSTREAM)) {
     // xml-only video bids require a prebid cache url
-    const { url, useLocal } = config.getConfig('cache') || {};
+    const { url, useLocal, allowVastXmlOnly } = config.getConfig('cache') || {};
     if ((!url && !useLocal) && bid.vastXml && !bid.vastUrl) {
+      if (allowVastXmlOnly === true) {
+        logWarn(`This bid contains only vastXml, and caching is disabled. Proceeding because cache.allowVastXmlOnly is enabled.`);
+        return true;
+      }
       logError(`
         This bid contains only vastXml and will not work when a prebid cache url is not specified.
         Try enabling either prebid cache with ${getGlobalVarName()}.setConfig({ cache: {url: "..."} });

src/videoCache.ts

@@ -78,6 +78,10 @@ export interface CacheConfig {
    * Flag determining whether to locally save VAST XML as a blob
    */
   useLocal?: boolean;
+  /**
+   * When true, allows VAST XML-only bids to pass even without cache.url or cache.useLocal.
+   */
+  allowVastXmlOnly?: boolean;
   /**
    * Timeout (in milliseconds) for network requests to the cache
    */

test/spec/video_spec.js

@@ -3,6 +3,7 @@ import { hook } from '../../src/hook.js';
 import { stubAuctionIndex } from '../helpers/indexStub.js';
 import * as utils from '../../src/utils.js';
 import { syncOrtb2, validateOrtbFields } from '../../src/prebid.js';
+import { config } from 'src/config.js';
 
 describe('video.js', function () {
   let sandbox;
@@ -19,6 +20,7 @@ describe('video.js', function () {
 
   afterEach(() => {
     utilsMock.restore();
+    config.resetConfig();
     sandbox.restore();
   });
 
@@ -284,6 +286,21 @@ describe('video.js', function () {
       expect(valid).to.equal(false);
     });
 
+    it('validates vastXml-only bids when cache.allowVastXmlOnly is enabled', function () {
+      utilsMock.expects('logWarn').once();
+      utilsMock.expects('logError').never();
+      config.setConfig({ cache: { allowVastXmlOnly: true } });
+
+      const adUnits = [{
+        adUnitId: 'au',
+        bidder: 'vastOnlyVideoBidder',
+        mediaTypes: { video: {} },
+      }];
+
+      const valid = isValidVideoBid({ adUnitId: 'au', vastXml: '<xml>vast</xml>' }, { index: stubAuctionIndex({ adUnits }) });
+      expect(valid).to.equal(true);
+    });
+
     it('validates valid outstream bids', function () {
       const bid = {
         adUnitId: 'au',