Add impression tracking to VAST (Server-Side)

src/main/java/org/prebid/server/auction/ExchangeService.java

@@ -862,25 +862,21 @@ private static MetricName bidderErrorTypeToMetric(BidderError.Type errorType) {
     private Future<BidResponse> toBidResponse(List<BidderResponse> bidderResponses, BidRequest bidRequest,
                                               ExtRequestTargeting targeting, BidRequestCacheInfo cacheInfo,
                                               Account account, Timeout timeout, boolean debugEnabled) {
-        final Set<Bid> bids = bidderResponses.stream()
-                .map(BidderResponse::getSeatBid)
-                .filter(Objects::nonNull)
-                .map(BidderSeatBid::getBids)
-                .filter(Objects::nonNull)
-                .flatMap(Collection::stream)
-                .map(BidderBid::getBid)
-                .collect(Collectors.toSet());
-
-        return toBidsWithCacheIds(bids, bidRequest.getImp(), cacheInfo, account, timeout)
+        return toBidsWithCacheIds(bidderResponses, bidRequest.getImp(), cacheInfo, account, timeout)
                 .map(cacheResult -> bidResponseCreator.create(bidderResponses, bidRequest, targeting, cacheInfo,
                         cacheResult, account, debugEnabled));
     }
 
     /**
      * Corresponds cacheId (or null if not present) to each {@link Bid}.
      */
-    private Future<CacheServiceResult> toBidsWithCacheIds(Set<Bid> bids, List<Imp> imps, BidRequestCacheInfo cacheInfo,
-                                                          Account account, Timeout timeout) {
+    private Future<CacheServiceResult> toBidsWithCacheIds(List<BidderResponse> bidderResponses, List<Imp> imps,
+                                                          BidRequestCacheInfo cacheInfo, Account account,
+                                                          Timeout timeout) {
+        final Set<Bid> bids = bidderResponses.stream()
+                .flatMap(ExchangeService::getBids)
+                .collect(Collectors.toSet());
+
         final Future<CacheServiceResult> result;
 
         if (!cacheInfo.isDoCaching()) {
@@ -891,8 +887,20 @@ private Future<CacheServiceResult> toBidsWithCacheIds(Set<Bid> bids, List<Imp> i
                     .filter(bid -> bid.getPrice().compareTo(BigDecimal.ZERO) > 0)
                     .collect(Collectors.toList());
 
-            final CacheContext cacheContext = CacheContext.of(cacheInfo.isShouldCacheBids(),
-                    cacheInfo.getCacheBidsTtl(), cacheInfo.isShouldCacheVideoBids(), cacheInfo.getCacheVideoBidsTtl());
+            final boolean shouldCacheVideoBids = cacheInfo.isShouldCacheVideoBids();
+            final boolean eventsEnabled = Objects.equals(account.getEventsEnabled(), true);
+
+            final List<String> videoBidIdsToModify = shouldCacheVideoBids && eventsEnabled
+                    ? getVideoBidIdsToModify(bidderResponses, imps)
+                    : Collections.emptyList();
+
+            final CacheContext cacheContext = CacheContext.builder()
+                    .cacheBidsTtl(cacheInfo.getCacheBidsTtl())
+                    .cacheVideoBidsTtl(cacheInfo.getCacheVideoBidsTtl())
+                    .shouldCacheBids(cacheInfo.isShouldCacheBids())
+                    .shouldCacheVideoBids(shouldCacheVideoBids)
+                    .videoBidIdsToModify(videoBidIdsToModify)
+                    .build();
 
             result = cacheService.cacheBidsOpenrtb(bidsWithNonZeroPrice, imps, cacheContext, account, timeout)
                     .map(cacheResult -> addNotCachedBids(cacheResult, bids));
@@ -901,6 +909,32 @@ private Future<CacheServiceResult> toBidsWithCacheIds(Set<Bid> bids, List<Imp> i
         return result;
     }
 
+    private static Stream<Bid> getBids(BidderResponse bidderResponse) {
+        return Stream.of(bidderResponse)
+                .map(BidderResponse::getSeatBid)
+                .filter(Objects::nonNull)
+                .map(BidderSeatBid::getBids)
+                .filter(Objects::nonNull)
+                .flatMap(Collection::stream)
+                .map(BidderBid::getBid);
+    }
+
+    private List<String> getVideoBidIdsToModify(List<BidderResponse> bidderResponses, List<Imp> imps) {
+        return bidderResponses.stream()
+                .filter(bidderResponse -> bidderCatalog.isModifyingVastXmlAllowed(bidderResponse.getBidder()))
+                .flatMap(ExchangeService::getBids)
+                .filter(bid -> isVideoBid(bid, imps))
+                .map(Bid::getId)
+                .collect(Collectors.toList());
+    }
+
+    private static boolean isVideoBid(Bid bid, List<Imp> imps) {
+        return imps.stream()
+                .filter(imp -> imp.getId() != null && imp.getVideo() != null)
+                .map(Imp::getId)
+                .anyMatch(impId -> bid.getImpid().equals(impId));
+    }
+
     /**
      * Creates a map with {@link Bid} as a key and null as a value.
      */

src/main/java/org/prebid/server/bidder/BidderCatalog.java

@@ -56,6 +56,13 @@ public boolean isValidName(String name) {
         return bidderDepsMap.containsKey(name);
     }
 
+    /**
+     * Tells if given bidder allows to modify video's Vast XML.
+     */
+    public boolean isModifyingVastXmlAllowed(String name) {
+        return bidderDepsMap.containsKey(name) && bidderDepsMap.get(name).getBidderInfo().isModifyingVastXmlAllowed();
+    }
+
     /**
      * Tells if given name corresponds to any of the registered deprecated bidder's name.
      */

src/main/java/org/prebid/server/cache/CacheService.java

@@ -152,20 +152,23 @@ public Future<CacheServiceResult> cacheBidsOpenrtb(List<com.iab.openrtb.response
             final Map<String, Integer> impIdToTtl = new HashMap<>(imps.size());
             boolean impWithNoExpExists = false; // indicates at least one impression without expire presents
             final List<String> videoImpIds = new ArrayList<>();
+            final boolean shouldCacheVideoBids = cacheContext.isShouldCacheVideoBids();
             for (Imp imp : imps) {
-                impIdToTtl.put(imp.getId(), imp.getExp());
+                final String impId = imp.getId();
+                impIdToTtl.put(impId, imp.getExp());
                 impWithNoExpExists |= imp.getExp() == null;
-                if (cacheContext.isShouldCacheVideoBids() && imp.getId() != null && imp.getVideo() != null) {
-                    videoImpIds.add(imp.getId());
+                if (shouldCacheVideoBids && impId != null && imp.getVideo() != null) {
+                    videoImpIds.add(impId);
                 }
             }
 
             final List<CacheBid> cacheBids = getCacheBids(cacheContext.isShouldCacheBids(), bids, impIdToTtl,
                     impWithNoExpExists, cacheContext.getCacheBidsTtl(), account);
-            final List<CacheBid> videoCacheBids = getVideoCacheBids(cacheContext.isShouldCacheVideoBids(), bids,
+            final List<CacheBid> videoCacheBids = getVideoCacheBids(shouldCacheVideoBids, bids,
                     impIdToTtl, videoImpIds, impWithNoExpExists, cacheContext.getCacheVideoBidsTtl(), account);
 
-            result = doCacheOpenrtb(cacheBids, videoCacheBids, timeout);
+            result = doCacheOpenrtb(cacheBids, videoCacheBids, cacheContext.getVideoBidIdsToModify(), account.getId(),
+                    timeout);
         }
 
         return result;
@@ -238,10 +241,11 @@ private CacheBid toCacheBid(com.iab.openrtb.response.Bid bid, Map<String, Intege
      * <p>
      * The returned result will always have the number of elements equals to sum of sizes of bids and video bids.
      */
-    private Future<CacheServiceResult> doCacheOpenrtb(List<CacheBid> bids, List<CacheBid> videoBids, Timeout timeout) {
+    private Future<CacheServiceResult> doCacheOpenrtb(List<CacheBid> bids, List<CacheBid> videoBids,
+                                                      List<String> bidIdsToModify, String accountId, Timeout timeout) {
         final List<PutObject> putObjects = Stream.concat(
                 bids.stream().map(CacheService::createJsonPutObjectOpenrtb),
-                videoBids.stream().map(CacheService::createXmlPutObjectOpenrtb))
+                videoBids.stream().map(cacheBid -> createXmlPutObjectOpenrtb(cacheBid, bidIdsToModify, accountId)))
                 .collect(Collectors.toList());
 
         if (putObjects.isEmpty()) {
@@ -326,16 +330,47 @@ private static PutObject createJsonPutObjectOpenrtb(CacheBid cacheBid) {
     /**
      * Makes XML type {@link PutObject} from {@link com.iab.openrtb.response.Bid}. Used for OpenRTB auction request.
      */
-    private static PutObject createXmlPutObjectOpenrtb(CacheBid cacheBid) {
-        if (cacheBid.getBid().getAdm() == null) {
-            return PutObject.of("xml", new TextNode("<VAST version=\"3.0\"><Ad><Wrapper>"
+    private static PutObject createXmlPutObjectOpenrtb(CacheBid cacheBid, List<String> bidIdsToModify,
+                                                       String accountId) {
+        final com.iab.openrtb.response.Bid bid = cacheBid.getBid();
+        String stringValue;
+        if (bid.getAdm() == null) {
+            stringValue = "<VAST version=\"3.0\"><Ad><Wrapper>"
                     + "<AdSystem>prebid.org wrapper</AdSystem>"
-                    + "<VASTAdTagURI><![CDATA[" + cacheBid.getBid().getNurl() + "]]></VASTAdTagURI>"
+                    + "<VASTAdTagURI><![CDATA[" + bid.getNurl() + "]]></VASTAdTagURI>"
                     + "<Impression></Impression><Creatives></Creatives>"
-                    + "</Wrapper></Ad></VAST>"), cacheBid.getTtl());
+                    + "</Wrapper></Ad></VAST>";
         } else {
-            return PutObject.of("xml", new TextNode(cacheBid.getBid().getAdm()), cacheBid.getTtl());
+            stringValue = bid.getAdm();
         }
+
+        final String bidId = bid.getId();
+        if (CollectionUtils.isNotEmpty(bidIdsToModify) && bidIdsToModify.contains(bidId)) {
+            stringValue = modifyVastXml(stringValue, bidId, accountId);
+        }
+
+        return PutObject.of("xml", new TextNode(stringValue), cacheBid.getTtl());
+    }
+
+    private static String modifyVastXml(String stringValue, String bidId, String accountId) {
+        final String closeTag = "</Impression>";
+        final int closeTagIndex = stringValue.indexOf(closeTag);
+
+        // no impression tag - pass it as it is
+        if (closeTagIndex == -1) {
+            return stringValue;
+        }
+
+        final String impressionUrl = String.format("https://prebid-server.rubiconproject.com/event?t=imp&b=%s&f=b&a=%s",
+                bidId, accountId);
+        final String openTag = "<Impression>";
+
+        // empty impression tag - just insert the link
+        if (closeTagIndex - stringValue.indexOf(openTag) == openTag.length()) {
+            return stringValue.replaceFirst(openTag, openTag + impressionUrl);
+        }
+
+        return stringValue.replaceFirst(closeTag, closeTag + "\n" + openTag + impressionUrl + closeTag);
     }
 
     /**

src/main/java/org/prebid/server/cache/model/CacheContext.java

@@ -1,12 +1,14 @@
 package org.prebid.server.cache.model;
 
-import lombok.AllArgsConstructor;
+import lombok.Builder;
 import lombok.Value;
 
+import java.util.List;
+
 /**
  * Holds the state needed to perform caching response bids.
  */
-@AllArgsConstructor(staticName = "of")
+@Builder
 @Value
 public class CacheContext {
 
@@ -17,4 +19,6 @@ public class CacheContext {
     boolean shouldCacheVideoBids;
 
     Integer cacheVideoBidsTtl;
+
+    List<String> videoBidIdsToModify;
 }

src/main/java/org/prebid/server/proto/response/BidderInfo.java

@@ -10,6 +10,8 @@ public class BidderInfo {
 
     boolean enabled;
 
+    boolean modifyingVastXmlAllowed;
+
     MaintainerInfo maintainer;
 
     CapabilitiesInfo capabilities;
@@ -18,15 +20,15 @@ public class BidderInfo {
 
     GdprInfo gdpr;
 
-    public static BidderInfo create(boolean enabled, String maintainerEmail, List<String> appMediaTypes,
-                                    List<String> siteMediaTypes, List<String> supportedVendors,
-                                    int vendorId, boolean enforceGdpr) {
+    public static BidderInfo create(boolean enabled, boolean modifyingVastXmlAllowed, String maintainerEmail,
+                                    List<String> appMediaTypes, List<String> siteMediaTypes,
+                                    List<String> supportedVendors, int vendorId, boolean enforceGdpr) {
         final MaintainerInfo maintainer = new MaintainerInfo(maintainerEmail);
         final CapabilitiesInfo capabilities = new CapabilitiesInfo(platformInfo(appMediaTypes),
                 platformInfo(siteMediaTypes));
         final GdprInfo gdpr = new GdprInfo(vendorId, enforceGdpr);
 
-        return new BidderInfo(enabled, maintainer, capabilities, supportedVendors, gdpr);
+        return new BidderInfo(enabled, modifyingVastXmlAllowed, maintainer, capabilities, supportedVendors, gdpr);
     }
 
     private static PlatformInfo platformInfo(List<String> mediaTypes) {

src/main/java/org/prebid/server/spring/config/bidder/model/BidderConfigurationProperties.java

@@ -16,6 +16,8 @@ public class BidderConfigurationProperties {
     @NotNull
     private Boolean enabled;
 
+    private boolean modifyingVastXmlAllowed;
+
     @NotBlank
     private String endpoint;
 

src/main/java/org/prebid/server/spring/config/bidder/util/BidderInfoCreator.java

@@ -14,6 +14,7 @@ public static BidderInfo create(BidderConfigurationProperties configurationPrope
         final MetaInfo metaInfo = configurationProperties.getMetaInfo();
         return BidderInfo.create(
                 configurationProperties.getEnabled(),
+                configurationProperties.isModifyingVastXmlAllowed(),
                 metaInfo.getMaintainerEmail(),
                 metaInfo.getAppMediaTypes(),
                 metaInfo.getSiteMediaTypes(),

src/test/java/org/prebid/server/auction/ExchangeServiceTest.java

@@ -15,6 +15,7 @@
 import com.iab.openrtb.request.Regs;
 import com.iab.openrtb.request.Site;
 import com.iab.openrtb.request.User;
+import com.iab.openrtb.request.Video;
 import com.iab.openrtb.response.Bid;
 import com.iab.openrtb.response.BidResponse;
 import com.iab.openrtb.response.SeatBid;
@@ -62,6 +63,7 @@
 import org.prebid.server.proto.openrtb.ext.request.ExtRequestPrebid;
 import org.prebid.server.proto.openrtb.ext.request.ExtRequestPrebidCache;
 import org.prebid.server.proto.openrtb.ext.request.ExtRequestPrebidCacheBids;
+import org.prebid.server.proto.openrtb.ext.request.ExtRequestPrebidCacheVastxml;
 import org.prebid.server.proto.openrtb.ext.request.ExtRequestPrebidData;
 import org.prebid.server.proto.openrtb.ext.request.ExtRequestTargeting;
 import org.prebid.server.proto.openrtb.ext.request.ExtSite;
@@ -1048,10 +1050,44 @@ public void shouldRequestCacheServiceWithExpectedArguments() {
         // then
         verify(cacheService).cacheBidsOpenrtb(
                 argThat(t -> t.containsAll(asList(bid1, bid2))), eq(asList(imp1, imp2)),
-                eq(CacheContext.of(true, null, false, null)),
+                eq(CacheContext.builder().shouldCacheBids(true).videoBidIdsToModify(emptyList()).build()),
                 eq(Account.builder().id("accountId").eventsEnabled(false).build()), eq(timeout));
     }
 
+    @Test
+    public void shouldRequestCacheServiceWithVideoBidsToModifyWhenEventsEnabledAndForBidderThatAllowsModifyVastXml() {
+        // given
+        final Bid bid1 = Bid.builder().id("bidId1").impid("impId1").price(BigDecimal.valueOf(5.67)).build();
+        final Bid bid2 = Bid.builder().id("bidId2").impid("impId2").price(BigDecimal.valueOf(7.19)).build();
+        givenBidder("bidder1", mock(Bidder.class), givenSeatBid(singletonList(givenBid(bid1))));
+        givenBidder("bidder2", mock(Bidder.class), givenSeatBid(singletonList(givenBid(bid2))));
+
+        given(bidderCatalog.isModifyingVastXmlAllowed(eq("bidder1"))).willReturn(true, false);
+
+        // imp ids are not really used for matching, included them here for clarity
+        final Imp imp1 = givenImp(singletonMap("bidder1", 1),
+                builder -> builder.id("impId1").video(Video.builder().build()));
+        final Imp imp2 = givenImp(singletonMap("bidder2", 2),
+                builder -> builder.id("impId2").video(Video.builder().build()));
+        final BidRequest bidRequest = givenBidRequest(asList(imp1, imp2),
+                builder -> builder.ext(mapper.valueToTree(ExtBidRequest.of(ExtRequestPrebid.builder()
+                        .targeting(givenTargeting())
+                        .cache(ExtRequestPrebidCache.of(ExtRequestPrebidCacheBids.of(null, null),
+                                ExtRequestPrebidCacheVastxml.of(null, true)))
+                        .build()))));
+
+        // when
+        exchangeService.holdAuction(givenRequestContext(bidRequest,
+                Account.builder().id("accountId").eventsEnabled(true).build()));
+
+        // then
+        verify(cacheService).cacheBidsOpenrtb(
+                argThat(t -> t.containsAll(asList(bid1, bid2))), eq(asList(imp1, imp2)),
+                eq(CacheContext.builder().shouldCacheBids(true).shouldCacheVideoBids(true)
+                        .videoBidIdsToModify(singletonList("bidId1")).build()),
+                eq(Account.builder().id("accountId").eventsEnabled(true).build()), eq(timeout));
+    }
+
     @Test
     public void shouldCallCacheServiceEvenRoundedCpmIsZero() {
         // given
@@ -1071,7 +1107,7 @@ public void shouldCallCacheServiceEvenRoundedCpmIsZero() {
 
         // then
         verify(cacheService).cacheBidsOpenrtb(argThat(bids -> bids.contains(bid1)), eq(singletonList(imp1)),
-                eq(CacheContext.of(true, null, false, null)),
+                eq(CacheContext.builder().shouldCacheBids(true).videoBidIdsToModify(emptyList()).build()),
                 eq(Account.builder().id("accountId").eventsEnabled(false).build()), eq(timeout));
     }
 
@@ -1549,7 +1585,7 @@ private static <K, V> Map<K, V> doubleMap(K key1, V value1, K key2, V value2) {
     }
 
     private static BidderInfo givenBidderInfo(int gdprVendorId, boolean enforceGdpr) {
-        return new BidderInfo(true, null, null, null, new BidderInfo.GdprInfo(gdprVendorId, enforceGdpr));
+        return new BidderInfo(true, false, null, null, null, new BidderInfo.GdprInfo(gdprVendorId, enforceGdpr));
     }
 
     private static ExtRequestTargeting givenTargeting() {

src/test/java/org/prebid/server/auction/PrivacyEnforcementServiceTest.java

@@ -657,7 +657,7 @@ private static <T> Imp givenImp(T ext, Function<Imp.ImpBuilder, Imp.ImpBuilder>
     }
 
     private static BidderInfo givenBidderInfo(int gdprVendorId, boolean enforceGdpr) {
-        return new BidderInfo(true, null, null, null, new BidderInfo.GdprInfo(gdprVendorId, enforceGdpr));
+        return new BidderInfo(true, false, null, null, null,
+                new BidderInfo.GdprInfo(gdprVendorId, enforceGdpr));
     }
 }
-

src/test/java/org/prebid/server/bidder/BidderCatalogTest.java

@@ -139,7 +139,7 @@ public void nameByAliasShouldReturnBidderName() {
     @Test
     public void metaInfoByNameShouldReturnMetaInfoForKnownBidder() {
         // given
-        final BidderInfo bidderInfo = BidderInfo.create(true, "test@email.com",
+        final BidderInfo bidderInfo = BidderInfo.create(true, false, "test@email.com",
                 singletonList("banner"), singletonList("video"), null, 99, true);
 
         bidderDeps = BidderDeps.builder()