From 9a29770a24672e4f2e624152d77952689abaff14 Mon Sep 17 00:00:00 2001
From: saurabh-narkhede <saurabh.narkhede@pubmatic.com>
Date: Wed, 28 Feb 2024 10:26:37 +0000
Subject: [PATCH 1/2] dchain support

---
 dchain/dchain.go     | 59 ++++++++++++++++++++++++++++++++++++++++++++
 exchange/exchange.go |  5 ++++
 2 files changed, 64 insertions(+)
 create mode 100644 dchain/dchain.go

diff --git a/dchain/dchain.go b/dchain/dchain.go
new file mode 100644
index 00000000000..03b608e203e
--- /dev/null
+++ b/dchain/dchain.go
@@ -0,0 +1,59 @@
+package dchain
+
+import (
+	"encoding/json"
+	"strconv"
+
+	"github.com/prebid/prebid-server/v2/openrtb_ext"
+)
+
+type Dchain struct {
+	Ver      string          `json:"ver,omitempty"`
+	Complete int             `json:"complete,omitempty"`
+	Nodes    []DchainNodes   `json:"nodes,omitempty"`
+	Ext      json.RawMessage `json:"ext,omitempty"`
+}
+
+type DchainNodes struct {
+	Asi    string          `json:"asi,omitempty"`
+	Bsid   string          `json:"bsid,omitempty"`
+	Rid    string          `json:"rid,omitempty"`
+	Name   string          `json:"name,omitempty"`
+	Domain string          `json:"domain,omitempty"`
+	Ext    json.RawMessage `json:"ext,omitempty"`
+}
+
+func IsValidDchain(dchain Dchain) bool {
+	if dchain.Complete != 0 && dchain.Complete != 1 {
+		return false
+	}
+	if dchain.Nodes == nil || len(dchain.Nodes) == 0 {
+		return false
+	}
+	return true
+}
+
+func AddDchainNode(prebidMeta *openrtb_ext.ExtBidPrebidMeta) {
+	var dchain Dchain
+	if err := json.Unmarshal(prebidMeta.DChain, &dchain); err == nil && IsValidDchain(dchain) {
+		dchain.Nodes = append(dchain.Nodes,
+			DchainNodes{Asi: prebidMeta.AdapterCode},
+		)
+		prebidMeta.DChain, _ = json.Marshal(dchain)
+		return
+	}
+	basicDchain := Dchain{
+		Ver:      "1.0",
+		Complete: 0,
+		Nodes:    []DchainNodes{},
+	}
+
+	if prebidMeta.NetworkID != 0 && prebidMeta.NetworkName != "" {
+		basicDchain.Nodes = append(basicDchain.Nodes,
+			DchainNodes{Name: prebidMeta.NetworkName, Bsid: strconv.Itoa(prebidMeta.NetworkID)},
+		)
+	}
+
+	basicDchain.Nodes = append(basicDchain.Nodes, DchainNodes{Name: prebidMeta.AdapterCode})
+	prebidMeta.DChain, _ = json.Marshal(basicDchain)
+}
diff --git a/exchange/exchange.go b/exchange/exchange.go
index 003ce559dc2..724d91755a1 100644
--- a/exchange/exchange.go
+++ b/exchange/exchange.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/prebid/prebid-server/v2/dchain"
 	"github.com/prebid/prebid-server/v2/privacy"
 
 	"github.com/prebid/prebid-server/v2/adapters"
@@ -1334,6 +1335,10 @@ func makeBidExtJSON(ext json.RawMessage, prebid *openrtb_ext.ExtBidPrebid, impEx
 		prebid.Meta = &openrtb_ext.ExtBidPrebidMeta{}
 	}
 
+	if prebid.Meta.DChain != nil {
+		dchain.AddDchainNode(prebid.Meta)
+	}
+
 	prebid.Meta.AdapterCode = adapter.String()
 
 	// ext.prebid.storedrequestattributes and ext.prebid.passthrough

From 439bdf19fa1489358cc51aca5bfc384a570c1cc6 Mon Sep 17 00:00:00 2001
From: saurabh-narkhede <saurabh.narkhede@pubmatic.com>
Date: Tue, 5 Mar 2024 06:22:00 +0000
Subject: [PATCH 2/2] initial commit dchain support

---
 adapters/pubmatic/pubmatic.go | 6 ++++++
 exchange/exchange.go          | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/adapters/pubmatic/pubmatic.go b/adapters/pubmatic/pubmatic.go
index 9876041ec4e..6d5241aad18 100644
--- a/adapters/pubmatic/pubmatic.go
+++ b/adapters/pubmatic/pubmatic.go
@@ -450,6 +450,12 @@ func (a *PubmaticAdapter) MakeBids(internalRequest *openrtb2.BidRequest, externa
 				BidVideo: &openrtb_ext.ExtBidPrebidVideo{},
 			}
 
+			if dchain, _, _, err := jsonparser.Get(bid.Ext, "dchain"); err == nil && len(dchain) > 0 {
+				typedBid.BidMeta = &openrtb_ext.ExtBidPrebidMeta{
+					DChain: dchain,
+				}
+			}
+
 			var bidExt *pubmaticBidExt
 			err := json.Unmarshal(bid.Ext, &bidExt)
 			if err != nil {
diff --git a/exchange/exchange.go b/exchange/exchange.go
index 7aa8526c955..402a47546c7 100644
--- a/exchange/exchange.go
+++ b/exchange/exchange.go
@@ -1346,12 +1346,12 @@ func makeBidExtJSON(ext json.RawMessage, prebid *openrtb_ext.ExtBidPrebid, impEx
 		prebid.Meta = &openrtb_ext.ExtBidPrebidMeta{}
 	}
 
+	prebid.Meta.AdapterCode = adapter.String()
+
 	if prebid.Meta.DChain != nil {
 		dchain.AddDchainNode(prebid.Meta)
 	}
 
-	prebid.Meta.AdapterCode = adapter.String()
-
 	// ext.prebid.storedrequestattributes and ext.prebid.passthrough
 	if impExtInfo, ok := impExtInfoMap[impId]; ok {
 		prebid.Passthrough = impExtInfoMap[impId].Passthrough