DSA: Bid response adrender, behalf & paid validations (#3523)

dsa/validate.go

@@ -1,51 +1,103 @@
 package dsa
 
 import (
+	"errors"
+
 	"github.com/prebid/prebid-server/v2/exchange/entities"
 	"github.com/prebid/prebid-server/v2/openrtb_ext"
+	"github.com/prebid/prebid-server/v2/util/jsonutil"
+)
 
-	"github.com/buger/jsonparser"
+// Required values representing whether a DSA object is required
+const (
+	Required               int8 = 2 // bid responses without DSA object will not be accepted
+	RequiredOnlinePlatform int8 = 3 // bid responses without DSA object will not be accepted, Publisher is Online Platform
 )
 
+// PubRender values representing publisher rendering intentions
 const (
-	// Required - bid responses without DSA object will not be accepted
-	Required = 2
-	// RequiredOnlinePlatform - bid responses without DSA object will not be accepted, Publisher is an Online Platform
-	RequiredOnlinePlatform = 3
+	PubRenderCannotRender int8 = 0 // publisher can't render
+	PubRenderWillRender   int8 = 2 // publisher will render
+)
+
+// AdRender values representing buyer/advertiser rendering intentions
+const (
+	AdRenderWillRender int8 = 1 // buyer/advertiser will render
+)
+
+var (
+	ErrDsaMissing        = errors.New("DSA object missing when required")
+	ErrBehalfTooLong     = errors.New("DSA behalf exceeds limit of 100 chars")
+	ErrPaidTooLong       = errors.New("DSA paid exceeds limit of 100 chars")
+	ErrNeitherWillRender = errors.New("DSA publisher and buyer both signal will not render")
+	ErrBothWillRender    = errors.New("DSA publisher and buyer both signal will render")
+)
+
+const (
+	behalfMaxLength = 100
+	paidMaxLength   = 100
 )
 
 // Validate determines whether a given bid is valid from a DSA perspective.
 // A bid is considered valid unless the bid request indicates that a DSA object is required
-// in bid responses and the object happens to be missing from the specified bid.
-func Validate(req *openrtb_ext.RequestWrapper, bid *entities.PbsOrtbBid) (valid bool) {
-	if !dsaRequired(req) {
-		return true
+// in bid responses and the object happens to be missing from the specified bid, or if the bid
+// DSA object contents are invalid
+func Validate(req *openrtb_ext.RequestWrapper, bid *entities.PbsOrtbBid) error {
+	reqDSA := getReqDSA(req)
+	bidDSA := getBidDSA(bid)
+
+	if dsaRequired(reqDSA) && bidDSA == nil {
+		return ErrDsaMissing
 	}
-	if bid == nil || bid.Bid == nil {
-		return false
+	if bidDSA == nil {
+		return nil
+	}
+	if len(bidDSA.Behalf) > behalfMaxLength {
+		return ErrBehalfTooLong
 	}
-	_, dataType, _, err := jsonparser.Get(bid.Bid.Ext, "dsa")
-	if dataType == jsonparser.Object && err == nil {
-		return true
-	} else if err != nil && err != jsonparser.KeyPathNotFoundError {
-		return true
+	if len(bidDSA.Paid) > paidMaxLength {
+		return ErrPaidTooLong
 	}
-	return false
+	if reqDSA != nil && reqDSA.PubRender != nil && bidDSA.AdRender != nil {
+		if *reqDSA.PubRender == PubRenderCannotRender && *bidDSA.AdRender != AdRenderWillRender {
+			return ErrNeitherWillRender
+		}
+		if *reqDSA.PubRender == PubRenderWillRender && *bidDSA.AdRender == AdRenderWillRender {
+			return ErrBothWillRender
+		}
+	}
+	return nil
 }
 
 // dsaRequired examines the bid request to determine if the dsarequired field indicates
 // that bid responses include a dsa object
-func dsaRequired(req *openrtb_ext.RequestWrapper) bool {
+func dsaRequired(dsa *openrtb_ext.ExtRegsDSA) bool {
+	if dsa == nil || dsa.Required == nil {
+		return false
+	}
+	return *dsa.Required == Required || *dsa.Required == RequiredOnlinePlatform
+}
+
+// getReqDSA retrieves the DSA object from the request
+func getReqDSA(req *openrtb_ext.RequestWrapper) *openrtb_ext.ExtRegsDSA {
+	if req == nil {
+		return nil
+	}
 	regExt, err := req.GetRegExt()
 	if regExt == nil || err != nil {
-		return false
+		return nil
 	}
-	regsDSA := regExt.GetDSA()
-	if regsDSA == nil {
-		return false
+	return regExt.GetDSA()
+}
+
+// getBidDSA retrieves the DSA object from the bid
+func getBidDSA(bid *entities.PbsOrtbBid) *openrtb_ext.ExtBidDSA {
+	if bid == nil || bid.Bid == nil {
+		return nil
 	}
-	if regsDSA.Required == Required || regsDSA.Required == RequiredOnlinePlatform {
-		return true
+	var bidExt openrtb_ext.ExtBid
+	if err := jsonutil.Unmarshal(bid.Bid.Ext, &bidExt); err != nil {
+		return nil
 	}
-	return false
+	return bidExt.DSA
 }