Alkimi: Add imp extension support

adapters/alkimi/alkimi.go

@@ -24,10 +24,6 @@ type adapter struct {
 	endpoint string
 }
 
-type extObj struct {
-	AlkimiBidderExt openrtb_ext.ExtImpAlkimi `json:"bidder"`
-}
-
 // Builder builds a new instance of the Alkimi adapter for the given bidder with the given config.
 func Builder(bidderName openrtb_ext.BidderName, config config.Adapter, server config.Server) (adapters.Bidder, error) {
 	endpointURL, err := url.Parse(config.Endpoint)
@@ -67,15 +63,15 @@ func updateImps(bidRequest openrtb2.BidRequest) ([]openrtb2.Imp, []error) {
 	updatedImps := make([]openrtb2.Imp, 0, len(bidRequest.Imp))
 	for _, imp := range bidRequest.Imp {
 
-		var bidderExt adapters.ExtImpBidder
+		var bidderExt = make(map[string]json.RawMessage)
 		var extImpAlkimi openrtb_ext.ExtImpAlkimi
 
 		if err := jsonutil.Unmarshal(imp.Ext, &bidderExt); err != nil {
 			errs = append(errs, err)
 			continue
 		}
 
-		if err := jsonutil.Unmarshal(bidderExt.Bidder, &extImpAlkimi); err != nil {
+		if err := jsonutil.Unmarshal(bidderExt["bidder"], &extImpAlkimi); err != nil {
 			errs = append(errs, err)
 			continue
 		}
@@ -92,15 +88,24 @@ func updateImps(bidRequest openrtb2.BidRequest) ([]openrtb2.Imp, []error) {
 		imp.Instl = extImpAlkimi.Instl
 		imp.Exp = extImpAlkimi.Exp
 
-		temp := extObj{AlkimiBidderExt: extImpAlkimi}
-		temp.AlkimiBidderExt.AdUnitCode = imp.ID
+		temp := extImpAlkimi
+		temp.AdUnitCode = imp.ID
+
+		tempJson, err := jsonutil.Marshal(temp)
+		if err != nil {
+			errs = append(errs, err)
+			continue
+		}
+
+		newExt := bidderExt
+		newExt["bidder"] = tempJson
 
-		extJson, err := json.Marshal(temp)
+		newExtJson, err := jsonutil.Marshal(newExt)
 		if err != nil {
 			errs = append(errs, err)
 			continue
 		}
-		imp.Ext = extJson
+		imp.Ext = newExtJson
 		updatedImps = append(updatedImps, imp)
 	}