get connection obj and insert if not present

Author: Hitenjain14

code/go/0chain.net/blobbercore/allocation/allocationchange.go

@@ -162,6 +162,34 @@ func GetAllocationChanges(ctx context.Context, connectionID, allocationID, clien
 	return nil, err
 }
 
+func GetConnectionObj(ctx context.Context, connectionID, allocationID, clientID string) (*AllocationChangeCollector, error) {
+	cc := &AllocationChangeCollector{}
+	db := datastore.GetStore().GetTransaction(ctx)
+	err := db.Where("id = ? and allocation_id = ? and client_id = ?",
+		connectionID,
+		allocationID,
+		clientID,
+	).Take(cc).Error
+
+	if err == nil {
+		return cc, nil
+	}
+
+	if err == gorm.ErrRecordNotFound {
+		cc.ID = connectionID
+		cc.AllocationID = allocationID
+		cc.ClientID = clientID
+		cc.Status = NewConnection
+		err = cc.Save(ctx)
+		if err != nil {
+			return nil, err
+		}
+		return cc, nil
+	}
+
+	return nil, err
+}
+
 func (cc *AllocationChangeCollector) AddChange(allocationChange *AllocationChange, changeProcessor AllocationChangeProcessor) {
 	cc.AllocationChanges = append(cc.AllocationChanges, changeProcessor)
 	allocationChange.Input, _ = changeProcessor.Marshal()

code/go/0chain.net/blobbercore/handler/object_operation_handler.go

@@ -1297,7 +1297,7 @@ func (fsh *StorageHandler) WriteFile(ctx context.Context, r *http.Request) (*all
 	}
 	// Update/Save the change
 	if res.UpdateChange {
-		dbConnectionObj, err := allocation.GetAllocationChanges(ctx, connectionID, allocationID, clientID)
+		dbConnectionObj, err := allocation.GetConnectionObj(ctx, connectionID, allocationID, clientID)
 		if err != nil {
 			return nil, err
 		}