Delete Trigger to Ensure Unique Constraints

EnsureHelper.cs

public static class EnsureHelper
	{
		private const string EnsureUniqueConstraint = "Ensure-Unique-Constraint";

		public static IList<PropertyInfo> GetPropertiesFromMetadata(JObject metadata)
		{
			var clrType = metadata.Value<string>("Raven-Clr-Type");

			if (clrType != null)
			{
				var type = Type.GetType(clrType);

				return type != null
				       	? type.GetProperties().Where(p => Attribute.IsDefined(p, typeof(EnsureUniqueAttribute), true)).ToList()
				       	: null;
			}

			return null;
		}
	}

EnsureUniqueDeleteTrigger.cs

public class EnsureUniqueDeleteTrigger : AbstractDeleteTrigger
	{
		private const string EnsureUniqueConstraint = "Ensure-Unique-Constraint";

		public override void OnDelete(string key, Raven.Http.TransactionInformation transactionInformation)
		{
			if (key.StartsWith("Raven"))
				return;
			
			var doc = Database.Get(key, transactionInformation);

			if (doc == null) 
				return;

			var metadata = doc.Metadata;

			if (metadata.Value<bool>(EnsureUniqueConstraint))
				return;

			var pseudoKey = key.Substring(0, key.IndexOf("/"));
			var deleteCommands = new List<DeleteCommandData>();

			foreach (var propertyInfo in EnsureHelper.GetPropertiesFromMetadata(metadata)) 
			{
				var checkKey = pseudoKey + "/" + propertyInfo.Name.ToLowerInvariant() + "/" +
				               doc.ToJson().Value<string>(propertyInfo.Name);
				deleteCommands.Add(new DeleteCommandData()
					{
						Etag = null, Key = checkKey, TransactionInformation = transactionInformation
					});
			}

			Database.Batch(deleteCommands);
		}
	}

EnsureUniquePutTrigger.cs

public class EnsureUniquePutTrigger : AbstractPutTrigger
	{
		private const string EnsureUniqueConstraint = "Ensure-Unique-Constraint";

		public override VetoResult AllowPut(string key, JObject document, JObject metadata, Raven.Http.TransactionInformation transactionInformation)
		{
			if (key.StartsWith("Raven")) 
			{
				return VetoResult.Allowed;
			}

			if (metadata.Value<bool>(EnsureUniqueConstraint)) 
			{
				return VetoResult.Allowed;
			}

			var pseudoKey = key.Substring(0, key.IndexOf("/"));

			foreach (var propertyInfo in EnsureHelper.GetPropertiesFromMetadata(metadata)) 
			{
				var checkKey = pseudoKey + "/" + propertyInfo.Name.ToLowerInvariant() + "/" + document.Value<string>(propertyInfo.Name);
				var checkDoc = Database.Get(checkKey, transactionInformation);
				if (checkDoc != null)
				{
					var checkId = checkDoc.ToJson().Value<string>("Id");

					if (checkId != key)
					{
						return VetoResult.Deny("Ensure unique constraint violated for field: " + propertyInfo.Name);
					}
				}
			}

			return VetoResult.Allowed;
		}

		public override void OnPut(string key, JObject document, JObject metadata, Raven.Http.TransactionInformation transactionInformation)
		{
			if (key.StartsWith("Raven"))
			{
				return;
			}

			if (metadata.Value<bool>(EnsureUniqueConstraint))
			{
				return;
			}

			var putCommands = new List<PutCommandData>();
			var pseudoKey = key.Substring(0, key.IndexOf("/"));

			foreach (var propertyInfo in EnsureHelper.GetPropertiesFromMetadata(metadata)) 
			{
				var checkId = propertyInfo.Name.ToLowerInvariant();
				putCommands.Add(new PutCommandData() 
				{
					Key = pseudoKey + "/" + checkId + "/" + document.Value<string>(propertyInfo.Name),
					Etag = null,
					Metadata = new JObject(new JProperty(EnsureUniqueConstraint, true)),
					Document = new JObject(new JProperty("Id", key))
				});
			}

			if (putCommands.Count > 0)
			{
				Database.Batch(putCommands);
			}
		}
	}