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Hooks
Paul Stovell edited this page Apr 17, 2020
·
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Hooks provide a way for you to be notified when Nevermore is about to insert, update, or delete a document, or commit a transaction.
Hooks are useful when you need to handle some cross-cutting concerns:
- To build an audit trail
- To keep something else in sync when a document changes
You create a hook by implementing IHook
. There are default implementations for each, so you only need to implement the method you want (see default interface methods).
For example, maybe certain documents should be "read-only" and cannot be edited.
class ReadOnlyHook : IHook
{
public void BeforeUpdate(object document, DocumentMap map, IWriteTransaction transaction)
{
if (document is IReadOnly)
throw new Exception("This document is read-only!");
}
}
You then register your hook with the store:
Configuration.HookRegistry.Register(new ReadOnlyHook());
Here are the methods you can implement:
public interface IHook
{
void BeforeInsert(object document, DocumentMap map, IWriteTransaction transaction);
void AfterInsert(object document, DocumentMap map, IWriteTransaction transaction);
void BeforeUpdate(object document, DocumentMap map, IWriteTransaction transaction);
void AfterUpdate(object document, DocumentMap map, IWriteTransaction transaction);
void BeforeDelete(string id, DocumentMap map, IWriteTransaction transaction);
void AfterDelete(string id, DocumentMap map, IWriteTransaction transaction);
void BeforeCommit(IWriteTransaction transaction);
void AfterCommit(IWriteTransaction transaction);
Task BeforeInsertAsync(object document, DocumentMap map, IWriteTransaction transaction);
Task AfterInsertAsync(object document, DocumentMap map, IWriteTransaction transaction);
Task BeforeUpdateAsync(object document, DocumentMap map, IWriteTransaction transaction);
Task AfterUpdateAsync(object document, DocumentMap map, IWriteTransaction transaction);
Task BeforeDeleteAsync(string id, DocumentMap map, IWriteTransaction transaction);
Task AfterDeleteAsync(string id, DocumentMap map, IWriteTransaction transaction);
Task BeforeCommitAsync(IWriteTransaction transaction);
Task AfterCommitAsync(IWriteTransaction transaction);
}
Overview
Getting started
Extensibility
Misc