Invalid cast exception when audit logging from multiple tables to a single EF audit table

Question

My application uses Audit.NET with Audit.EntityFramework for audit logging data changes. For the purpose of facilitation the creation of audit log / data changes visualisation, I decided to log changes from a few tables into a single one. Long story short: I defined a state machine for my item and I'm logging whats happening with it from when it first appears in my system till when I dispose it.

In order to demonstrate the issues that I'm struggling with, I create a test REST app and made it available on GitHub repository.

The application tracks the lifetime of articles, where an article can come to the system by:

• an article is directly added and linked to a publication - in short, it is ACCEPTED
• an article proposal is added - in short, it is PROPOSED
• a PROPOSED article can be accepted for addition to a publication - in short, it is ACCEPT_PROPOSAL

For some more details, check the public enum ProcessAction.

How to reproduce

1. Clone the repo
2. Create the DB and the user - creation SQL code is contained in a comment in TestDbContext.cs
3. Run the DB migration
4. Start the application
5. Call all endpoints from TestsController.cs in the order they appear - here are direct links (HTTP GET):
   1. Mew Publication: http://localhost:5000/tests/publication/add?name=New%20Publication
   2. Add Article: http://localhost:5000/tests/article/add?type=ReviewArticle&title=Test%20article%202018&note=My%20test%20note&publicationId=1
   3. Propose an article: http://localhost:5000/tests/proposal/add?type=ReviewArticle&title=Test proposal 1&note=Proposal%20note%201
   4. Accept the article proposal (NOTE: the article ID may differ on your system): http://localhost:5000/tests/accept/1?publicationId=2

Issues

1. The last call is throwing the following exception:

   InvalidCastException: Unable to cast object of type
   'si.dezo.test.DotNetAudit.Models.Article' to type
   'si.dezo.test.DotNetAudit.Models.ArticleProposal'.
   

2. I commented out a few lines of code in TestDbContext.cs and marked it as

   NOTE: the below is not working

Am I doing something wrong or is it a limitation or a bug of the library?

Is there a way around the issue?

Answer 1

The problem is that the library is supporting only one action for each Target type (audit type).

When you call .Map with an action like this:

.Map<Article, Audit_Article>((evt, entry, auditTbl) => { /*some action*/ })

It will store the action related to the type Audit_Article, but your next call:

.Map<ArticleProposal, Audit_Article>((item, auditTbl) => { /*overriding action*/ })

will override your previous action for any type that maps to Audit_Article.

So my initial recommendation is to use the common action via .AuditEntityAction<IAudit>. Is that causing you any issues?

I think it's possible to extend the library to allow mapping multiple types to the same target type with independent actions for each. I will take a look.

UPDATE

This has been implemented on Audit.EntityFramework version 13.2.0, you can now have multiple entities mapping to the same audit type with independent action for each.

• Some documentation
• Sample code