Arch / AutoHistory

A plugin for Microsoft.EntityFrameworkCore to support automatically recording data changes history.

AutoHistory

A plugin for Microsoft.EntityFrameworkCore to support automatically recording data changes history.

How to use

AutoHistory will recording all the data changing history in one Table named AutoHistories, this table will recording data UPDATE, DELETE history.

1. Install AutoHistory Package

Run the following command in the Package Manager Console to install Microsoft.EntityFrameworkCore.AutoHistory

PM> Install-Package Microsoft.EntityFrameworkCore.AutoHistory

2. Enable AutoHistory

public class BloggingContext : DbContext
{
    public BloggingContext(DbContextOptions<BloggingContext> options)
        : base(options)
    { }

    public DbSet<Blog> Blogs { get; set; }
    public DbSet<Post> Posts { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // enable auto history functionality.
        modelBuilder.EnableAutoHistory();
    }
}

3. Ensure AutoHistory in DbContext. This must be called before bloggingContext.SaveChanges() or bloggingContext.SaveChangesAsync().

bloggingContext.EnsureAutoHistory()

If you want to record data changes for all entities (except for Added - entities), just override SaveChanges and SaveChangesAsync methods and call EnsureAutoHistory() inside overridden version:

public class BloggingContext : DbContext
{
    public BloggingContext(DbContextOptions<BloggingContext> options)
        : base(options)
    { }
    
    public override int SaveChanges()
    {
        this.EnsureAutoHistory();
        return base.SaveChanges();
    }
    
    public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = new CancellationToken())
    {
        this.EnsureAutoHistory();
        return base.SaveChangesAsync(cancellationToken);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // enable auto history functionality.
        modelBuilder.EnableAutoHistory();
    }
}

4. If you also want to record Added - Entities, which is not possible per default, override SaveChanges and SaveChangesAsync methods this way:

public class BloggingContext : DbContext
{
    public override int SaveChanges()
    {
        var addedEntities = this.ChangeTracker
                                .Entries()
                                .Where(e => e.State == EntityState.Added)
                                .ToArray(); // remember added entries,
        // before EF Core is assigning valid Ids (it does on save changes, 
        // when ids equal zero) and setting their state to 
        // Unchanged (it does on every save changes)
        this.EnsureAutoHistory();
        base.SaveChanges();

        // after "SaveChanges" added enties now have gotten valid ids (if it was necessary)
        // and the history for them can be ensured and be saved with another "SaveChanges"
        this.EnsureAddedHistory(addedEntities);
        base.SaveChanges();
    }   
}

Use Custom AutoHistory Entity

You can use a custom auto history entity by extending the Microsoft.EntityFrameworkCore.AutoHistory class.

class CustomAutoHistory : AutoHistory
{
    public String CustomField { get; set; }
}

Then register it in the db context like follows:

modelBuilder.EnableAutoHistory<CustomAutoHistory>(o => { });

Then provide a custom history entity creating factory when calling EnsureAutoHistory. The example shows using the factory directly, but you should use a service here that fills out your history extended properties(The properties inherited from AutoHistory will be set by the framework automatically).

db.EnsureAutoHistory(() => new CustomAutoHistory()
                    {
                        CustomField = "CustomValue"
                    });

Excluding properties from AutoHistory

You can now excluded properties from being saved into the AutoHistory tables by adding a custom attribute[ExcludeFromHistoryAttribute] attribute to your model properties.

    public class Blog
    {        
        [ExcludeFromHistory]
        public string PrivateURL { get; set; }
    }

Integrate AutoHistory into other Package

Microsoft.EntityFrameworkCore.UnitOfWork had integrated this package.