Automatic audit fields

Rather than setting audit values manually for every save/update operation, you can obtain a DB instance initialized with the current user’s audit data. The library will then populate audit fields on entities automatically during write operations.

Enable audit fields

Simply add a property of type ModifiedBy to the entity class where you'd like to enable audit fields. The ModifiedBy type is provided by the library. It can be inherited and other properties can be added to it as you please.

public class Book : Entity
{
    public string Title { get; set; }
    public ModifiedBy ModifiedBy { get; set; }
}

Obtain a DB instance

Retrieve a database instance by providing it a ModifiedBy instance with the current user's details filled in.

var currentUser = new ModifiedBy
{
    UserID = "xxxxxxxxxxxx",
    UserName = "Kip Jennings"
};

var db = DB.Instance("SomeDatabase")
           .WithModifiedBy(currentUser);

// if you already have a DB instance
db = db.WithModifiedBy(currentUser);

Perform entity operations

In order for the auto audit fields to work, you must use the exact DB instance that was enriched with the audit values to perform the operations.

db = db.WithModifiedBy(currentUser);
await db.SaveAsync(book);
await db.Update<Book>()
        .MatchID(book.ID)
        .Modify(b => b.Title, "updated title")
        .ExecuteAsync();

Doing so will result in the following document in mongodb:

{
	"_id" : ObjectId("xxxxxxxxxxxx"),
	"Title" : "updated title", //this will initially be 'test book'
	"ModifiedBy" : {
		"UserID" : "xxxxxxxxxxxx",
		"UserName" : "Kip Jennings"
	}
}

Get audit values

The audit values of a DB instance can be read like so:

var currentUser = db.ModifiedBy;

Transaction support

A transaction can be started with audit field support by creating a transaction on an instance that already has the audit values set.

var db = DB.Instance("SomeDatabase").WithModifiedBy(currentUser);

using (var tn = db.Transaction())
{
    await tn.SaveAsync(book);
    await tn.CommitAsync();
}

Note

Please refer to the transactions page for a detailed explanation of how transactions work.