Best way to Inject IDbConnectionFactory in .net core app

1

Hi,
I am using .net core injection (IServiceProvider) and I wonder how can I inject IDbConnectionFactory in order to avoid using (var db = this.dbConnection.Open()) each time.
Also, what is the best life cycle recommened? AddSingleton, AddTransient, AddScoped ?
Sort code sample would be great.

Thanks

2

Inside ServiceStack Services you don’t need to open a connection you can access the Db computed property directly, e.g:

public object Any(MyRequest request) => Db.Single<Table>(x => x.Id = request.Id);

After the request is completed when the Service is disposed it will also dispose the connection.

If you need access in a different dependency you can pass it in as an argument:

public object Any(MyRequest request) => MyRepo.GetTableById(Db, request.Id);

You’ll need use your Service Db connection if you want to utilize and of the Multitenancy features or fetch the connection from HostContext.AppHost.GetDbConnection(Request) manually.

Alternatively you can have a base class with a lazy property which is similar to how ServiceStack Services work, this is the implementation of ServiceStack’s RepositoryBase class:

public abstract class RepositoryBase : IDisposable, IRepository
{
    public virtual IDbConnectionFactory DbFactory { get; set; }

    IDbConnection db;
    public virtual IDbConnection Db => db ?? (db = DbFactory.OpenDbConnection());

    public virtual void Dispose() => db?.Dispose();
}

So your classes that need data access can also access the lazy Db property, e.g:

public MyRepo : RepositoryBase 
{
    public Table GetTableById(int id) => Db.SingleById<Table>(id);
}

As the IDbConnection is not threadsafe it should be registered as transient, only the IDbConnectionFactory should be registered as a singleton.

3

Thanks but at the moment im not using ServiceStack services. I am using .net core injection.

4

The lazy property approach in RepositoryBase still applies only that you’d need to use constructor injection since .net core DI doesn’t support property injection.

Otherwise you can use transient scope I just don’t like the lifecycle of important pooled resources left to a DI, inside a ServiceStack Service it’s disposed of immediately after the Service is executed so it’s returned to the pool immediately instead of whenever the DI disposes it.

5

So this should to be injected as transient to the constructor?

6

I’d only be injecting the singleton IDbConnectionFactory dependency, e.g:

public abstract class RepositoryBase : IDisposable, IRepository
{
    public IDbConnectionFactory DbFactory { get; }
    protected RepositoryBase(IDbConnectionFactory factory) => DbFactory=factory;

    IDbConnection db;
    public virtual IDbConnection Db => db ??= DbFactory.OpenDbConnection();

    public virtual void Dispose() => db?.Dispose();
}

The classes that inherit your base class would need to be transient, e.g:

public class MyRepo : RepositoryBase
{
    public MyRepo(IDbConnectionFactory factory) : base(factory) { }
}

//...

services.AddTransient<MyRepo>();

You could register the IDbConnection resource itself as transient, e.g:

services.AddSingleton<IDbConnectionFactory>(dbFactory);
services.AddTransient(c => c.Resolve<IDbConnectionFactory>().OpenDbConnection());

I’m just not a fan of relying on the DI life cycle for important resources.

7

I Agree with the last comment.
If ill see side effect, ill digg more.
Thank you!