Customize the Repository

In most of the circumstances, the default functions provided by the repository are enough, implementing the CRUD operations, but sometimes you need to add some custom functions to the repository.

For example, you may want to add a function to get all the users that have a specific role, or you may want to add a function to get all the users that have a specific role and are active: in this case, you can use the query functions provided by implementations of the IQueryableRepository or the IFilterableRepository interface, when a driver supports them.

Your Custom Repository

Depending on your desining style, you might want to extend the IRepository<TEntity> interface contract, or you might want to extend the specific drivers implementations, for example the MongoRepository<TEntity>.

If your intention is to being agnostic from the driver, you should extend the IRepository<TEntity> interface, for example:

public interface IUserRepository : IRepository<User> {
    Task<IEnumerable<User>> GetUsersByRoleAsync(string role);
}

or even more generic:

public interface IUserRepository<TUser> : IRepository<TUser> where TUser : class, IUser {
    Task<IEnumerable<User>> GetUsersByRoleAsync(string role);
}

Registering the Custom Repository

Once you have defined your custom repository, you need to register it in the Startup class, in the ConfigureServices method:

public void ConfigureServices(IServiceCollection services) {
    // ...
    services.AddRepository<UserRepository>();
    // ...
}

The provided AddRepository extension method will register the repository as a scoped service by default, but you can still specify the lifetime you prefer.

The method is smart enough to scan the type specified for its base classes and interfaces that implement the IRepository<TEntity> interface, and register them as well.

In fact, once you have invoked the above method, you will have the following services registered:

Service Type	Description
UserRepository	The concrete implementation of the custom repository you have defined
IUserRepository	The custom repository contract you have defined
IRepository<User>	The default repository for the User entity

If your custom IRepository<TEntity> implements the IQueryableRepository<TEntity> or the IFilterableRepository<TEntity> interface, the AddRepository method will register the following services as well:

Service Type	Description
IQueryableRepository<User>	A queryable repository for the User entity
IFilterableRepository<User>	A filterable repository for the User entity