AzureGems Repository - Abstractions

This library provides a CRUD interface for a Generic Repository. The interface also allows you to write LINQ expressions via the Query() method.

IRepository<T>

The IRepository interface does not provide methods that return an IQueryable as it is generally considered to be an anti-pattern.

Instead, the interface provides a Query() method so that you can write Expressions against a provided IQueryable parameter.

For example:

private readonly IRepository<Widget> _widgets; public IEnumerable<Widget> GetWidgetsBelow(double price) { return _widgets.Query(q => q.Where(w => w.SalePrice < price)); }

In the code above, q is of type IQueryable<Widget> and w is of type Widget.

Returning custom models

Each repository is strongly typed and most of the CRUD methods will only return a single/enumerable of the same strong type.

However when using the LINQ Expression with the Query() method we are able to return custom models (view models) using the LINQ .Select() operator.

For example:

IEnumerable<WidgetViewModel> spinners = await widgetsRepo.Query(q => q .Where(w => w.Type == "Spinner") .OrderBy(w => w.Style) .Select(s => new WidgetViewModel() { DisplayName = s.Name + " Spinner", Price = s.SalePrice }) );

NOTE: Returning Anonymous types aren't supported!

Using BaseEntity

This type is used as a generic constraint for the IRepository<T> interface. This means any model of type T must inherit from BaseEntity

It provides the required Id field and the Discriminator field to be used with all models.

TODO: Can BaseEntity be moved to the AzureGems.Repository.CosmosDb implementation?