Auto-Resource, Repository, and Service Discovery

[jaredcnance]

We should be able to reflect on the assembly and auto discover all implementations of IIdentifiable<,>, IResourceService<,>, IEntityRepository<,> adding them to the ContextGraph. A possible API might look like:

public void ConfigureServices(IServiceCollection services)
{
    services.AddJsonApi(options => 
        options.BuildContextGraph((builder) => 
            builder.AddAssembly(/*...*/);
        );
    );
}

We may also expose the following for finer control:

builder.AddAssemblyResources(/* ... */); // should also register ResourceDefinitions
builder.AddAssemblyServices(/* ... */);
builder.AddAssemblyRepositories(/* ... */);

This work may include improved handling for multiple database contexts. See #269. In order to automatically handle multiple contexts, we need a way to specify that FooRepository depends on BarDbContextResolver at startup. Currently, I don't think Microsoft's DI library provides anything with that level of registration. We could consider providing a separate package that depends on Autofac (for example) where we explicitly construct the dependency graph.

[jaredcnance]

v3.0.0-beta Notes

We need help from you: if you’re interested in helping get this feature fully released, download the 3.0.0-beta version(s) and provide feedback in this issue or you can open a new issue for bug reports. Thanks!!

Public Resource Name Resolution

• Check class definition for attribute [Resource("models"]

[Resource("models"] public class Model : Identifiable { /* ... */ }

• Check DbSet for attribute (will probably deprecate this in the future)

[Resource("models")] public DbSet<Model> Models { get; set; }

• Check for IResourceNameFormatter

• Fallback to dasherized

TODO

• Improve DX around IResourceNameFormatter. Currently manually passed into ServiceDiscoveryFacade and ContextGraphBuilder...It should only be specified once. Maybe we should just locate it in the ServiceDiscoveryFacade ?

Known Bug List

• Fixed in v3.0.0-beta2

Unhandled Exception: System.InvalidOperationException: JsonApiDotNetCore.Data.IEntityRepository`2[TodoListAPI.Models.TodoItem,System.Int32] is not a GenericTypeDefinition. MakeGenericType may only be called on a type for which Type.IsGenericTypeDefinition is true.
   at System.RuntimeType.MakeGenericType(Type[] instantiation)
   at JsonApiDotNetCore.Graph.TypeLocator.GetGenericInterfaceImplementation(Assembly assembly, Type openGenericInterfaceType, Type[] genericInterfaceArguments) in C:\projects\jsonapidotnetcore\src\JsonApiDotNetCore\Graph\TypeLocator.cs:line 88
   at JsonApiDotNetCore.Graph.ServiceDiscoveryFacade.RegisterServiceImplementations(Assembly assembly, TypeinterfaceType) in C:\projects\jsonapidotnetcore\src\JsonApiDotNetCore\Graph\ServiceDiscoveryFacade.cs:line 133
   at JsonApiDotNetCore.Graph.ServiceDiscoveryFacade.AddAssemblyServices(Assembly assembly, IResourceNameFormatter resourceNameFormatter) in C:\projects\jsonapidotnetcore\src\JsonApiDotNetCore\Graph\ServiceDiscoveryFacade.cs:line 44
   at TodoListAPI.Startup.<>c.<ConfigureServices>b__4_1(ServiceDiscoveryFacade discovery) in /Users/jarnance/dev/TodoListExample/TodoListAPI/Startup.cs:line 45
   at JsonApiDotNetCore.Extensions.IServiceCollectionExtensions.AddJsonApi(IServiceCollection services, Action`1 configureOptions, IMvcCoreBuilder mvcBuilder, Action`1 autoDiscover) in C:\projects\jsonapidotnetcore\src\JsonApiDotNetCore\Extensions\IServiceCollectionExtensions.cs:line 71
   at TodoListAPI.Startup.ConfigureServices(IServiceCollection services) in /Users/jarnance/dev/TodoListExample/TodoListAPI/Startup.cs:line 42