OnTopic Editor

The OnTopic.Editor.AspNetCore project provides a web-based interface for the OnTopic Library. The editor is distributed as a Razor Class Library via NuGet so it can easily be added to a website that implements the OnTopic.AspNetCore.Mvc library.

Contents

• Installation
• Configuration
  • Services
  • Routes
  • Dependencies
    • IControllerActivator
    • IViewComponentActivator

Installation

Installation can be performed by providing a <PackageReference /> to the OnTopic.Editor.AspNetCore.All NuGet metapackage.

<Project Sdk="Microsoft.NET.Sdk.Web">
  …
  <ItemGroup>
    <PackageReference Include="OnTopic.Editor.AspNetCore.All" Version="5.0.0" />
  </ItemGroup>
</Project>

Configuration

There are a lot of moving parts to the editor, and it requires the configuration of services, routes, and service dependencies. This process is aided by a set of extension methods, which are recommended.

Services

The editor necessitates a custom model binder—AttributeBindingModelBinderProvider—in order to work properly. This can be manually configured via AddMvcOptions(), or can be added using the AddTopicEditor() extension method:

public class Startup {
  …
  public void ConfigureServices(IServiceCollection services) {
    services.AddControllersWithViews()
      .AddTopicSupport()
      .AddTopicEditor();
  }
}

Routes

The editor lives in an area called Editor and a controller called EditorController. A custom route can be conigured using the MapTopicEditorRoute() extension method to setup the /OnTopic route (e.g., /OnTopic/Edit/Root/Web):

public class Startup {
  …
  public void Configure(IApplicationBuilder app, IWebHostEnvironment env) {
    app.UseEndpoints(endpoints => {
      endpoints.MapTopicEditorRoute();
    });
  }
}

Dependencies

The editor is implemented through a set of ASP.NET Core View Components, some of which have external dependencies on a ITopicRepository. These should be configured via dependency injection. If you're using a dependency injection container, those dependencies should be the same as those required for the OnTopic Library. If you are manually configuring your dependencies, however, then the following provides a bare-bones example:

IControllerActivator

public class ControllerActivator : IControllerActivator {
  …
  public object Create(ControllerContext context) {
    var type = context.ActionDescriptor.ControllerTypeInfo.AsType();
    if (type == typeof(EditorController)) {
      return new EditorController(_topicRepository, _topicMappingService);
    }
  }
}

Note: This assumes a _topicRepository and _topicMappingService have already been configured; see the OnTopic.AspNetCore.Mvc documentation for details.

IViewComponentActivator

The StandardEditorComposer class acts as a clearing house for accepting common dependencies and then composing the appropriate dependency graph for the view components:

public class ViewComponentActivator : IViewComponentActivator {
  …
  public object Create(ViewComponentContext context) {

    var standardEditorComposer = new StandardEditorComposer(_topicRepository, _webHostEnvironment);
    var type                   = context.ViewComponentDescriptor.TypeInfo.AsType();

    if (standardEditorComposer.IsEditorComponent(type)) {
      return standardEditorComposer.ActivateEditorComponent(type, _topicRepository);
    }
  }
} 

Note: For a full example, see the SampleActivator in the OnTopic.Editor.AspNetCore.Host project.