Hello All,

Recently, I published a video course on ASP.NET Web API using ASP.NET Core framework. Initially, when I started working on it, it was named as ASP.NET 5 and as it progressed till last section, Microsoft announced to rename it as ASP.NET Core and RC2 got released few days prior to the course release date. Microsoft took more than six months to release the next RC version. Although the concept was same but there were major changes in tooling and libraries. As it was not the final version so we decided to provide the details of differences once RTM releases.

In this post, I will be putting the details of the changes by section and also update the sample which will be available with the course. As ASP.NET 5 got renamed to ASP.NET Core, accordingly the names of libraries got changed to ASP.NET Core as well so we need to change all the references. The following table contains the details of packages that we need to update in our sample with the video number.

Updated sample is available with the course and refer the project.json to find the updated references. Also, Microsoft again reintroduced web.config file but it will be there along with Project.json.

Note – The details will be included for only for those those sections where changes are required.

Section 2   
As this was the first section where we started our discussion on ASP.NET Core Web API and started working on our sample so this section got many changes. Let’s discuss each

Video 2.1 : There are changes in the project creation flow. Earlier when we used to create ASP.NET Core project, it used to have two sets of references – one for core and other for full framework. We either used to build the application using both the framework and remove one based on our needs. As there were many libraries which could not work in both the platforms so Microsoft has provided the option to select the framework upfront while creating the project which makes the complete process simpler. Also, in real world scenarios, there are rare chances when we need to build the binaries for both the framework.  Now when we open New Project window and select web from left side then we get three options as
Here we have three options.

1. First one is a traditional ASP.NET application using .NET 4.6.
2. Selected one is ASP.NET Core application using .NET Core framework and the same is used in our course.
3. Third one is again ASP.NET Core application but uses the standard .NET framework.

When we select the second option, it shows the following dialog

It also got revamped completely. We had earlier lots of options which included standard ASP.NET templates. Now it contains only ASP.NET Core templates and has three options same as earlier ASP.NET 5 templates and we used the empty template for our course. Just to mention again, now we have just one bag named as .NETCoreApp,Version=v1.0  which contains set of libraries for .NET Core only in the references.

There are some more changes as below

a) Earlier we used to have following line in startup.cs which was entry point for the web application

// Entry point for the application.
public static void Main(string[] args) => WebApplication.Run<Startup>(args);

but now we have a new file program.cs which contains the main method which is now entry point for the web application.

b) Configuration file web.config is also back in project file and available along with project.json although all the settings should be put in project.json and we will be using the same.

c) There are also changes in the number of the parameters in ConfigureServices method in startup.cs which includes Hosting Environment and logger factory but we will not be using it in our sample.

Video 2.2: Only change in the references. Refer the initial table.

Video 2.3: In this video, we discussed that there are four options to register a service but we found AddSingleton and AddInstance very similar, both allows single instance across multiple requests with a difference in the instance creation. Now we have only AddSingleton where either we can pass the instance or provide the type info as.

To register via interface and class name

services.AddSingleton<IBookStoreRepository, BookStoreRepository>();

and to register an instance

IBookStoreRepository bookStoreRepository = new BookStoreRepository(new BookStoreContext());
services.AddSingleton(bookStoreRepository);

Video 2.4: Only change in the references. Refer the table.

Section 3
In this section we added CRUD operations to our sample using  HTTP verbs. Only few changes are required in the section as mentioned below.

Video 3.2: Microsoft did an awesome change with it by making the JSON response in camel case by default. In our sample we added serialize settings in statrtup.cs as

options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();

It is no more required.

Video 3.3 :  We returned various status codes from the action methods based on the request.The classes that we used also got renamed as

The above changes has taken place in all the action methods wherever used.

Section 4 
In this section, we added few more features to our sample like sorting, paging etc. Here there is a change in the way we access URL Helper as discussed below.

Video 4.3: We used URL helper for generating the URLs and it was injected via constructor without any other changes as it was by default available which is not the case now.

Now we need to access it via UrlHelperFactory and action context. ActionContext is accessed via ActionContextAccessor, for that we need to register it in startup.cs as

services.AddSingleton<IActionContextAccessor, ActionContextAccessor>();

and we need to inject the UrlHelperFactory and ActionContextAccessor in constructor to get the URL helper as

  public BooksController(IBookStoreRepository _repository, IUrlHelperFactory urlHelperFactory, IActionContextAccessor actionContextAccessor)
        {
            this.repository = _repository;
            this.urlHelper = urlHelperFactory.GetUrlHelper(actionContextAccessor.ActionContext);
        }

Rest of the code would be same as we got the similar URL helper.

Section 5
In this section we talked about security implementation. In it we have only few changes as below.

Video 5.2 : We created a custom authorization attribute RequireHttpsAttribute which inherited from AuthorizationFilterAttribute where we checked the scheme from the URL. Now RequireHttpsAttribute is itself available under the namespace Microsoft.AspNetCore.Mvc so we can use the same to enforce the SSL in complete application or any specific controller/action.

Video 5.4 : Only few references changes. Refer the table

Section 6 
In this section, we discussed some advanced topics like DI, CORS etc and there are few changes in DI. Let’s see that

Video 6.1:
a) As discussed earlier that now we don’t have AddInstance option for registering the service, same can be achieved via AddSingleton.

b) We discussed that we can also inject services via property using FromServices attribute but it is not available any more as it was creating confusion and issues. Constructor injection is always preferable. From services is available and can be used for Action Injection as

public IEnumerable<Book> Get([FromServices] IBookStoreRepository repository)
{
...
}

These are the key changes that took place specific to Web API and our course. I created again the sample from scratch using the ASP.NET Core 1.0 which can be downloaded from the course.

Thanks a lot for your support and feedback.

Cheers
Brij