ASP.NET Core example API

Tutorial to create this project

Write tutorial code without copying directly to reinforce learning

Initial Project Files

Download the .NET Core SDK in dotnet.microsoft

Choose your O.S, windows, linux or macOS. Click the "Download .NET Core SDK" button, this tutorial follows version 2.2

Once installed, run the command on your terminal:

dotnet --version

If all is right, your .NET version will appear.

You can run the command:

dotnet new --help

To know what types of project templates can be created, how are we going to create an API, the option would be "ASP.NET Core Web API"

Run the command to create the Web API project named "MyApp"

dotnet new webapi -o MyApp

This commmit has all the files that will be generated

Run cd MyApp to enter in the MyApp folder

Entities and Database

Run the command to add the ORM in this case EF Core with SQLite database

dotnet add package Microsoft.EntityFrameworkCore.Sqlite

Add folder Models and Movies inside it, create the entity named Movie.cs, that will be represented as table Movies in database

Create file ApplicationDbContext.cs this file contains all entities that will be mapped in the database

In Startup.cs file add, the following code after AddMvc and SetCompatibilityVersion methods

services.AddDbContext<ApplicationDbContext>(options => options.UseSqlite("Data Source=myapp.db"));

The AddDbContext method is responsible for telling which db context will be used by the project, in this case ApplicationDbContext class

Managers

Managers encapsulates business logic that doesn't naturally fit within a domain object

Add IMovieManager.cs and MovieManager.cs files who are responsible for manipulating the movie entity

Add the following code before AddDbContext method in Startup class

services.AddScoped<IMovieManager, MovieManager>();

This line of code defines which implementation the IMovieManager interface will use

Controllers

Controllers handles incoming HTTP requests and send response back to the caller.

Remove ValuesController that has generated in the dotnet new command that in be not used in this tutorial

Create MoviesController.cs class that have the following methods:

Verb	URL	Description
GET	api/movies	return all movies
GET	api/movies/5	get a movie based on its id
POST	api/movies	creates a movie
PUT	api/movies/5	update an existing movie
DELETE	api/movies/5	delete a movie based on its id

Controllers uses Managers to do business logic operations

Add Directors

A director can have multiple movies, and a movie can have only one director

Create Director.cs, IDirectorManager.cs and DirectorManager.cs files

Add public DbSet<Director> Directors { get; set; } in ApplicationDbContext.cs file

And add services.AddScoped<IDirectorManager, DirectorManager>(); in Startup.cs file

Create DirectorsController.cs inside Controllers folder

In Models/Movies/Movie.cs file add

public long DirectorId { get; set; }
public Director Director { get; set; }

In Models/Movies/MovieManager.cs file change GetAll() and GetById() methods

public async Task<List<Movie>> GetAll()
{
    return await _context.Movies.Include(m => m.Director).ToListAsync();
}

public async Task<Movie> GetById(long id)
{
    return await _context.Movies.Include(m => m.Director)
                                .AsNoTracking()
                                .FirstOrDefaultAsync(m => m.Id == id);
}

To include the director in the movie

Create Database

Run the command, to created the database migrations and snapshot, which is the C# code that represents the database dotnet ef migrations add InitialCreate

Apply the changes dotnet ef database update

Run

dotnet build

dotnet run