Creating enbdpoints that return OData in ASP.NET Core Web API

Question

I am trying to create OData endpoints in ASP.NET Core Web API.

I created a new ASP.NET Core Web API using the template and added the Microsoft.AspNetCore.OData package (v7.0.0-beta1) to it assuming it is required.

I can't find any documentation on how to get started with this. If anyone can tell me how I would simply turn the default ValuesController to return OData instead of Json that would be great.

Answer 1

I created a new ASP.NET Core Web API using the template and added the Microsoft.AspNetCore.OData package (v7.0.0-beta1) to it assuming it is required.

I can't find any documentation on how to get started with this. If anyone can tell me how I would simply turn the default ValuesController to return OData instead of Json that would be great.

According to your description, I suggest you could try to follow below steps to create net core odata web api.

1.Install the Microsoft.AspNetCore.OData 7.0.0-beta1

2.Install the Microsoft.EntityFrameworkCore

3.Create a model class and DBContext class.

public class Person
{
    [Key]
    public int Id { get; set; }
    [Required]
    public string Name { get; set; }
    [Required]
    public int Age { get; set; }
}

public class ApplicationDbContext : DbContext
{
    public ApplicationDbContext(DbContextOptions options)
        : base(options)
    {
    }


    public DbSet<Person> Persons { get; set; }

}

4.Create a Controller, in earlier versions of OData you can inherit from ODataController. But in ASP.NET Core, there is no OData controller available. So you need to create a normal controller, with OData attributes.

public class PersonController : Controller
{
    private readonly ApplicationDbContext _appDbContext;
    public PersonController(ApplicationDbContext sampleODataDbContext)
    {
        _appDbContext = sampleODataDbContext;
    }

    [EnableQuery]
    public IActionResult Get()
    {
        return Ok(_appDbContext.Persons.AsQueryable());
    }
}

5.Modify the startup class code to add OData middleware and OData routing.

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
        services.AddOData();
        services.AddMvc();

    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        //Adding Model class to OData
        var builder = GetEdmModel(app.ApplicationServices);
        builder.EntitySet<Person>(nameof(Person));

        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseMvc((routebuilder =>
        {
            routebuilder.MapODataServiceRoute("odata","odata", builder.GetEdmModel());
        }));
    }

    private static ODataConventionModelBuilder GetEdmModel(IServiceProvider serviceProvider)
    {
        var builder = new ODataConventionModelBuilder(serviceProvider);

      return builder;
    }
}

6.Open package manager console to create the table: Add-Migration InitialCreate update-database

7.Run the application

Result: