Q: c# webapi core 2.0 routing with odata v4.0?

Question

currently i use the webapi and odata and want to create a small test project. The route mapping is currently not working correctly.

I use following libs: - Microsoft.AspNetCore.All (2.0.3) - Microsoft.AspNetCore.Odata (7.0.0-beta1) - newest webapi with core2.0

Configure Section:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }

    //Adding Model class to OData
    var builder = new ODataConventionModelBuilder(app.ApplicationServices);
    builder.EntitySet<Person>($"{nameof(Person)}s");

    //app.
    //app.UseMvcWithDefaultRoute();
    app.UseMvc(routebuilder =>
    {
        routebuilder.EnableDependencyInjection();
        routebuilder.Filter().Expand().Select().OrderBy().MaxTop(null).Count();
        routebuilder.MapODataServiceRoute("odata", "odata", builder.GetEdmModel());
    });
}

Controller Section:

public class PersonsController : ODataController
{
    private static readonly List<Person> myPersons = new List<Person>
    {
        new Person {Firstname = "Person1", Lastname= "Test", Id = "p1"},
        new Person {Firstname = "Person2", Lastname= "Test", Id = "p2"},
        new Person {Firstname= "Person3", Lastname= "Test", Id = "p3"},
        new Person {Firstname= "Person4", Lastname= "Test", Id = "p4"},
    };

    public IQueryable<Person> GetPersons()
    {
        return myPersons.AsQueryable();
    }

    public Person GetPerson([FromODataUri] string key)
    {
        return myPersons.FirstOrDefault(x => x.Id == key);
    }
}

Model Section:

public class Person
{
    [Key]
    public string Id { get; set; }
    public string Firstname{ get; set; }
    public string Lastname { get; set; }
}

In the odata documentation these calls should work now:

• ~/odata/Persons
• ~/odata/Persons('p1')

But they aren't. I always get a page not found result from IIS. What i think is that the MapODataServiceRoute call does not set up the routes correctly. Î dont use any default routes in webapi. Any ideas ?

Answer 1

I tried several things out and found a solution to the problem. The order in the config method is important:

This is working:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    services.AddOData();
}

this NOT:

public void ConfigureServices(IServiceCollection services)
{
    services.AddOData();
    services.AddMvc();
}