Can't get Odata 7.1 working in web api (.net core 2.2) - asp.net-core

Question

I'm having trouble implementing OData in my Web API project.
I'm using .NET Core 2.2 and OData (Microsoft.AspNetCore.OData v7.1.0).
(I also have AutoMapper installed, but I don't think this is relevant)
The problem is that the response is never enriched with the extra properties (like odata.context and odata.count). Also, adding ?count=true doesn't do anything either.
Does anyone have any idea why this is happening?
This is my Startup.cs:
public void ConfigureServices(IServiceCollection services)
{
/* AutoMapper config */
var mappingConfig = new MapperConfiguration(mc =>
{
mc.AddProfile(new MappingProfile());
});
IMapper mapper = mappingConfig.CreateMapper();
services.AddSingleton(mapper);
services.AddMvc(opt => opt.EnableEndpointRouting = false).SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
services.AddOData();
var connection = #"snipped-connection-string";
services.AddDbContext<AllOnBoardContext>
(options => options.UseSqlServer(connection));
/* CORS for local development, not ideal, I know */
services.AddCors(setup =>
{
setup.AddPolicy(AllowCorsPolicyName, builder =>
{
builder.AllowAnyOrigin().AllowAnyHeader().AllowAnyMethod();
});
});
}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseCors(AllowCorsPolicyName);
app.UseMvc(routeBuilder =>
{
routeBuilder.Select().Filter().OrderBy().Expand().Count().MaxTop(10);
routeBuilder.MapODataServiceRoute("api", "api", GetEdmModel());
});
}
private static IEdmModel GetEdmModel()
{
ODataConventionModelBuilder builder = new ODataConventionModelBuilder();
builder.EntitySet<Tenant>("Tenants");
return builder.GetEdmModel();
}
And this is my `Controller´ class:
public class TenantController : ControllerBase
{
private ITenantService tenantService;
public TenantController(ITenantService tenantService, IMapper mapper) : base(mapper, tenantService)
{
this.tenantService = tenantService;
}
[HttpGet]
[EnableQuery()]
public ActionResult<IEnumerable<TDto>> Get()
{
return Service.GetAll().ToList();
}
}

Answer 1

First of all, OData query parameters always start with a $. So in your case, it is ?$count=true.
Next, make sure that every Controller inherits from ODataController:
[ODataRoutePrefix("Tenants")]
public class TenantController : ODataController
{
private ITenantService tenantService;
public TenantController(ITenantService tenantService, IMapper mapper) : base(mapper, tenantService)
{
this.tenantService = tenantService;
}
[HttpGet]
[ODataRoute]
[EnableQuery]
public ActionResult<IEnumerable<TDto>> Get()
{
return Service.GetAll().ToList();
}
}
Annotations will help you to control OData. The prefix string of the ODataRoutePrefixAttribute specifies the OData URL path template that this action handles (in your case http://<host:port>/api/Tenants) and with the ODataRouteAttribute it is possible to specify the OData URL path template that this action handles.