How to add global route prefix in asp.net core 3?

Question

Legacy .net core frameworks used UseMvc() for adding global route prefix. How to make it for asp.net core 3 without UseMvc() ?

Answer 1

You could refer to below demo in asp.net core 3.0 to set global route prefix with api version.You could set any prefix as you like by changing services.AddControllersWithViews(o => { o.UseGeneralRoutePrefix("api/v{version:apiVersion}"); });

1.Create a custom MvcOptionsExtensions

public static class MvcOptionsExtensions
{
    public static void UseGeneralRoutePrefix(this MvcOptions opts, IRouteTemplateProvider routeAttribute)
    {
        opts.Conventions.Add(new RoutePrefixConvention(routeAttribute));
    }

    public static void UseGeneralRoutePrefix(this MvcOptions opts, string 
    prefix)
    {
        opts.UseGeneralRoutePrefix(new RouteAttribute(prefix));
    }
}

public class RoutePrefixConvention : IApplicationModelConvention
{
    private readonly AttributeRouteModel _routePrefix;

    public RoutePrefixConvention(IRouteTemplateProvider route)
    {
        _routePrefix = new AttributeRouteModel(route);
    }

    public void Apply(ApplicationModel application)
    {
        foreach (var selector in application.Controllers.SelectMany(c => c.Selectors))
        {
            if (selector.AttributeRouteModel != null)
            {
                selector.AttributeRouteModel = AttributeRouteModel.CombineAttributeRouteModel(_routePrefix, selector.AttributeRouteModel);
            }
            else
            {
                selector.AttributeRouteModel = _routePrefix;
            }
        }
    }
}

2.Register in Startup.cs( you need to install package Microsoft.AspNetCore.Mvc.Versioning ,current version for 3.0 is 4.0.0-preview8.19405.7)

public void ConfigureServices(IServiceCollection services) {
    //MVC service registration
    //https://learn.microsoft.com/en-us/aspnet/core/migration/22-to-30?view=aspnetcore-3.0&tabs=visual-studio#mvc-service-registration
    services.AddControllersWithViews(o = >{
        o.UseGeneralRoutePrefix("api/v{version:apiVersion}");
    });

    services.AddApiVersioning(o = >o.ReportApiVersions = true);
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env) {

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

    app.UseRouting();

    app.UseAuthentication();
    app.UseAuthorization();

    app.UseEndpoints(endpoints = >{
        endpoints.MapControllerRoute(
        name: "default", pattern: "{controller=Home}/{action=Index}/{id?}");
        endpoints.MapRazorPages();
    });
}

3.Controller:

[ApiVersion("1")]
[ApiVersion("2")]
[Route("test")]
[ApiController]
public class TestController : ControllerBase
{
    [HttpGet("version"), MapToApiVersion("1")]
    public IActionResult GetV1()
    {
        return new OkObjectResult("Version One");
    }
}

4.Result

Calling /api/v1/test/version results in "Version One".