Swagger, open api with .net Core 3.0

Question

I have a .net core 3.0 application and I am trying to implement Swashbuckle package . So I can do a http get request.

I have a controller like this:

  [Route("api/products")]
    [ApiController]
    public class ProductValuesController : Controller
    {
        private DataContext context;

        public ProductValuesController(DataContext data)
        {
            this.context = data;
        }

        [HttpGet("{id}")]
        public Product GetProduct(long id)
        {
            return context.Products.Find(id);
        }
        public IActionResult Index()
        {
            return View();
        }
    }

and the startup.cs file looks like this:

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)
        {

            string connectionString = Configuration["ConnectionStrings:DefaultConnection"];
            services.AddDbContext<DataContext>(options =>
            options.UseSqlServer(connectionString));

            services.AddControllersWithViews();
            services.AddRazorPages();

            services.AddSwaggerGen(options => {
                options.SwaggerDoc("v1", new OpenApiInfo { Title = "SportsStore", Version = "v1" });
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IServiceProvider services)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                // 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.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

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

            app.UseSwagger();

            app.UseSwaggerUI(options => {
                options.SwaggerEndpoint("/swagger/v1/swagger.json",
                "SportsStore API");
            });

            // SeedData.SeedDatabase(services.GetRequiredService<DataContext>());
        }
    }

But if I start the application and browse to:

https://localhost:5001/swagger/v1/swagger.json

I will see this error:

NotSupportedException: Ambiguous HTTP method for action - ServerApp.Controllers.ProductValuesController.Index (ServerApp). Actions require an explicit HttpMethod binding for Swagger 2.0

So my quesiton is: what I have to change, so that it will work?

Thnak you.

Answer 1

I had this issue as well, it looks like the IActionResult Index() is causing the issue. You can do as mentioned above and decorate it with [NonAction] attribute and then it should fix it.

Answer 2

Decorate your public non - REST methods in the Controller as [NoAction]