Swagger Page is 404 Not Found in MVC net-core

Question

I have a brand new .NET-Core Web API project that I want to use API versioning and swagger.

When I try to view the swagger page I get a 404. However, the default ValuesController that comes with the template works.

Here is my setup:

Startup.cs

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

        // Add API Versioning
        services.AddApiVersioning(
            options =>
            {
                options.DefaultApiVersion = new ApiVersion(1, 0);
                options.AssumeDefaultVersionWhenUnspecified = true;
                options.ReportApiVersions = true;
            });

        // Add Swagger
        string pathToDoc = "RegistriesApi.xml";
        services.AddSwaggerGen(options =>
        {
            options.SwaggerDoc("v1",
                new Info
                {
                    Title = "Registries API",
                    Version = "v1",
                    Description = "A simple api to interact with AMA registries information",
                    TermsOfService = "None"
                });

            string filePath = Path.Combine(PlatformServices.Default.Application.ApplicationBasePath, pathToDoc);
            options.IncludeXmlComments(filePath);
            options.DescribeAllEnumsAsStrings();
        });
    }
    ...
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        // Url Path Rewriter
        RewriteOptions rewriteOptions = new RewriteOptions();
        if (!env.IsDevelopment())
        {
            rewriteOptions.AddRedirectToHttps();
        }
        else
        {
            app.UseDeveloperExceptionPage();
        }
        app.UseRewriter(rewriteOptions);

        // Use MVC
        app.UseMvc(routes =>
        {
            routes.MapRoute(
                name: "default",
                template: "{controller=Home}/{action=Index}/{id?}");
        });

        // Swagger
        app.UseSwagger(c =>
        {
            c.PreSerializeFilters.Add((swagger, httpReq) => swagger.Host = httpReq.Host.Value);
        });
        app.UseSwaggerUI(
            c => { c.SwaggerEndpoint("/swagger/v1/swagger.json", "V1 Docs"); });
    }

ValuesController.cs

[ApiVersion("1.0")]
[Route("api/v{version:apiVersion}/values")]
public class ValuesController : Controller
{
    // GET api/values
    [HttpGet]
    public IEnumerable<string> Get()
    {
        return new[] {"value1", "value2"};
    }

    // GET api/values/5
    [HttpGet("{id}")]
    public string Get(int id)
    {
        return "value";
    }

    // POST api/values
    [HttpPost]
    public void Post([FromBody] string value)
    {
    }

    // PUT api/values/5
    [HttpPut("{id}")]
    public void Put(int id, [FromBody] string value)
    {
    }

    // DELETE api/values/5
    [HttpDelete("{id}")]
    public void Delete(int id)
    {
    }
}

Also, here is the version for all the libraries I have installed:

<ItemGroup>
  <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.8" />
  <PackageReference Include="Microsoft.AspNetCore.Mvc.Versioning" Version="2.2.0" />
  <PackageReference Include="Swashbuckle.AspNetCore" Version="2.4.0" />
</ItemGroup>

Does anyone see what I might be doing wrong?

Solution

When I created the project, I accidentally included the .vs folder in check in. When I removed it from source control, for whatever reason swagger started working again.

Not sure that the explanation is for this.

Comments

[R. Richards]

Did you check the XML documentation file option in the Output section on the Build tab of the project properties?

[Utkarsh Bais]

Try setting up the root url for swagger

[IfElseTryCatch]

Mine randomly started working again when I deleted the .vs file from the solution in explorer. Although it didn't help that I was getting an error from one of my controllers... I think that may have been the issue...

[Fernando]

Mine as well, it simply started working after deleting the .vs folder. This was driving me crazy.

[Manfred Wippel]

Thank you so much. This helped a lot Every time i set up a project there is something different with the swagger UI

[JensB]

Just ran into this now. Was working perfectly, then all of a sudden it gave 404. Closed VS2017 and removed /.vs folder. Now it works again.

[Karel Kral]

I have run into the same issue with VS 2019. Deleting .vs folder resolves the issue. Unbelievable.