.Net 6 Web Api Swagger Versioning problem - swagger

Question

As the title suggests, i have a .net 6 web api that I'm trying to add versioning to but swagger (swashbuckle) does not seem to understand whats going on.
Program.cs
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Versioning;
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddApiVersioning(setup =>
{
setup.DefaultApiVersion = new ApiVersion(1, 0);
setup.AssumeDefaultVersionWhenUnspecified = true;
setup.ReportApiVersions = true;
});
ConfigureServices(builder.Services);
var app = builder.Build();
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.UseSwagger();
app.UseSwaggerUI(c =>
{
c.SwaggerEndpoint($"/swagger/v1/swagger.json", $"v1");
c.SwaggerEndpoint($"/swagger/v2/swagger.json", $"v2");
});
app.Run();
void ConfigureServices(IServiceCollection services)
{
services.AddMvcCore();
services.AddApiVersioning(options =>
{
options.ReportApiVersions = true;
options.AssumeDefaultVersionWhenUnspecified = false;
options.ApiVersionReader = new UrlSegmentApiVersionReader();
});
services.AddSwaggerGen();
}
I have annotated my controllers like so:
[ApiVersion("1.0")]
[Route("api/v1/[controller]")]
[ApiController]
public class MessageController : ControllerBase
[ApiVersion("2.0")]
[Route("api/v2/[controller]")]
[ApiController]
public class MessageController : ControllerBase
The swagger document that is generated looks like this:
And if i select v2 from the drop down, I get this:
Nuget packages and versions installed are:
Can anyone tell me where I'm going wrong.

Answer 1

You'll need to add the swagger documents themselves, not just the UI for them. In your AddSwaggerGen method, add something like:
services.AddSwaggerGen(c => {
c.SwaggerDoc("v1", new OpenApiInfo { Version = "v1", Title = "My API" });
c.SwaggerDoc("v2", new OpenApiInfo { Version = "v2", Title = "My API" });
});

Answer 2

This article seems to have covered all the aspect what you are looking for.
Please have a look.
https://referbruv.com/blog/integrating-aspnet-core-api-versions-with-swagger-ui/

Answer 3

Besides passing the configuration here:
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new OpenApiInfo { Title = "My API - V1", Version = "v1" });
c.SwaggerDoc("v2", new OpenApiInfo { Title = "My API - V2", Version = "v2" });
});
According to the docs you have to specify the GroupName of the controller:
[ApiVersion("2.0")]
[Route("api/v2/[controller]")]
[ApiController]
[ApiExplorerSettings(GroupName = "v2")]
public class MessageController : ControllerBase
Also, the docs show ways to customize and add conventions.