aspnet-api-versioning - backward compatibility - asp.net

Question

I need to сlarify.
I have .net mvc app and I use Microsoft/aspnet-api-versioning (for ASP.NET Core).
And I have 2 controllers:
[ApiVersion("1.0")]
[Route("[controller]")]
public class OneController : Controller
{
[HttpGet]
public string Get()
{
return "Hello. I'm OneController";
}
}
and
[ApiVersion("1.1")]
[Route("[controller]")]
public class TwoController : Controller
{
[HttpGet]
public string Get()
{
return "Hello. I'm TwoController";
}
}
TwoController I added after release API with OneController.
And now if I try to use "http://localhost:59719/One?api-version=1.1" i see error:
The HTTP resource that matches the request URI 'http://localhost:59719/test?api-version=1.1' does not support the API version '1.1'.
Should I use different versions for different controllers or there is way to use one (latest) version for any request?
I understand I can add [ApiVersion("1.1")] to ALL controllers, but if I have 20 controllers...
Thanks for help.

Answer 1

You can define a default api version using the ApiVersioningOptions class and use this default version if none is specified:
`services.AddApiVersioning(o =>
{
o.AssumeDefaultVersionWhenUnspecified = true;
o.DefaultApiVersion = new ApiVersion(1 , 0);
});`
Besides, you should take a look at this excellent post on API versioning in ASP.NET from Scott Hanselman:
https://www.hanselman.com/blog/ASPNETCoreRESTfulWebAPIVersioningMadeEasy.aspx

Answer 2

In your example above, you have two different controllers with two different API versions. There is no direct relationship between these two. If you're trying to apply API versions in a centralized manner, you can achieve this using the Conventions API. You can even author and apply your own conventions via the IControllerConvention interface.
// same result as the attributes above
options.Conventions.Controller<OneController>().HasVersion(1,0);
options.Conventions.Controller<TwoController>().HasVersion(1,1);
// can also be achieved using only controller types
options.Conventions.Controller(typeof(OneController)).HasVersion(1,0);
options.Conventions.Controller(typeof(TwoController)).HasVersion(1,1);
// register your own convention that applies API versions to all controllers
options.Conventions.Add(new MyCustomApiVersionConvention());
You can also use an approach similar to what #arnaudauroux suggested, which would be:
services.AddApiVersioning(options =>
{
options.AssumeDefaultVersionWhenUnspecified = true;
options.ApiVersionSelector = new CurrentImplementationApiVersionSelector(options);
});
Now any request without an API version will select the current (or highest) API version available. Beware that this could break clients.