In previous asp.net web api, I implement DefaultHttpControllerSelector to specify how I want the request to locate my controller. I often have different controllers with different names but intended for same processes. The only difference is that one is of higher version than the other.
For example, I could have a controller named BookingV1Controller, which would be meant to handle the version one of the service. I would also have BookingV2Controller, which was designed to handle the version two of the service. A client application would then make a request to the service with this url http://myservice.com/api/v2/booking/someaction?id=12. To handle the request, I would provide a custom implementation of DefaultHttpControllerSelector to select the appropriate version of the controller required based on the requested version.
However, I seems not to have a way to do this in ASP.NET Core. I have searched everywhere to no avail. No documentation that could help either.
I would appreciate if anyone can be of help to me here. Thanks.
UPDATE
I would also like to know what to do if the version is specified in a custom header. E.g X-Version:v1
UPDATE 2
The requirement was that the version of the service should not be exposed in the URL. If no version is present, the service returns with instruction on how to add the version. If a requested controller is not present in the version requested, the system searches through the lower versions. If it finds it in any lower versions, it uses that. The reason for this is to prevent repetition of controllers on all versions. But with ASP.NET Core, this might not be possible.
Answers:
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Method 1
This is a very old question that I stumbled upon, but there are much better solutions now. There is this package
Microsoft.AspNetCore.Mvc.Versioning
Which has a much more feature rich way of implementing versioning controls. These include being able to use URL query strings, url paths, headers, or custom version readers. Being able to read the version from HTTPContext etc.
In short, you add the following into your ConfigureServices method in startup.cs
services.AddApiVersioning(o => {
o.ReportApiVersions = true;
o.AssumeDefaultVersionWhenUnspecified = true;
o.DefaultApiVersion = new ApiVersion(1, 0);
});
Then you have to decorate your controllers with an ApiVersion.
[ApiVersion("1.0")]
[Route("api/home")]
public class HomeV1Controller : Controller
{
[HttpGet]
public string Get() => "Version 1";
}
[ApiVersion("2.0")]
[Route("api/home")]
public class HomeV2Controller : Controller
{
[HttpGet]
public string Get() => "Version 2";
}
You can also implement it in the path by putting it in the route.
[ApiVersion("1.0")]
[Route("api/{version:apiVersion}/home")]
public class HomeV1Controller : Controller
{
[HttpGet]
public string Get() => "Version 1";
}
[ApiVersion("2.0")]
[Route("api/{version:apiVersion}/home")]
public class HomeV2Controller : Controller
{
[HttpGet]
public string Get() => "Version 2";
}
When you go down this method of actually having it implemented via the Microsoft package, it also means that you are able to deprecate versions, have version discovery, access the version number from the HttpContext easily etc. None of which you could really do if it’s just hardcoded in your route.
For more info (Including using it in a header) :
- http://dotnetcoretutorials.com/2017/01/17/api-versioning-asp-net-core/
- http://www.hanselman.com/blog/ASPNETCoreRESTfulWebAPIVersioningMadeEasy.aspx
- https://github.com/Microsoft/aspnet-api-versioning/wiki
Method 2
I created a package for this purpose exactly after banging my head on this problem for a few days. It doesn’t require attributes.
https://github.com/GoAheadTours/NamespaceVersioning
In summary, you can register an IApplicationModelConvention in your startup file that can iterate through controllers and register routes based on the namespaces. I created a v1 folder, and put my controller inside
The class that implements IApplicationModelConvention implements an Apply method with an ApplicationModel parameter that will have access to the Controllers in your app and their existing routes. If I see a controller does not have a route set up in my class I get the version from the namespace and use a pre-defined URL prefix to generate a route for that version.
public void Apply(ApplicationModel application) {
foreach (var controller in application.Controllers) {
var hasRouteAttribute = controller.Selectors.Any(x => x.AttributeRouteModel != null);
if (hasRouteAttribute) {
continue;
}
var nameSpace = controller.ControllerType.Namespace.Split('.');
var version = nameSpace.FirstOrDefault(x => Regex.IsMatch(x, @"[v][d*]"));
if (string.IsNullOrEmpty(version)) {
continue;
}
controller.Selectors[0].AttributeRouteModel = new AttributeRouteModel() {
Template = string.Format(urlTemplate, apiPrefix, version, controller.ControllerName)
};
}
}
I have all the code up on github and a link to the package on nuget as well
Method 3
Use the routing attributes to control versions.
i.e.
[Route("api/v1/[controller]")]
public class BookingV1Controller : Controller
{
....
}
[Route("api/v2/[controller]")]
public class BookingV2Controller : Controller
{
....
}
For more information relating to migrating from standard Web Api and .NET Core ASP.NET have a look at: MSDN: Migrating from ASP.NET Web Api
Method 4
For that Add service API versioning to your ASP.NET Core applications
public void ConfigureServices( IServiceCollection services )
{
services.AddMvc();
services.AddApiVersioning();
// remaining other stuff omitted for brevity
}
QUERYSTRING PARAMETER VERSIONING
[ApiVersion( "2.0" )]
[Route( "api/helloworld" )]
public class HelloWorld2Controller : Controller {
[HttpGet]
public string Get() => "Hello world!";
}
So this means to get 2.0 over 1.0 in another Controller with the same route, you’d go here:
/api/helloworld?api-version=2.0
we can have the same controller name with different namespaces
URL PATH SEGMENT VERSIONING
[ApiVersion( "1.0" )]
[Route( "api/v{version:apiVersion}/[controller]" )]
public class HelloWorldController : Controller {
public string Get() => "Hello world!";
}
[ApiVersion( "2.0" )]
[ApiVersion( "3.0" )]
[Route( "api/v{version:apiVersion}/helloworld" )]
public class HelloWorld2Controller : Controller {
[HttpGet]
public string Get() => "Hello world v2!";
[HttpGet, MapToApiVersion( "3.0" )]
public string GetV3() => "Hello world v3!";
}
Header Versioning
public void ConfigureServices( IServiceCollection services )
{
services.AddMvc();
services.AddApiVersioning(o => o.ApiVersionReader = new HeaderApiVersionReader("api-version"));
}
When you do HeaderApiVersioning you won’t be able to just do a GET in your browser, so I’ll use Postman to add the header (or I could use Curl, or WGet, or PowerShell, or a Unit Test):
please refer https://www.hanselman.com/blog/ASPNETCoreRESTfulWebAPIVersioningMadeEasy.aspx
All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0