VersionedRoute Attribute Implementation for MVC6

Question

I am trying to enable versioning on a REST API, where the version is specified in the header, as "api-version":2.

According to this tutorial I just need to create

VersionConstraint : IHttpRouteConstraint

and

VersionedRoute: RouteFactoryAttribute

The usage would be to apply the [VersionedRoute("api/controllerName", 2)] Attribute to Controllers, which are designed for specific versions (e.g. version 2 in this case).

This is all good and well, but unfortunately, it's all in MVC5 and I'm using MVC6. Therefore, RouteFactoryAttribute and IHttpRouteConstraint don't work.

I managed to find IRouteConstraint to replace IHttpRouteConstraint (hoping it will work), but I cannot find a replacement for RouteFactoryAttribute.

If anyone can provide a sample of this using MVC 6, or at least mention the correct classes (ideally with namespaces) I need to inherit from?

Answer 1

Here's the minimum amount of work you need.

First, go there and copy the code for the 3 following files:

• VersionGetAttribute
• VersionRangeValidator
• VersionRoute.cs

Once you have this, we'll change the GetVersion method of VersionRangeValidator for the following:

public static string GetVersion(HttpRequest request)
{
    if (!string.IsNullOrWhiteSpace(request.Headers["api-version"]))
        return request.Headers["api-version"];

    return "1";
}

That will read the header and return the API version. The default will be v1 in this scenario.

Here's how to use it on controllers (or it can be the same controllers with 2 actions:

[Route("api/data")]
public class DataController 
{
    [VersionGet("", versionRange: "[1]")]
    public string GetData()
    {
        return "v1 data";
    }
}

[Route("api/data")]
public class DataV2Controller 
{
    [VersionGet("", versionRange: "[2]")]
    public string GetData()
    {
        return "v2 data";
    }
}

So now you just need to give it the right header and it's good. This code has been tested with jQuery like this:

$(document).ready(function(){
    $.ajax({url: '/api/Data/', headers: { 'api-version': 1 }})
    .then(function(data){
            alert(data);
            });
    $.ajax({url: '/api/Data/', headers: { 'api-version': 2 }})
    .then(function(data){
            alert(data);
            });
});