Customize MapHttpAttributeRoutes for Web Api Versioning

Question

I am implementing Web API versioning as in Web API Versioning. My controllers are in 2 separate namespaces, and I\'ve used a custom SelectController method to choose which versi

Answer 1

I extended Michael Brown's answer to allow setting a default version:

Only now I'm thinking how to make it work with Swashbuckle swagger.

RouteVersionAttribute:

using System.Collections.Generic;
using System.Web.Http.Routing;

namespace YourNameSpace.Filters
{
    /// 

    /// Here is a solution that will let you use the Web API 2 way of versioned routes (headers),
    /// in addition to query parameter support (i.e.use a header called 'api-version' or 
    /// a querystring parameter named '?api-version=XXX'.
    /// https://stackoverflow.com/a/28934352/3187389
    /// https://stackoverflow.com/questions/25299889/customize-maphttpattributeroutes-for-web-api-versioning
    /// 
    public class RouteVersionAttribute : RouteFactoryAttribute
    {
        public int Version { get; private set; }
        public int VersionDefault { get; private set; }

        public RouteVersionAttribute() : this(null, 1, true)
        {
        }

        /// 

        /// Specify a version for the WebAPI controller or an action method
        /// for example: [RouteVersion("Test", 1)] or [RouteVersion("Test", 1, true)]
        /// 
        /// 
        /// 
        public RouteVersionAttribute(int version, bool isDefault = false) : this(null, version, isDefault)
        {
        }

        /// 

        /// Specify a version for the WebAPI controller or an action method
        /// for example: [RouteVersion("Test", 1)] or [RouteVersion("Test", 1, true)]
        /// 
        /// 
        /// 
        /// 
        public RouteVersionAttribute(string template, int version, bool isDefault = false)
            : base(template)
        {
            Version = version;
            if (isDefault)
                VersionDefault = version;
        }

        public override IDictionary Constraints
        {
            get
            {
                var constraints = new HttpRouteValueDictionary();
                constraints.Add("version", new RouteVersionHttpConstraint(Version, VersionDefault));
                return constraints;
            }
        }

        public override IDictionary Defaults
        {
            get
            {
                var defaults = new HttpRouteValueDictionary();
                defaults.Add("version", VersionDefault);
                return defaults;
            }
        }
    }
}

RouteVersionHttpConstraint:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Web.Http.Routing;

namespace Boyd.Core.Filters
{
    /// 

    /// Here is a solution that will let you use the Web API 2 way of versioned routes (headers),
    /// in addition to query parameter support (i.e.use a header called 'api-version' or 
    /// a querystring parameter named '?api-version=XXX'.
    /// https://stackoverflow.com/a/28934352/3187389
    /// https://stackoverflow.com/questions/25299889/customize-maphttpattributeroutes-for-web-api-versioning
    /// 
    public class RouteVersionHttpConstraint : IHttpRouteConstraint
    {
        public const string VersionHeaderName = "api-version";
        private readonly int VersionDefault = 1;

        /// 

        /// Add a route constraint to detect version header or by query string
        /// 
        /// 
        public RouteVersionHttpConstraint(int allowedVersion, int versionDefault)
        {
            AllowedVersion = allowedVersion;
            VersionDefault = versionDefault;
        }

        public int AllowedVersion
        {
            get;
            private set;
        }

        /// 

        /// Perform the controller match
        /// 
        /// 
        /// 
        /// 
        /// 
        /// 
        /// 
        public bool Match(HttpRequestMessage request, IHttpRoute route, string parameterName, IDictionary values, HttpRouteDirection routeDirection)
        {
            if (routeDirection == HttpRouteDirection.UriResolution)
            {
                int version = GetVersionHeaderOrQuery(request) ?? VersionDefault;
                if (version == AllowedVersion)
                {
                    return true;
                }
            }
            return false;
        }

        /// 

        /// Check the request header, and the query string to determine if a version number has been provided
        /// 
        /// 
        /// 
        private int? GetVersionHeaderOrQuery(HttpRequestMessage request)
        {
            string versionAsString;
            if (request.Headers.TryGetValues(VersionHeaderName, out IEnumerable headerValues) 
                && headerValues.Count() == 1)
            {
                versionAsString = headerValues.First();
                if (versionAsString != null && Int32.TryParse(versionAsString, out int version))
                {
                    return version;
                }
            }
            else
            {
                var query = System.Web.HttpUtility.ParseQueryString(request.RequestUri.Query);
                string versionStr = query[VersionHeaderName];
                int.TryParse(versionStr, out int version);
                if (version > 0)
                    return version;
            }
            return null;
        }
    }
}

Usage (can be used on the controller or action methods):

#region Temporary Tests

// {{BaseUrl}}Test?api-version=1

[HttpGet]
[RouteVersion("Test", 1)]
public async Task Test1([FromBody]GetCustomerW2GsForPropertyRequest request)
{
    return await Task.FromResult(Ok("API Version 1 selected"));
}

[HttpGet]
[RouteVersion("Test", 2)]
[RouteVersion("Test", 3)]
[RouteVersion("Test", 4)]
public async Task Test4([FromBody]GetCustomerW2GsForPropertyRequest request)
{
    return await Task.FromResult(Ok("API Version 2, 3 or 4 selected"));
}

[HttpGet]
[RouteVersion("Test", 5, true)]
public async Task Test5([FromBody]GetCustomerW2GsForPropertyRequest request)
{
    return await Task.FromResult(Ok("API Version 5 selected"));
}

#endregion Temporary Tests