PerUserCacheKeyGenerator.cs

using System.Collections.Generic;
using System.Net.Http.Headers;
using System.Web.Http.Controllers;

namespace WebApi.OutputCache.V2
{
    public class PerUserCacheKeyGenerator : DefaultCacheKeyGenerator
    {
        public override string MakeCacheKey(HttpActionContext context, MediaTypeHeaderValue mediaType, bool excludeQueryString, Dictionary<string, List<string>> headers)
        {
            var baseKey = MakeBaseKey(context);
            var parameters = FormatParameters(context, excludeQueryString);
            var userIdentity = FormatUserIdentity(context);
            string custHeaders = GetCustomHeaders(headers);

            if (!(string.IsNullOrEmpty(custHeaders)))
                return string.Format("{0}{1}:{2}:{3}:{4}", baseKey, parameters, custHeaders, userIdentity, mediaType);
            else
                return string.Format("{0}{1}:{2}:{3}", baseKey, parameters, userIdentity, mediaType);
        }

        protected virtual string FormatUserIdentity(HttpActionContext context)
        {
            return context.RequestContext.Principal.Identity.Name.ToLower();
        }
    }
}