IHttpHandler实现

Question

so I am trying to create a situation that allows us to test two versions of a portion of our application randomly. I've created an implementation of the IHttpHandler (C#, asp.net webforms 4, website project) and when a request comes in for our 'shop', I evaluate whether or not they should see shop or shopB.

Here's the implementation of the handler:

public class ShopRequestHandler : IHttpHandler, IReadOnlySessionState
    {
        public ShopRequestHandler() { }

        public void ProcessRequest(HttpContext context)
        {
            var originalRequest = context.Request.RawUrl;
            var process = originalRequest.Contains("shop");
            if (process)
            {
                if (UsingShopB(context))
                {
                    var newRequest = originalRequest.Replace("shop", "shopB");
                    context.Response.Redirect(newRequest, false);
                }
                else
                {
                    context.Response.Redirect(originalRequest, false);
                }
            }

        }
        public bool IsReusable
        {
            get { return false; }
        }

        private bool UsingShopB(HttpContext context)
        {
            HttpCookie cookie = context.Request.Cookies["UseShopB"];
            if (cookie == null)
            {
                var rand = new Random();
                var val = rand.Next(1, 10);
                context.Response.AppendCookie(val%2 == 0
                    ? new HttpCookie("UseShopB", true.ToString())
                    : new HttpCookie("UseShopB", false.ToString()));
            }
            var httpCookie = context.Response.Cookies["UseShopB"];
            return httpCookie != null && Boolean.Parse(httpCookie.Value);
        }
    }

The problem is not with redirecting to shop b, that works great. It's really just when I want the regular version of shop. I get a crazy request loop and an error saying that the page cannot be displayed. It seems to me that I'm not really doing anything different when shop is requested. It's when shopB is requested that modifications happen. Stumped. Should I not be using RawUrl? What am I missing? This is a production problem so any help would be huge. and just to re-iterate, when the random choice is shopB it works perfectly. grrr.

I just wanted to add that when I modify the path everything works fine, what I need help with is how to leave the original request alone when I don't need to modify anything. Help!

Thank you -Sean

Answer 1

The problem is with the check you've placed for Shop:

var process = originalRequest.Contains("shop")

This will be true for both "Shop" and "ShopB" so in case of Shop it will return "ShopB" but in case of ShopB it'll returned "ShopBB"

you need more refined check for this filter. Either reverse the check or use exact match with word count.