Custom Item Resolver and the Hidden Query String

Custom Item Resolver and the Hidden Query String

Have you ever tried to troubleshoot an instance where a URL looks something like /ILike/Pizza , but when you drilled down to it in the content tree, there is no Pizza under the ILike item Don t panic! Your pizza will be found! More than likely you are working with a custom item resolver. In other words there is a class somewhere else that is interpreting Pizza as its own value and sending it back as a query string. The user sees /Ilike/Pizza but your code will see /Ilike?myval=Pizza .

A custom item resolver will be a class that will inherit from the HTTPRequestProcessor and is added to the pipeline as something like this:

Here are the guts of the class:

public class ILikeItemResolver : HttpRequestProcessor
    {
        public override void Process(HttpRequestArgs args)
        {
            Assert.ArgumentNotNull(args, "args");
            if (((Context.Item == null) && (Context.Database != null)) && !string.IsNullOrWhiteSpace(args.Url.ItemPath))
            {
                string qsValue = string.Empty;
                string decodedItemName = MainUtil.DecodeName(args.Url.ItemPath);

                string myVal = ResolveBlogItemPath(decodedItemName, "{0}/ILike/{1}", out qsValue);
                
                if (!string.IsNullOrEmpty(myVal))
                {
                    if (myVal != null)
                    {
                        NameValueCollection nv = StringUtil.ParseNameValueCollection(args.Url.QueryString, '&', '=');
                        nv.Add("myval", qsValue);
                        
                        args.Url.QueryString = StringUtil.NameValuesToString(nv, "&");
                    }
                }
            }
        }

        private string ResolveBlogItemPath(string decodedItemName, string urlPattern, out string qsValue)
        {
            qsValue = string.Empty;
            try
            {
                string pattern = urlPattern.FormatWith(@"(^.+)", @"(.+)/$");
                Match match = Regex.Match(StringUtil.EnsurePostfix('/', decodedItemName), @pattern, RegexOptions.IgnoreCase);

                if (match.Success)
                {
                    qsValue = WebUtil.UrlEncode(match.Groups[2].Value);
                    return match.Groups[1].Value;
                }

            }
            catch (Exception ex)
            {
                Log.Error("ILikeItemResolver failed to resolve!", ex, new object());
            }
            return string.Empty;
        }
    }

Here is what the class does:

1. Gathers the current HttpRequestargs item path.
2. Attempts to match that path against our string of {0}/ILike/{1} .
3. If a match is found the value on the right is returned. In our instance that would be Pizza .
4. Finally that value is added to our NameValueCollection and returned as part of the query string.

From here I would probably search for the Pizza item in my data folder, maybe call a web service with it, or just use the value as string. You could also consider extending the logic in your class to do the item or service call automatically. I would take it as a case by case scenario.