MemberProfileContentFinder.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using umbraco.cms.businesslogic.member;
using Umbraco.Core;
using Umbraco.Web.Routing;
 
namespace MyExampleSite.BusinessLogic
{
    public class MemberProfileContentFinder : IContentFinder
    {
        public bool TryFindContent(PublishedContentRequest contentRequest)
        {
            var urlParts = contentRequest.Uri.GetAbsolutePathDecoded().Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries);
            
            //Check if the Url Parts
            // Starts with /member/*
            if (urlParts.Length > 1 && urlParts[0].ToLower() == "member")
            {
                //Lets try & find the member
                var memberName = urlParts[1];
 
                //Try and find a member where the property matches the memberName
                var tryFindMember = Member.GetAll.SingleOrDefault(x => x.getProperty("profileURL").Value.ToString() == memberName);
 
                //See if tryFindMember is not null
                if (tryFindMember != null)
                {
                    //Need to set the member ID or pass member object to published content
 
 
                    //Set the Published Content Node to be the /Profile node - can get properties off it & my member profile in the view
                    contentRequest.PublishedContent = contentRequest.RoutingContext.UmbracoContext.ContentCache.GetByRoute("/profile");
                }
                else
                {
                    //Need to throw some custom: Not found Member
                    //as opposed to filitering down to other iContentFinders and show the 404
                }
 
                
                //Return true to say found something & stop pipleine & other contentFinder's from running
                return true;
            }
 
            //Not found any content node to display/match - so run next ContentFinder in Pipeline
            return false;
        }
    }
}

How to pass that found member to the pipeline: we don't have a recommended solution at the moment. See http://issues.umbraco.org/issue/U4-61, one suggestion was to implement UmbracoContext.Items so you could do UmbracoContext.Items["myMember"] = member. But we're not there yet.
In the meantime... HttpContext.Current.Items["myMember"] = member. Bit ugly, but it works.