Sometimes you need to resolve relative url’s without ResolveUrl. If the code is executing outside a Control, for example in an IHttpHandler or business layer code somewhere that has no reference to a Control, you can’t call Control.ResolveUrl.
The System.Web.VirtualPathUtility class has some very useful method for converting from an app relative path to an absolute path:
string absoluteUrl = VirtualPathUtility.ToAbsolute(relativeUrl);
As I alluded in a post a couple of weeks ago, I have been a bad blogger. And I have neglected my community of readers. However I would like to tell you what I have been doing in the last couple of months while I have been neglecting my blog.
I recently got involved in creating a startup as the lead developer for an online classifieds site called Anything For Sale By Owner. From the ground up this was conceived as a middle-ground between craigslist and ebay where every listing would be charged at a static rate of $1.00/month. The $1.00 is a way to week out the crap from craigslist and the death-by-fees from ebay.
The description is pretty straight forward but the more interesting tid-bits that I know my readers are interested in are as follows:
.NET/C#
We choose .NET mostly because it is what I knew and .NET for me has always been stable, predictable, and performed really well on server-side applications. The alternative was PHP and even through we wrote many of the processing layers by our self (i.e. REST Web Service Handler) the time to deployment was greatly accelerated because of all the work the Microsoft ASP.NET Team has put in to the product. The user of Master Pages and Web Services made for an easy separation between content and display.
MySQL
We choose MySQL for a whole host of reasons mostly based around the costs associated with a single Microsoft SQL Server Standard Edition license. Other reasons we choose MySQL was for scalability, because not only could we install 5 database servers (hardware included) for the same price we could purchase 1 MSSQL database server for but also because the master/slave replication of the databases seemed to be an easier process when we needed to scale horizontally.
REST Web Services/AJAX
We followed the Digg Model for exposing web services and each web service could be changed around to provide output through JSON, RSS, ATOM, KML (where applicable), and XML. I even did a write up about a month ago on the JSON Serializer that I developed for this website. This was very important for the AJAX we needed to control many aspects of the user experience.
Open Search
Open search was one of the value add features that wasn’t in the original spec but was an easy add-on because we already had the Web Services in place to leverage. You can view our open search XML definition file here. If you are unfamiliar with Open Search this is how A9.com defines it:
OpenSearch is a set of simple formats for the sharing of search results. Any website that has a search feature can make their results available in OpenSearch format. Other tools can then read those search results.
So that little search box in the upper right hand corner of your browser is an example of an Open Search client.
SEO
Search Engine Optimization is a very important part of any website today. Because for most new sites and even some of the older ones, Google is going to be the largest most ignored user of the site. Not only will Google look at every single page on your site every week, which I dare any human to try and accomplish, they will also be the largest organic promoter of your site.
One of the corner stones of SEO is easily readable URL’s that contain descriptive keywords. This means you have to have a good URL Rewriter in place. We choose Ionic’s ISAPI Rewriter that integrated nicely with IIS 6.0. However that left a big gap between using Visual Studio’s Intigrated Web Server (which doesn’t support ISAPI) and a full blown IIS Server. The benifits are pretty obvious for running the Intigrated Web Server that comes with Visual Studio, for one you don’t always have to have IIS that comes with Windows XP always running and the host of security problems that comes with it, two I was running Windows Vista and IIS 7.0 has some huge differences from IIS 6.0.
So I sat down one night and wrote my own Apache mod_rewrite compatible HttpModule for running the same rule-set that I defined for Ionic’s ISAPI Rewriter, to fill in the gap and make developing on my local machine as close as running the live web site on IIS 6.0.
If anybody is interested I offer the Url Rrewriter as a free download:
Front End Design
I am a software developer and usually don’t get invovled in the artsy end of the web site design. So I will let my co-worker Tom Lauck describe how he developed the front-end for Anything For Sale By Owner.
So all in all I believe that this website has a very good chance of making in the Wild Wild West that the Internet is, however that is probably just the ramblings of a proud father. Be on the look out for some major marketing campaigns in the NYC Times Square region.
Recently I have been diving in to the world of REST and all the great things that come along with that. If you are not familiar with REST and what it means to have a REST Web Service for your site, you can go through the Digg API, which should give you a pretty good idea. My company has been contracted to build the framework for a new Web 2.0 initiative of one of our clients. You cannot do Web 2.0 if you are not using some kind of AJAX/REST combination.
With the inclusion of Microsoft AJAX.NET are some very useful tools that have been added to the web services library. My current focus in System.Web.Script.Serialization.JavaScriptSerializer, which takes you objects and turns them in to a JSON string that can be evaluated by JavaScript and reversed in to an object. JSON (pronounced Jason) is very useful in AJAX because you do not have to retrieve and parse XML through the XML Browser Request that powers current AJAX implementations.
I found the attribute support lacking in the JavaScriptSerializer when compared to the XmlSerializer, ScriptIgnoreAttribute compared to XmlRootAttribute, XmlAttributeAttribute, XmlIgnoreAttribute, XmlElementAttribute, XmlArrayAttribute, and XmlArrayItemAttribute. So I decided to extend the JavaScriptSerializer to use the XML attributes to serialize my objects and give me greater control over how they were written in to JSON text form. The added benefit was that my XML and JSON outputs serialized the exact same way when the web service generated them. Below I have included the code.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Reflection;
using System.Web.Script;
using System.Web.Script.Serialization;
using System.Xml.Serialization;
namespace ManagedFusion.Script.Serializer
{
public class XmlJavaScriptConverter<T> : JavaScriptConverter
{
public override object Deserialize(IDictionary<string,string> dictionary, Type type, JavaScriptSerializer serializer)
{
throw new Exception("The method or operation is not implemented.");
}
public override IDictionary<string,string> Serialize(object obj, JavaScriptSerializer serializer)
{
return SerializeObject(obj);
}
private IDictionary<string,string> SerializeObject(object obj)
{
IDictionary<string,string> values = new Dictionary<string,string>();
Type type = obj.GetType();
foreach (FieldInfo info in type.GetFields(BindingFlags.Public | BindingFlags.Instance))
if (!info.IsDefined(typeof(XmlIgnoreAttribute), true))
values.Add(SerializeName(info), SerializeValue(info.GetValue(obj), info));
foreach (PropertyInfo info2 in type.GetProperties(BindingFlags.GetProperty | BindingFlags.Public | BindingFlags.Instance))
{
if (!info2.IsDefined(typeof(XmlIgnoreAttribute), true))
{
MethodInfo getMethod = info2.GetGetMethod();
if ((getMethod != null) && (getMethod.GetParameters().Length <= 0))
values.Add(SerializeName(info2), SerializeValue(getMethod.Invoke(obj, null), info2));
}
}
return values;
}
private string SerializeName(MemberInfo member)
{
string name = null;
if (member.IsDefined(typeof(XmlElementAttribute), true))
{
object[] attrs = member.GetCustomAttributes(typeof(XmlElementAttribute), true);
if (attrs.Length > 0)
{
XmlElementAttribute attr = attrs[0] as XmlElementAttribute;
name = attr.ElementName;
}
}
if (member.IsDefined(typeof(XmlAttributeAttribute), true))
{
object[] attrs = member.GetCustomAttributes(typeof(XmlAttributeAttribute), true);
if (attrs.Length > 0)
{
XmlAttributeAttribute attr = attrs[0] as XmlAttributeAttribute;
name = attr.AttributeName;
}
}
if (member.IsDefined(typeof(XmlArrayAttribute), true))
{
object[] attrs = member.GetCustomAttributes(typeof(XmlArrayAttribute), true);
if (attrs.Length > 0)
{
XmlArrayAttribute attr = attrs[0] as XmlArrayAttribute;
name = attr.ElementName;
}
}
if (String.IsNullOrEmpty(name))
name = null;
return name ?? member.Name;
}
private object SerializeValue(object obj, MemberInfo member)
{
if (obj == null)
return obj;
// make sure the object isn't an easily handled primity type
if (Type.GetTypeCode(obj.GetType()) != TypeCode.Object)
return obj;
if (obj is IDictionary)
return obj;
if (obj is ICollection)
{
IList<object> list = new List<object>();
object[] attrs = member.GetCustomAttributes(typeof(XmlArrayItemAttribute), true);
string arrayName = null;
if (attrs.Length > 0)
{
XmlArrayItemAttribute attr = attrs[0] as XmlArrayItemAttribute;
arrayName = attr.ElementName;
}
if (String.IsNullOrEmpty(arrayName))
{
foreach (object o in (obj as ICollection))
{
if (Type.GetTypeCode(o.GetType()) != TypeCode.Object)
list.Add(o);
else
list.Add(SerializeObject(o));
}
}
else
{
foreach (object o in (obj as ICollection))
{
IDictionary<string,object> list2 = new Dictionary<string,object>();
if (Type.GetTypeCode(o.GetType()) != TypeCode.Object)
list2.Add(arrayName, o);
else
list2.Add(arrayName, SerializeObject(o));
list.Add(list2);
}
}
return list;
}
return SerializeObject(obj);
}
public override IEnumerable<Type> SupportedTypes
{
get { return new ReadOnlyCollection<Type>(new List<Type>(new Type[] { typeof(T) })); }
}
}
}
Then to serialize the object in my code I have the following code in place.
JavaScriptSerializer jsSerializer = new JavaScriptSerializer();
jsSerializer.RegisterConverters(new List<JavaScriptConverter>(new JavaScriptConverter[] { new XmlJavaScriptConverter<T>() }));
string response = jsSerializer.Serialize(SerializableObject);
The serializer from above outputs the following code.
{"timestamp":"\/Date(1187968133328)\/","maxCount":10,"count":1,"terms":[{"term":"dvd hollywood"}]}
From this object as the reference.
[XmlRoot("search")]
public class GetTermsResponse
{
private string[] _terms;
private int _maxCount;
[XmlAttribute("timestamp")]
public DateTime TimeStamp
{
get { return DateTime.Now; }
set { ; }
}
[XmlAttribute("maxCount")]
public int MaxCount
{
get { return _maxCount; }
set { _maxCount = value; }
}
[XmlAttribute("count")]
public int Count
{
get { return Terms.Length; }
set { ; }
}
[XmlArray("terms")]
[XmlArrayItem("term")]
public string[] Terms
{
get { return _terms; }
set { _terms = value; }
}
}
So that wasn’t too hard the next step for this code is to make it so it can deserialize the JSON string back to an object, but the chances of that happening are almost 100/1 against the use of that functionality, because POST using JSON is a very dangerous activity and shouldn’t be attempted unless you know all the problems that may occur. So this code above should work in most real world examples. Happy coding.
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