Designing Business Objects for web2.0 Applications

When we sit down at the beginning of the process to design our brand new shiny web2.0 application (Please, not another social network...) we should consider several issues regarding Object Oriented design in general, as well as web2.0 application specifically.

Find your objects
This is true for every program. First thing to do is read the product specification (if working in medium or large company) or just describe the system in words. Notice the objects in your sentences as candidates for being objects in the system. For each one ask yourself: "Does it contain any information i should use?" This Information is the object properties. "What actions can this object perform?" leads to a list of methods. Objects on the list that have no properties or methods should not be objects in the system.

Remember the Channels
When selecting parameters for the methods and types for the properties remember who is on the other side. Is that a web page calling? A web service? Some Embedded code from this blog?
What are they asking for? What language do they speak?
You may consider writing a Data Access Layer that speaks SQL with the database and sends DataSet objects to the Business Objects. The business objects receive requests from Server-Side code that runs inside a web server. Those requests use a certain textual format to pass data to the server. Simple applications may send single values over Query Strings, but any real application should use JSON or XML as a data protocol with the web client. On this web client you may like to have some cool AJAX controls to smooth the User Experience, So you will need a set of Client-Side objects, written usually in Javascript.

Design Serializable Objects
If you are using JSON or XML you should design your objects to be serializeable. That means using only string, int, bool, object and array as the types of your properties. Any JSON Serializer can read such objects and this saves you iterating through all the object properties to read it's values. You just write something like MyJSONString = Serializer.Serialize(MyObject) and Bam! you got yourself a JSON string to send back to the browser.

Match Server and Client Objects
Since we have two sets of objects, one on the server and one on the client, we should match their properties to allow for smooth data transfer. There are JSON and XML serializers in javascript too, of course. You can avoid this problem all together by using a Library planned for this purpose like the Microsoft Ajax Extensions 1.0. Take a look but be careful, this package is only for professionals. It requires the best understanding of Internet technologies and much patience for Microsoft heavy object models.

Plan Great Utilities
Well, What do we do with all this? We can start by writing a set of utilities that will simplify our coding and will make the application more robust. One function we should write is a generic DataSet2Object function, that reads a dataset and returns a collection of the desired objects. There may be some others, but you get the idea.

Remember to breath :)

Benny.

Creating and Submitting a Sitemap to Google

As many know, Google search results are based on a crawler software that surfs our sites like a regular user, more or less. If for some reason we have pages on our site that are not linked from any other page, they will not appear in search results. In order to improve google's crawling in our site we should send google a link to an Xml file that we create in our site, and in this file we can list all the site's pages that we want Google to show in his search results. This file is called a Sitemap.

If a site is made of static pages, you just write them down in your file and you are done. All you need to do now (After submitting the Sitemap, of course) is to update the file with any new pages that you create. If, on the other hand, you are running a dynamic site that pulls it's pages out of a database, you have more work to do.

First, you need to create a Permalink for every page. Permalink is a static Url, without ? and parameters in the Url. You can use any unique value for that, like product name or page title.
A permalink can look like this: http://www.5min.com/Video/What-is-5min%20XH9DUGl7fO8%3d.
Then you need to generate the sitemap from a server page. You can use the XmlDocument object model to build the correct Xml file format. I suggest that you use an HttpHandler for this task, but any Asp page will do as well. All you need to do is to write the Xml file into the Http Response object.

Now that you have the Sitemap ready, you have to submit it to google as your Sitemap. For this you have to register to the Google Webmaster Tool service. If you already have a Google account then it's enough. There you have simple instructions how to submit your Sitemap. You can submit many sites and see how google reads them and more statistics.

You can find good information on Sitemaps at http://www.sitemaps.org/.
An already-made c# Sitemap class can be found here.

Please comment with your opinion on this post.

Benny.