ASP.NET: Supporting Dynamic Applications

Introduction

The ASP.NET membership feature reduces the amount of code you have to write to authenticate users and store their credentials. To quote MSDN:

“The ASP.NET membership gives you a built-in way to validate and store user credentials. You use the ASP.NET membership with Forms authentication and / or with the ASP.NET login controls for authenticating users.”

The membership provider needs to be specified in the Web.config configuration file. You can use your own custom provider or one of the default providers that ships with the .NET Framework, such as the SqlMembershipProvider provider.

All of the user related data is stored in a set of tables used by the ASP.NET membership system. In most cases you’ll use one set of tables per web application. However you can also reuse the same set to store the user credentials of multiple web applications. This effectively enables you to create one web application that acts as a portal allowing you to log in to one of these “virtual” applications.

However this isn’t possible out of the box. You have some work ahead of you, before you can support such dynamic applications.

Let’s get started…

Using WCF Services With PHP 5

Introduction

Most of the time when I need to consume a web service I do so using a .NET client built upon the Windows Communication Foundation (WCF). In most cases the web service in question has also been developed using .NET’s WCF.

About 8 years ago I used PHP as my primary tool for building web sites. At the time I used versions 3 & 4. Recently I had the opportunity to brush up my PHP skills by building a couple of small sites using PHP 5. Besides lending itself more towards object orientend programming I noticed that they added support for SOAP by adding the SoapClient class.

As PHP is still widely used it is not unimaginable, but likely very probably that PHP developers out there need to consume a web service that has been developed with WCF. This article explains how to create WCF services that offer support for PHP clients and how such clients can consume these services.

Let’s start coding…

Monitoring A Directory

Introduction

The subject of this article is a tad less modern than the previous two articles: WCF over HTTPS & MEF. Instead of focusing on a modern technology such as WCF or the upcoming Managed Extensibility Framework, I have a craving to write an article about the good ol’ FileSystemWatcher Class.

It’s been around since .NET 1.0 but the other day when I was composing the article about MEF it was brought back to my attention. MEF contains a DirectoryCatalog type, which allows you to specify a directory that contains assemblies that in turn contain extensions (exports) for your application.

In an earlier preview of MEF the DirectoryCatalog type automatically detected new assemblies placed inside of this directory and refreshed the loaded extensions. However this functionality has been dropped in favor of a Refresh() method which you have to call yourself. In other words you are now responsible for detecting new additions to said directory.

The main focus of this article is on how to use the FileSystemWatcher class type effectively for monitoring a directory for new, incoming files. Enough introductionary chit-chat, let’s get to the meat of it…

.NET 4.0: Managed Extensibiliy Framework (MEF)

Introduction

Yesterday, on a sunny sunday morning I was catching up on some blog reading. One post in particular caught my eye, namely A Whirlwind Tour Through The Managed Extensibility Framework by Bart De Smet.

The Managed Extensibility Framework, or MEF, is a new library that will eventually be part of the .NET 4.0 Framework. It enables you to easily create extensible applications that support a plugin model. A lot of modern, popular applications such as FireFox, Winamp, Visual Studio…etc. already provide a plugin / add-in model that allows you to add your own plugins if you want to extend the functionality of the application.

Making your application extensible in the past was certainly possible but you had to create the infrastructure from scratch. Well, no more! MEF allows you to expose certain parts of your application in which you can import built-in or external extensions.

Let’s discover the wonderful world of MEF by building a demo application…

WCF over HTTPS

Introduction

A couple of weeks ago I was asked to write a web service that needed to provide a single operation (method) that allowed the user to upload a file using a Secure Sockets Layer (SSL / HTTPS) .

Although they changed their minds and went for a solution using a VPN connection, I still decided to create the web service in case they went back on their decision again.

This article outlines the steps you need to follow in order to create a service to upload a file over HTTPS using WCF. And it’s been quite a while since I wrote my last article for this blog. I figured this would make an interesting topic…

Live Mesh: Programming against the Live Framework

Introduction

In March I went to the Microsoft TechDays in Belgium. The last session I attended was about Microsoft’s Live Services and the Live Framework used for programming against these services. To showcase all this the Live Mesh service was used.

Live Mesh allows you to easily synchronize files with all of your devices. I tend to visualize it as an online hard drive or repository where I can deposit files which I wish to share amongst my devices such as my laptop at work, my PDA…etc.

You simply have to sign up for a Mesh account and install the Live Mesh client on the devices you want to synchronize. Once the client has been installed all that remains is to add a local folder to Live Mesh. The client will then make sure this folder is synchronized automatically between all of your devices.

Your Live Mesh account allows you to manage the connected devices and Live Mesh folders. For example you can opt to choose between which devices you want to synchronize a certain folder.

When you place a new file into a Live Mesh folder, the client will upload this file to your online Mesh account. The clients on your other devices will be notified as soon as they are up and running and will synchronize with your online Mesh account. So you always have a copy of your data floating around somewhere on the cloud.

There is more to it than this, but this is the gist of it. The goal of this article is to demonstrate just how easy it is to use the Live Framework to program against the Live Mesh service. With a small amount of code you’ll be able to create folders and store files in your Mesh account.

Data Access Objects with the Entity Framework

Introduction

For this article / tutorial I will demonstrate a quick and easy way on how to use data access objects (DAO’s) with the Entity Framework.

These data access objects form a layer between the business logic and the database access technology. The idea is that the business logic should remain ignorant of the technology used to access the database. Using this “DAO pattern” you can more easily interchange this backing technology.

In the text to come this will be demonstrated by setting up a simple domain model which will be modelled using the Entity Framework. Next a layer of DAO’s will be created on top of this domain model.

The business logic will only use these DAO’s to request or send back data from or to the underlying data store. How these CRUD operations are handled is entirely up to the implementation of the DAO’s and should be of no concert to the business logic.

By decoupling the business objects from the backing data store you can more easily switch to another database access technology such as for say Linq To Sql.

Entity Framework ObjectContext

Introduction

It’s been a good two months since the last post. Today I finally found some spare time to write a new article about .NET. This will be the first article on this blog focusing solely on the Entity Framework. More in particular about using the Entity Framework in different environments such as Windows Applications and in an ASP.NET environment.

The Entity Framework has some drawbacks that will hopefully be addressed in the second release, but in its current state it’s already a really useful technology to use for database access.

This article will not discuss every feature of the Entity Framework as that would entail writing an entire book. The primary focus is on how to deal with the ObjectContext in different environments such as a regular Windows Application and a Web Application (ASP.NET). Let’s get started…

MVP: Model View Presenter

Introduction

Last week I was reading some articles about using WCF, the Entity Framework and how to transport entities across the service boundary. One of the articles I encountered included a demo project that made use of the Model View Presenter (MVP) pattern.

Having explored the demo project I thought it might be interesting to write an article about this pattern. Your favorite search engine will happily supply you with a plethora of links to other articles that explain this pattern thoroughly.

For this article I’ve decided to supply a concrete implemention and to focus less on the theory behind the pattern.

Let’s roll…

ASP.NET Menu: Sliding Doors of CSS

Introduction

The purpose of this article is to create a slick looking and easy to use menu for an ASP.NET enabled website. In order to accomplish this we’ll use the standard functionality of the ASP.NET Menu web control and enhance the look purely by using Cascading Style Sheets (CSS).

For those of you familiar with CSS the title of this article will surely ring a bell. The CSS used to enhance the look and feel of the ASP.NET Menu control is decribed in a widely known article on A List Apart, entitled “Sliding Doors of CSS“.

The CSS used to improve the look and feel of the menu is thoroughly explained in the article on A List Apart. Credit when credit is due. Thank Douglas Bowman for supplying us with the CSS. Be sure to read his article first if you are not familiar with it.

The focus of this article is on how to simulate such a menu in an ASP.NET environment. Let’s get started…