Serving medium size and large enterprises nationwide by building and customizing resources planning, consulting, customer management solutions. Research, design, development and support of bussiness information systems.

Tag Archives: C#

WIF SSO and Forms Authentication in ASP.NET

December 8, 2014 4:43 pm

One of the projects on which we are working is a long-lived ASP.NET Web Forms system that is customized for a specific client. It is hosted by another company on a server which is external to the client’s environment and it does not have an access to the client’s internal network. The system is built by using the Form Authentication mechanism to authenticate and authorize the users. The list of users and their hashed passwords is stored into the database and the login functionality works in a classic manner – the credentials provided by the user on the login page are validated against the list of users in the database. If the provided credentials are valid then a new Forms Authentication session is established by calling the standard method FormsAuthentication.SetAuthCookie().

Recently, we had to extend that authentication mechanism by adding a single sign-on (SSO) capability which allows the client to integrate the ASP.NET web application with their internal Active Directory (AD) infrastructure. The requirement was to allow some internal employees to access the ASP.NET web application through SSO, but also keep the exiting database login functionality for the rest of the users who are external and they do not have internal AD accounts.

The ASP.NET web application is hosted on an external server and it does not have a direct access to the secured AD infrastructure. After doing some research, we found that in order to connect the external ASP.NET web application to the internal AD environment we can use a middle service called Security Token Service (STS).


HTML 5 – The Offline Challenge

December 19, 2013 3:54 pm

HTML 5 – The Offline Challenge

I. Introduction

Some time ago our team had to add a new feature to one of our web projects. There was a request to add a capability to allow the users to use the application in “offline” mode. It was a great opportunity to dive into HTML 5 and more specifically the “offline” part of it. The new features of HTML5 are pretty interesting, but also “tricky” and this is why I would like to share some of the challenges we met.

First, I would like to say a few words about the technology on which the project is build. That is ASP.NET application which is storing data in SQL Server database. This is not a public application and only authorized users can access it. The system allows the users to go through their business process by entering the information in some structured web forms and at the end it allows them to generate a Word document, which is their final product. The web application is completely client-orientated and there is a huge usage of jQuery and AJAX. The AJAX calls are handled by WCF services. Frankly, this architecture made the implementation of the “offline mode” pretty straightforward.

Sending Email Messages with Embedded Images

December 19, 2013 12:32 pm

Sending Email Messages with Embedded Images

Usually, when we implement email notification from various applications we send emails containing HTML body. And when there should be an image within the email body we put the image on a web server and use a reference to that image in the HTML code. Following as an example of this:

Hello world

 <img alt="sample image" src="http://webserveraddress/Images/sample_image.png" />

The drawback with this scenario is the need for connection to the web server when reading the email. This is causing issues, for example, when the server is part of an intranet network that is not always accessible by the clients. More