Execution Time Based Heuristic Custom Task Scheduler

If you follow the samples for Parallel Programming with the .Net Framework, you may have come across the ParallelExtensionsExtras and the Additional TaskSchedulers. Although these samples cover a broad set of requirements I recently came across another that could be satisfied with the creation of a new custom task scheduler. In the current samples there…


Workflow Foundation (WF 4.5) – Designer Improvements

.NET 4.5 has introduced some great new features to improve the usability of the Workflow designer. If you’re rehosting the designer outside of Visual Studio then you can take advantage of most of these features very easily which is what I have done with Workflow Studio. If you’ve read my previous post you’ll know that…


Azure Access Control Services: Creating a Custom Identity Provider

Azure Access Control Services (ACS) allows you to secure an application (i.e. Relying Party, RP), by federating to a variety of Identity Providers (IdPs). Once you set your Relying Party application to use federated security with Azure ACS, you can chose combinations of Facebook, Windows Live ID, Google and Yahoo to secure your application. You can…


SAML 2.0 tokens and WIF – bridging the divide

Background We all know the following limitations about Windows Identity Foundation (WIF) and passive (browser) federation protocols, right? WIF does not support SAML2.0 protocol (SAML2P) There is a WIF extension out there to support SAML2P but it is a technology preview WIF does support SAML2.0 (SAML2) tokens WS-Federation conveys SAML1.1 tokens Therefore, unless you use…


Dealing with an XSD Choice when XSD.exe doesn’t add XmlChoiceIdentifierAttribute

On my current project we are dealing with some quite complex xsd schemas. Whilst working with one of these I was confused by what I was seeing in the generated code produced by xsd.exe; specifically where an xs:choice was involved. I was expecting to see: An XmlChoiceIdentifier attribute appear on the object in question An…


Access to an ASP.NET website via multiple authentications

Background Is it possible to secure a website using Windows Identity Foundation (WIF) without interfering with an existing authentication method? e.g. – Could a website secured using an ASP.NET membership provider, with all the code and configuration that entails, be layered with additional code and configuration to allow a precursory authentication with a trusted Identity…


Co-occurrence Approach to an Item Based Recommender

For a while I thought I would tackle the problem of creating an item-based recommender. Firstly I will start with a local variant before moving onto a MapReduce version. The current version of the code can be found at: http://code.msdn.microsoft.com/Co-occurrence-Approach-to-57027db7 The approach taken for the item-based recommender will be to define a co-occurrence matrix based…


.Net Implementation of a Priority Queue (aka Heap)

I thought I would take a break for a while from Hadoop and put together an F# .Net implementation of a Priority Queue; implemented using a heap data structure. Conceptually we can think of a heap as a balanced binary tree. The tree will have a root, and each node can have up to two…


ADFS 2.0: Single sign-on when a website references remote images

I recently had an issue where a website, secured with Active Directory Federation Services 2.0 (ADFS), was referencing images stored in another website, secured by the same instance of ADFS. This meant that if a user logged into the main website without going first to the website hosting the images, they would not see the…


Generic based Framework for .Net Hadoop MapReduce Job Submission

Over the past month I have been working on a framework to allow composition and submission of MapReduce jobs using .Net. I have put together two previous blog posts on this, so rather than put together a third on the latest change I thought I would create a final composite post. To understand why lets…