But it works on my PC!

At the Software Craftsmanship 2010 conference I met Gael Fraiteur of Sharpcrafters, he had given a talk on Aspect Oriented Programming AOP.Since the conference I have had a chance to look at his Postsharp AOP product for .NET.

I decided to do a quick spike project for a tender I have been working on, the requirement is to add a security model to an existing .NET assembly. Usually this would have entailed adding some security logic at the start of each public method to implement the security model. Using AOP I hoped I would be able to get the same effect by adding an attribute to the classes/methods, hopefully making the changes easier to read and quicker to develop.

So I have the following business logic I wish to added security too. All I did was add the [Security] attribute to the business logic method

public class BusinessLogic

{

    IDataProvider data;

    public BusinessLogic(IDataProvider data)

    {

        this.data = data;

    }

    [Security]

    public DataRecord GetItem(int customerId)

    {

        Debug.WriteLine("BusinessLogic.GetItem");

        return this.data.GetItemFromDB(customerId);

    }

}

So what is in the AOP attribute? Basically I use the AOP framework to intercept the method call, and before the method is invoked I make a call to a factory method to get an instance of the security provider and check if I have the rights to run the method.

[Serializable]

 public class SecurityAttribute :MethodInterceptionAspect

 {

     public override void OnInvoke(MethodInterceptionArgs args)

     {

         Debug.WriteLine("SecurityAttribute.OnInvoke");

         // this assumes we know the type of arguement and that we can 

         if (MembershipProviderFactory.GetProvider().CanCurrentUserViewThisItem((int)args.Arguments[0]) == true)

         {

             Debug.WriteLine("SecurityAttribute.OnInvoke: We have rights to view");

             base.OnInvoke(args);

         }

         else

         {

             Debug.WriteLine("SecurityAttribute.OnInvoke: We dont have rights to view");

         }

     }

 }

As it was a spike project I did not bother to write the security provider (or the DB provider for that matter). I used Typemock Isolator to fake it all, so my tests were as shown below. I found this way of working much quicker for my purposes.

/// <summary>

  /// test for both the success and failure paths of the attribute

  /// </summary>

  [TestClass]

  public class Tests

  {

      [Isolated]

      [TestMethod]

      public void When_the_membership_provider_gives_access_the_data_is_returned()

      {

          // arrange

          // create a fake objects

          var fakeIMembershipProvider = Isolate.Fake.Instance<IMembershipProvider>();

          var fakeISqlProvider = Isolate.Fake.Instance<ISqlProvider>();

          // create real objects

          var fakeData = new DataRecord();

          var bl = new BusinessLogic(fakeISqlProvider);

          // Set that when we call the factory method we get the fake membership system

          Isolate.WhenCalled(() => MembershipProviderFactory.GetProvider()).WillReturn(fakeIMembershipProvider);

                      // Set when we call the DB layer we get the fake object

          Isolate.WhenCalled(() => fakeISqlProvider.GetItemFromDB(0)).WillReturn(fakeData);

          // Set that we are allowed to see the item

          Isolate.WhenCalled(() => fakeIMembershipProvider.CanCurrentUserViewThisItem(0)).WillReturn(true);

          // act

          var actual = bl.GetItem(1);

          // assert

          Assert.AreEqual(fakeData, actual);

          Isolate.Verify.WasCalledWithExactArguments(() => fakeISqlProvider.GetItemFromDB(1));

      }

      [Isolated]

      [TestMethod]

      public void When_the_membership_provider_does_not_give_access_the_data_is_returned()

      {

          // arrange

          // create a fake objects

          var fakeIMembershipProvider = Isolate.Fake.Instance<IMembershipProvider>();

          var fakeISqlProvider = Isolate.Fake.Instance<ISqlProvider>();

          // create real objects

          var fakeData = new DataRecord();

          var bl = new BusinessLogic(fakeISqlProvider);

          // Set that when we call the factory method we get the fake membership system

          Isolate.WhenCalled(() => MembershipProviderFactory.GetProvider()).WillReturn(fakeIMembershipProvider);

          // Set when we call the DB layer we get the fake object

          Isolate.WhenCalled(() => fakeISqlProvider.GetItemFromDB(0)).WillReturn(fakeData);

          // Set that we are not allowed to see the item

          Isolate.WhenCalled(() => fakeIMembershipProvider.CanCurrentUserViewThisItem(0)).WillReturn(false);

          // act

          var actual = bl.GetItem(1);

          // assert

          Assert.AreEqual(null, actual);

          Isolate.Verify.WasNotCalled(() => fakeISqlProvider.GetItemFromDB(1));

      }

  }

This all work beautifully and I have to say this was nice and straight forward to code. The code looks clean and using Reflector the generated code is OK tool.

My only worries are

1. That of performance, but after looking at the code I can’t see that the AOP framework generated code is any great deal less efficient that me adding security methods calls in all the business method. Using Postsharp would certainly require much less repetitive coding. In my spike the security factory strikes me as the bottleneck, but this is my problem, not the frameworks, and can be addressed with a better design pattern to make sure it is not created on every method call.
2. I can see complexity appearing depending on handling the parameters being passed between the attribute and method being invoked. In my spike I need to know order of the parameters so I could pass the correct one to my security methods, however again I don’t see this as being a major stumbling block, the framework could provide something I am unaware of or I just need to write few forms of the security aspect constructor.

So will I be using Postsharp? I suppose immediately it depends if I win this tender, but I have to say I like what I saw from this first usage.

I have always read a lot of novels, and I like to have a book with me for those unexpected moments when I get a chance to read. Of late this has meant I use the Microsoft Reader on my phone. It is not too bad an experience, using Project Gutenberg I can get a book (fiddle a bit in Word) and export to the Reader format. However I would like a slicker experience and be able to read new releases, so the Kindle seems just the job.

As a device it seems perfect, about the size and weight of a paperback, excellent battery life (as power is only used to turn/display the page, not to view pages), excellent in natural light and now the price has dropped to the point that if you did lose it you are pissed off, but not bankrupt. Oh and dropping in the bath, though it might ruin the device will not electrocute you!

My problem is the price of new books, take William Gibson’s Zero History as an example. On Amazon this is £12.29 in hardback but £9.99 for the Kindle edition. So from this we assume the production costs, shipping warehousing etc for the physical copy total £2.30, seems a bit low to me! How is the £9.99 justified, there will be the writer’s royalty, the file production costs and the marketing and other publishing overheads but £9.99 seems steep, especially give the royalty rate that I know friends who are writers gets for their novels. Someone is making a tidy profit, and it is not the writer.

If we look at one of Gibson’s older books, Spook Country, now in Paperpack for £2.99 we see the Kindle price is £2.84. So it seems the Kindle price is set at (very roughly) 10% below the lowest physical edition cost.

So I am being asked to buy a eBook at almost the same cost as I can get a paper copy, when the publisher/supplier chain do not have to make the physical copy or ship it. I get the convenience that I can carry around 3500 books at a time, but I can only read one! Also I cannot lend a book to a friend, thus I admit reducing the potential royalties of a writer, but also removing any viral marketing opportunities.

So should I buy a Kindle? At this price for the eBooks I think not. I will stick to buying my new books on paper and keep a selection of out of copyright classics on my phone. I will wait until the publishing industry reviews it sales model for these editions, maybe increasing the writers royalties to reflect that it is their efforts that are being purchased not examples of the book binders art!.

I had a strangely thought provoking weekend, I took my son to do the tour of Concorde at Manchester Airport, and whilst in the area popped into Jodrell Bank to look at the Radio Telescope and the arboretum. Two great technological achievement, well worth a visit, but I felt both seemed to be in our past. I remember Concorde, I remember Apollo (just) and I remember sitting in a room at school to watch the first Shuttle launch, but where is the equivalent today? I started to feel that this ‘thrusting to the future’ style of project no longer exists; there seem to be few children saying ‘I want to be an engineer’ or ‘an astronaut’. I fear they are too often now saying ‘I just want to be famous’.

But then I thought a bit more and I think these projects are still there; we have had the LHC switched on last year and just last week BBC News covered the break through of the Gotthard Rail Tunnel. Big science/technology is still a news story, but I have to say more usually not in the positive sense, too many stories are presented in the ‘science gone mad’ category. We (or should I have said the media) have lost the awe for big science and replaced it with fear or at least a mistrust.

Maybe I am just looking at the past with rose tinted spectacles, Jodrell Bank was over budget about 10x and people complained ‘why send men to the moon when people are starving on earth’, so maybe the coverage was the same. The current mainstream tone of reporting could just be a factor of living in a less deferential age. For me there is no question it is good to question the value of science, but this has to be done from an informed position, you have to least start to understand the question to give an reasonable opinion (or even ask a reasonable question in the first place).

What I worry is that this move, this lack of awe and excitement in science, will drive children away from wanted to be involved in science and technology. At least we are seeing a return to accessible science on the BBC (worth every penny of the license fee) in Bang Goes the Theory, the World of Invention and the new archive of The Great Egg Race (proper 1970’s mad scientists, I doubt you would get a 30 minute programme today with people fiddling with bits of string and rubber bands whist wearing wing collar nylon shirts, think of the health and safety static risk alone!).

So I guess my initial fear is unfounded, there is the sense of wonder out there, maybe we just have to make more of an effort go to find it.

Recently Packt Publishing sent me a copy of ‘Refactoring with Microsoft Visual Studio 2010’ by Peter Ritchie, I have to say I have rather impressed by it.

My only major issue with it is that of the title, this book covers much more than the refactoring features of 2010. It provides a very clear example driven discussion of the use and application of both refactoring patterns and design patterns. I think this would be an excellent book for a developer who want to start to apply design patterns to their C# code. The examples being more real world than Head First’s ‘Design Patterns’ (and the examples are in C# as opposed to Java) and the book being a far easier read than the classic ‘Design patterns : elements of reusable object-oriented software’

It is telling how much the book contents differs from the title that one of the most common sentences seems to be ‘that this is a not a build in automated refactoring in Visual Studio 2010’. Even though this appears fairly regularly the author goes onto explain how this limitation can be addressed in nice practical ways, interesting choosing to not mention third party refactoring tools until virtual the last page of the book.

Basically this book discuses theory in a nice accessible manner. It is not a simple ‘click here to do this’ tooling reference, don’t let the title fool you. It is well worth the read, you can see a sample 'Chapter No 6 "Improving Class Quality' online at Packt

I am very impressed with the iPlayer Media Center Plugin I found on the Australian Media Center Community, I like most people found it installed fine but that it failed to add itself to the start menu. However this was easily fixed using Media Center Studio once I got my head around the Media Center Studio’s user interface. The basic process is:

1. Load Media Center Studio
2. Go onto the Start Menu tab
3. At the bottom of the screen look for the entry points section (needs expanding usually)
4. In here you should find the iPlayer application (has a red’ish pay button logo)
5. Drag it onto whichever part of the start menu you want, but be aware there are some limitation as to where it can go, Extensions worked fine for me
6. Save the changes
7. Restart Media Center

Once this is done you should be able to view WMV based iPlayer content from within Media Center. I have seen it take a while to start buffering content, but other than that it seems to work well and certainly looks the part.

In the VSLive! keynote Microsoft made announcements about Lab Management, it will be RTM’d later this month and best of all it will be included as part of the benefits of the Visual Studio 2010 Ultimate with MSDN and Visual Studio Test Professional 2010 with MSDN SKUs. You can read more detail on Brian Keller’s blog

I think this is a great move on licensing, we had expect it to be purchasable addition to Visual Studio. With this change it now is consistent with TFS i.e. if you have the right SKU of Visual Studio and MSDN you get the feature. This greatly removes the barrier to entry for this technology.

I look forward to have a forthright discussion with our IT manager over Hyper-V cluster resources in the near future

I have been meaning to watch back the video taken of my recent presentation for a while. This weekend I have had the chance to sample the highlights! In the past I have always found it hard to watch myself on recordings, though after the initial cringe this time it was not too bad. I must be getting used to the critical process.

So what have I learnt

• I say ‘err’ to ‘err’ much ‘err’
• I move my hands about much like Magnus Pike, a childhood 1970/80s TV popular science reference as seen in this Thomas Dolby video and this Mitchell and Web sketch, for those not old enough to remember. I don’t think it is too irritating do you? But to carry it off fully I do need madder hair.
• I tend to wander about the stage, I know it is consider good presenting practice not to talk and walk at the same time. But does this actually get on the audiences nerves? It certainly does me when watching when I jump up and down during a demo. I think I know why I am doing it, I heard about an idea from NLP for presenting/teaching to always deliver specific types of information from the same physical location e.g. funny anecdote by the windows, summary points by the lectern etc. The idea is it subconsciously primes the audience what to expect and how to treat it e.g. oh here he is by the lectern I must remember this as it is important. I guess I need to just be a bit more sparing in the application of this technique.
• I still use too many slides, I especially need to focus on less bullet pointed ones. When presenting at the BCS recently the projector broke 5 minutes into my session and I did the rest of the session without slides (that the audience could see). All I missed was a couple of images of Scrum and Kanban (and wild hand waving an pointing at a white wall got me round the problems). I the feedback I got was good. However a key factor was I could see my bullet pointed slides on my laptop. I realised the slides are my speaker notes. So next time I intend to try very few audience slides but have a stack much like my normal one running on PowerPoint on my phone. Lets see how that works.
• …..Oh and I have a Birmingham accent, someone could have mentioned it!

I would heartily recommend anyone presenting to have a look at videos of your sessions, even if they are just ones taken with a camcorder or phone from the back of the room. You may be surprised how you appear, sessions often look very different to the audience as opposed to how you felt it went from the stage.

If you want to checkout my performances just search for ‘Fennell’ on conference media sites:

• Microsoft UK Techdays 2010 - http://www.microsoft.com/uk/techdays/resources.aspx a session on Lab Manager
• Norwegian Developers Conference 2010 - http://streaming.ndc2010.no/tcs/ three sessions, one on Lab Manager (the Techdays one is better), one on Manual Testing with VS2010 and finally one on Testing Sharepoint Webparts with Typemock

Enjoy……

The BCS has had its EGM today and the results are out. Basically the vote is about 75% in support of the status quo, which I am not surprised by. What I am really pleased to see is that the Trustees withdrew the special resolution the change the number of people to required to call an EGM from 50 people to 2% of the membership.

I really do hope that this whole EGM process has been a warning to the Trustee and board that they must be more open, and help promote and continue the dialog that EGM has created.

Gil at Typemock has been posting about some ideas we discussed over breakfast at the Typemock Partner conference a while ago, I have been a bit slow at commenting, so I though I better add to the conversation. Though Typemock is an excellent mocking framework, for me basic mocking is not its biggest win. All the ‘classic auto mocking’ of interfaces to speed TDD style working is great, but I can do that with any of the .NET mocking frameworks. All they do is mean I don’t have to write my own test stubs and mocks, so saving me time, which is good but not the keep win I was looking for.

For me there is another way to save much more time and that is to reduce my ‘build, deploy, use’ cycle. In the land of SharePoint this is a significant time saving, or at least has been for us. It has meant that I can replace the build, create WSP, deploy WSP, let SharePoint/IIS restart and then view a web part, with a build and view in ASP.NET page that uses Typemock to fake out all to SharePoint calls. This is what Gil has termed Isolation Driven Development (IDD) Now isn’t a three letter _DD name going a bit far, I am even not sure there enough in it for me to write a book!

That said this is a solid technique which can be applied to any complex environment where developers or testers need a means to mock out significant, costly, or just slow components to ease there daily work process, often enabling some manual testing process, thus making them more productive. If you read the TPS books it mentions a lot how workers should optimise their work space to reduce wasted time the spend moving between machines or roles, this is just such a move.

So if you want to use the technique for Sharepoint have a look at my post, I hope it will save you time whether on SP2007 or 2010, or maybe apply same technique to other technologies.

What a great event the Norwegian Developers conference is. It is a nice size so there is a good selection of tracks, but no so big you feel lost, also the speakers and attendees were all mixing freely which I think always makes for a good atmosphere. This was all enhanced by the excellent organisation of the event, what can I say the wifi worked faultlessly, the food was good and the overflow screens (so from one place you could view the video and audio of any current sessions) was a brilliant idea, so much I know some people took to using this in preference to going to the actual session. You can see the overflow screens at the top of the photo below.

On the subject of food it was good to have a breakfast, a ‘lunch bite’ and then another small meal around 4pm just when you are flagging. It was noticeable that the sponsors on the expo had basically got rid of all the swag and replaced it with a selection of snacks and coffee machines. For me far more acceptable to get a nice ice cream or a hot dog rather than yet another USB pen drive or fluffy toy with a corporate logo on it. I even enjoyed the band at the ‘legendary NDC party’, the organisers seemed to get all points right.

Also what was nice was that this was not a single vendor conference e.g. a TechEd or PDC. Now these can (but not always) be great for new product knowledge, but they can constrain the subject matter. At NDC there has been a good wide range of subjects with a particular strong Agile process and Ruby tracks. I for one would want to go to conferences to be exposed to things I have not used before, both technologies and concepts. This I feel you can for better at a conference with a wider scope of subject matter than a vendor conference. Now the danger is that the range becomes too wide and dilutes the content, but at NDC again I think they got it about right

Remember all the sessions at NDC were videoed in HD, and they are being rapidly being uploaded to http://streaming.ndc2010.no/tcs/, so if you are interested in seeing my or any other sessions from this ‘amazing line-up!’ take a look.

I hope any sessions I submit for NDC2011 in May next year get accepted, I would love to go back.