OpenRasta status update

This entry may be outdated. For the latest updates on openrasta, see www.openrasta.com.

A couple of people have access to the code and have been kind enough to give reviews. I’m always open to more people helping out in the very early design phase before I go all public with the framework I’ve been nagging everybody about for months and months, so pop me an email to seb@serialseb.com and I’ll give you access. OpenRasta will be under an MIT license and I’ll publish it all to the world. I need to ensure what needs refactoring before release is refactored and that it is a fully functional beta first.

So here is what can be done with OpenRasta now and what I’m currently working on. See it as both an announcement and my task-list to the runner-up to the official release. You can refer back to the previous version of OpenRasta I already introduced. For various reasons the original Rasta never made it to open-source and its code has now died, and as far as I know no one will maintain it. OpenRasta is a fresh take on it, but keeps the same configuration API and the same concepts in a fresh new format with fresh new codes (and fresh juicy unit tests).

So by now you know there are essential components in OpenRasta: URIs, Resources, Handlers, Codecs and the pipeline.

The framework

• OpenRasta.dll contains the bulk of the implementation, and compiles successfully on the .net framework 2.0 and on Silverlight. Great for embedding OpenRasta in your traditional asp.net application and start migrating your code over. And why not provide a REST-friendly server from the .net Compact Framework? (starting to sound like a marketing drone there)
• The silverlight support will eventually provide for duplex http so you can architect your RAI test-first and REST-friendly, reduce coupling, and enjoy your life more. IN PROGRESS.
• Most of the features are implemented straight into OpenRasta, such as dealing with form content-types browser send you. That means no reliance on some of the asp.net limitations on file uploads.
• OpenRasta.Server.dll is your asp.net integration point, with support for traditional IIS6 and Integrated IIS7 modes.
• Did I mention OpenRasta runs on asp.net 2.0? Alongside your webforms?

The pipeline

• The pipeline is a series of pipeline contributors. They all act upon a small area of functionality, change a couple of things and give control back. The good news is that you have full power to change any of the existing contributors, add your own, etc. The default pipeline has 17 components which support the execution of the whole system.
• Each contributor registers when it wants to be executed, and it is always relative to another contributor. The pipeline, once initialized, builds a chain of calls and execute them sequentially. And there is a small type that will let you register for multiple steps in the pipeline and be called only when you are ready.
• You can add and remove contributors at configuration time to replace or modify existing behavior. IN PROGRESS.

URIs and URI decorators

• You define your resource Uris using the common http template syntax. It’s a clean-room implementation of the .net 3.0 UriTemplate and UriTemplateTable classes to run on 2.0. It will support both the 3.5 modifications and some extra features sometime in the future. May donate the code to mono if their implementation hasn’t progressed much.
• Several Uris can identify the same resource, but in different languages. /home and /accueil will automatically set-up everything you need to override the default client’s language.
• Of course, in any real-world scenarios, your URI doesn’t only describe an abstract resource that is easy to name. There are plenty of little tidbits of things you may want to include, such as the document type (.html anyone?), the language (/en/mydocument), maybe even the version (/en/mydocument(v1)). Most frameworks would have you declare all the combinations of those urls to design your resources. In OpenRasta you simply define a Uri decorator that will change the way the request is processed and clean-up the Uri before passing it on for processing. Out of the box, you’ll have document types, language, http method overrides (for those nasty PUT you want to do from your html forms) and view selection (for when one resource have several views applied to it).

Handlers

• Once your Uri is matched to a resource, a handler is going to be selected and one of its methods called.
• You don’t have to inherit from anything, or implement any interface.
• You name your method using the name of the http method the client sent you. Want to send data? Implement a Get(). Want to append data? Implement a Post().
• Sometimes you want more meaningful names. Just declare a small attribute to map the correct http method to the correct clr method.
• Parameters are declared naturally, without multitudes of hacks, strings or attributes. The codec will be responsible for mapping whatever the client sent to whatever CLR types you are expecting. The framework will map your url templates to your parameters too.
• Want optional parameters? Add an [Optional] attribute. Want a default value? Enter [DefaultValue]. And any CLR language implementing default values will support those too. I think that includes the VB guys :)
• You can even have parameters that map to http headers.
• Your handler method returns what makes sense to you. Don’t want to return any resource to your client? Discover the joy of the void return type! Always return a type? Just declare that type as the return type. And when you want to return RESTful information, simply return an OperationResult.
• Your handler only select objects, not views or other things that doesn’t concern it. You return an object and a Codec will render it to the client.
• And of course, you can add plenty of filters that execute before and after the method calls. A logging filter (IN PROGRESS) and a Principal security filter come out of the box, so you can get people to authenticate.

Codecs

• A resource can be read and written from and to an http connection using Codecs. Some are provided in Rasta (json, xml, html, html form data), and writing one is brain-dead easy.
• You can let the client decide which content-type it will receive by using well-established content-type negotiation semantics. It’s all done for you. And it even serves application/xhtml+xml to firefox without you having to touch a line of code.
• When sending data from html forms, <input name=”customerName” value=”value” /> will call Post(string customerName);
• Ok, everybody does that. When using <input name=”Customer.Name” value=”value” /> this will call Post(Customer customer) with the correct property done for you.
• Ok, most MVC frameworks do that. When using <input name=”AddressOf(Customer).PostCode” value=”value” /> this will call Post(AddressOf<Customer> customer) with the postcode property set.
• Ok, some MVC frameworks do that. When using immutable types, <input name=”Customer.DateOfBirth.Date” value=”12” /> the method Post(Customer c) will be called with the date set on a new date of birth. And you can set property chains as far as you want, and write to read-only properties. Convinced yet?
• Ok, maybe some MVC frameworks may be able to do that. When using <input name=”Customer.DateOfBirth.Date” value=”12” /> the method Post(ChangeSet<Customer> c); will be called, and you can update your objects with whatever changes are being sent through.
• Oh, and the same stuff can work with other content-types too. Implementing http patch has never been that easy.
• Codecs also can use different views. Want to have one page to view and one page to edit your customers? Just declare a view using TranscodedBy<WebFormsCodec>(new { index = “~/CustomerView.aspx”, edit = “~/CustomerEdit.aspx” });
• The return data depends on what the client requested. And that includes error pages, 404s, 401s, etc. IN PROGRESS.
• You can stream data from the client rather than have asp.net download everything for you, for any multipart type. IN PROGRESS.

And the rest

• Http Digest Authentication out of the box. IMPLEMENTED. With time-sliding security window and logoff functionality! IN PROGRESS
• An error mechanism for your webforms to manage validation errors while still returning RESTful status codes, that still renders correctly when dealing with json, xml, etc. IN PROGRESS.
• Everything, and I do mean everything, goes through an IoC container. If you don’t use one, OpenRasta use its internal one. If you use one, OpenRasta automatically registers all its dependencies in it. Comes with a Windsor Castle implementation.
• All the configuration can be done without a single attribute anywhere, either by leveraging conventions or using the fluent configuration API.
• Automatic cache management based on your resources (including Last-Modified and ETags). IN PROGRESS.

What to look forward to in beta 2

• VB9 XML literals, NHAML and NVelocity view engines. NOT STARTED.
• Full AtomPub support. NOT STARTED.
• StructureMap support. NOT STARTED.
• An additional configuration mode for the attribute junkies that will scan your assemblies and configure OpenRasta automatically. NOT STARTED.
• Support for asynchronous operations (need to define the exact use-cases for this first). NOT STARTED.
• An optional reverse cache for your handlers. NOT STARTED.

Way past my bed-time. That should give you a good idea of where I am at with OpenRasta and what kind of things it will enable you to do. Email me to peek at the code before anyone else!

Porting the Suteki Shop to OpenRasta

Mike Hadlow has just announced the commercial release of Jump the Gun, an online shop based on his Suteki Shop cms. Mike is an extremely bright guy that I’ve met quite a few times at various conferences, and he’s built it all on asp.net MVC.

Because OpenRasta doesn’t have much of a documentation at the moment, and because it would be nice to have a comparison between the two systems, I’ve offered Mike to start porting Suteki to OpenRasta sometime over the weekend. The good news is that it will live side-by-side with the existing Suteki Shop. I’m leaning towards calling it Sutekool :) . And then we’ll be able to compare the performance and flexibility of both frameworks. I’ll porbably learn a lot in the process,

Thanks Mike for the great work and for the opportunity of having the first side-by-side comparison of asp.net MVC and OpenRasta! Now if we had someone porting it to monorail, we could have a real overview of what the .net MVC world has to offer.

Building a new server at RapidSwitch

I’ve been on the lookout for a windows server 2008 server for quite a while, and have now selected one. The thing that surprised me in my search has been the complete lack of professionalism exhibited by some hosts on their websites.

• If you don’t tell me where your datacenters are, you probably don’t have datacenters and are just reselling.
• If you don’t provide your company details on every single of your pages (hint: uk limited companies *must* provide their company number, vat registration number, registered office and full name, including “limited” or “ltd”. copyright midnight software is *not* enough), I don’t know who you are and for all I know you don’t actually have a company.
• If you don’t provide an SLA, I do not trust you will apply it.

So with all those, 90% of the hosts I found selling Server 2008 hosting were out. RapidSwitch seems to have had good reviews, so I just created an account, and have had two tickets in the last few hours telling me my server was now racked and the OS is installing, from a gent called Kyle. Although I am pretty sure Kyle is a bot, it’s still very nice to know what is going on.

I’m going to keep this post open to give my feedback on their service as I use them. They are confident enough in their service to not tie you to a 12-month contract. Depending on how things go in the next couple of weeks, they'll probably sign me for 12 months or loose me. Kudos for leaving the customer in control.

Roll Server 2008!

The content of the presentation at VBUG Brighton tonight

As last time I got completely overloaded with work and forgot to post the content of the demo, this time I’m doing it the other way around. Code is available on my public mug (get it? caffeine-it, mug, public? Funny? No? Oh well). Point your favourite svn tool to

http://svn.caffeine-it.com/mug/bingo

From the command line

C:\> svn co http://svn.caffeine-it.com/mug/bingo bingo

Will add the updates I’ll tweak till then and the powerpoint slide sometimes tomorrow at the same place.

See you all tonight in Brighton, or over the next two days at Mix!

Alt.net London Beers #3 – 14th October 2008

Following on the success of the previous events,I am happy to announce the next alt.net London Beers event.

The format is going to be different from the previous event, as it will be a sort of mini openconf-style session. Here are the rules

• Arrivals, discussion and socializing between 18:00 and 19:00, with one necessity: find the topic of the day and find the questions that we will try to answer. We may provide post-its, white boards or body painting equipment to help people focus.
• At 19:00 the big clock will start ticking for a time-boxed 60 minutes workshop on the subject. The goal is simple: can we as a group get insight and progress our understanding of the problem. The specifics of the format will probably change when we get there, but I’d like us to focus on up to 4 questions.
• At 20:00 the clock will ring and that will be it of the conversation. Everyone will be invited to fill-in a wiki with a one or two line answer for each of those questions. The goal is to capture a snapshot of the state of mind at the event, and to be able to compare those with the result of our reflections that, I’m sure, will be extensively shared on blogs, mailing lists, twitter, etc.
• One this is all written down, everybody will be able to continue the discussion in the pub or wherever they see fit.

Please leave comments here and everywhere you feel relevant, or hit me on twitter, to suggest topic ideas or to provide criticism of the whole concept. Without feedback one cannot separate success from failure, and recognizing those are necessary to progress and improve.

If your company wants to invest a bit of money behind the bar for food and drinks, don’t hesitate to let me know.

And of course, the location is the same as the previous event, and I have been told the kitchen staff will stay a bit longer for us this time.

The Blue Posts
18, Kingly Street
London W1B 5PX

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Technorati Tags: altdotnet,altnetuk,alt.net,altnetbeers

Developing .net code since 2000?

Over the years, I’ve had a couple of people in interviews being surprised at my assertion that I started development on .net in 2000. As I go through yet another cleanup of my email archives (I’m an archival freak) that are reaching around 15GB of data, I found this email.

From: DeveloperStoreAdministrator@developerstore.com [mailto:DeveloperStoreAdministrator@developerstore.com]
Sent: 14 November 2000 03:09
To: …
Subject: Thank you for your recent Microsoft purchase

Thank you for visiting our store, Sebastien P. Lambla.

Your order has been entered into our ordering system, and will be delivered to you soon. At that time, the charge of $15.99 will be charged to your credit card.

This is an unmonitored email alias. Please do not reply directly to this email alias as the messages will not be answered. If you have questions or would like to check on the status of your order, please email us at mstoolbox@interactservices.com.

Refer to order number MSDSTB129915 when contacting us.

Thank You,

Microsoft Developer Tools

This was the first beta of visual studio. 8 years of C#, how time flies!

Kaizenconf is open

For those that were waiting for the kaizenconf registration to be open, it now is. But it’s not really a registration, it’s a request for a registration. So if I understand that correctly, I still don’t know if I’ll be there or not.

If you come from good old Great Britain, I’d recommend booking anyway. With the sterling going down, cancellation fees will probably be cheaper than waiting and see your money be half what it was.

Work availability

If you’re looking for help with your project and need a consultant, I’m available for the first two weeks of October. And if you’re looking for a developer / lead developer, I’ll be available from mid-November!

So don’t hesitate to contact me at seb@serialseb.com and cut some of those agencies cost!

Vote now for DDD!

Quite many very interesting session proposed for the next DDD.

Go and vote now for your favorite sessions (and if you don’t like any, you can always vote for mine!)

The case of global.asax not being executed in IIS7

Global.asax is used in both asp.net MVC and OpenRasta for implementing your configuration. In Rasta 1.x, the handling of request was done through a catchall http handler. This has a couple of adverse effects for the application: all requests went through rasta first, and got delegated to IIS when there was no match. This can cause a range of performance issues, from lack of caching to constant file access when the delegation ends up using DefaultHandler rather than StaticHandler, as in those instances the files will systematically be streamed from the disk.

Another struggle I had with this system was the various issues encountered when trying to host the system on IIS7, something I started doing a while ago. I remembered reading from a blog that asp.net MVC was using both a handler and an http module, and investigated using a similar configuration for OpenRasta. As I do not want to be influenced by other people’s coding abilities, I have stayed away from reading the asp.net MVC source-code and tried to come up with my own scheme.

One particular issue comes from the different framework versions supported by OpenRasta: I run on plain old asp.net 2, and this means that all the new APIs that let you change a handler on the fly during a request will not work, as they are added by .net 3.5 sp1. Instead I came up with a clever trick: Just before the handler is resolved, I rewrite the url to a fake url, properly called ignoreme.rastahook. The extension rastahook is always associated with a compatibility handler that then gets called by the asp.net infrastructure, at which point I rewrite the url to what it was before the change, and execute my own http handler from there. The solution is not entirely perfect yet, as there is no support for asynchronous handlers, but as with every other part of OpenRasta I’ll be able to change that without impacting any handler already in existence.

As soon as I implemented those changes, everything went much more smoothly on IIS6 and cassini (the visual studio web server), but broke completely on IIS7 integrated mode on my local box. After much debugging, I realized that my global.asax wasn’t being called. When I added back an http handler to my web.config, the global.asax code was called again.

The reason is a bit confusing to understand at first. In IIS7 integrated mode, http modules are treated as being part of IIS, be it that they are managed or not. This means that a module may or may not rely on asp.net. Your module will be executed but your web app won’t necessarily have been compiled. Handlers on the other hand, when they are managed, trigger the asp.net application, and your code will get executed.

So to conclude this issue that i’ve been chasing for two months now: if you don’t have a managed http handler for your request, your http module will be called but the asp.net part of your site will not have been compiled and / or won’t be called, including global.asax. The solution is to ensure you have a managed handler in place, or force a compilation of the root site using BuildManager.GetReferencedAssemblies.

P.S.: this is all based on empirical evidence, so I may be absolutely wrong, and would be glad for anyone to come up with an alternative explanation.

Microsoft, for Christmas I’d like…

• A Visual Studio SP1 ++ that fixes all the bugs you’ve recently introduced
• A web designer that passes the ACID2 test
• A browser that implements the *freakin DOM*

I promise I won’t be a good boy, but then again, when I have to work with some of the tools you sell, I know who is to blame.

/me goes back to his office and wreck a few toys

The rubber duck in agile teams

Saw this from twitter and it made me smile: http://www.ademiller.com/blogs/tech/2008/08/scrum-bestiary-the-rubber-duck/

Have you had a rubber duck to deal with?

Proposing a syntax to attach behaviors to html elements

ScriptSharp, like asp.net AJAX, has the notion of behaviors, javascript code that can attach itself to DOM elements and change their, well, behavior.

As part of my spike on ScriptSharp (and I’ll have to admit having spent way too much time on it to still be called a spike), I’ve built a simple container that automatically resolves and binds behaviors to DOM elements, to reduce to a maximum the amount of inline code required within my generated pages.

The one thing I went round and round about was how to declare in markup that binding. Here’s a few solutions I tried or seen proposed through various tools.

<div style="behavior: url('myBehavior.htc')" />

This is something introduced in ie4, but it breaks the CSS standard *and* htc are only recognized by Internet Explorer. No good to me.

The next contender is…

<input type="text" id="searchText" /> <input type="button" id="searchButton" /> <script type="text/xml-script"> <page xmlns="http://schemas.microsoft.com/xml-script/2005"> <references> <add src="ScriptLibrary/Atlas/AtlasUI.js" /> <add src="ScriptLibrary/Atlas/AtlasControls.js" /> </references> <components> <textbox id="searchText" /> […]

…xml-script, and was originally presented early in the life of asp.net AJAX (back when it was called ATLAS). This is awfully verbose, and worse than that it won’t ever validate in non-xml languages (aha HTML 4.01 or XHTML5). The same is true of the proposed changes in asp.net AJAX Futures, which uses namespaces everywhere even though they’re not allowed in non xml renderings.

[Update: As Simon Pieters correctly points out in the comments, this syntax would indeed be compatible with HTML5 (the non-xml serialization one), because the definition of CDATA sections has been modified to include anything not including the closing tag. Hence what is after <script> can be anything that is not </script>. This redefined definition of a CDATA element is not something the XML specification agrees with however, which means that in all languages, aka XHTML 5.0, XHTML 1.1, XHTML 1.0 and HTML 4.01, you need to enclose the content of the script tag in a CDATA section, aka <![CDATA[ … ]]>. This makes HTML5 the only rendering with which xml-script would work. I may have misread some of those specs however, so if I have please comment and I’ll update and buy you a beer.]

In choosing how to map behaviors, I had several goals:

• declare the behaviors contextually within an element,
• being able to use the exact same notation for both HTML 4.01 (the SGML language), XHtml 1.0 and 1.1 (the XML language) and Html 5 (both the whatever it is format that is not sgml anymore *and* the xml language, as both exist)
• being able to pass additional customizations and parameters specific to an instance
• Not look too out of place.

I initially settled on an extension to the way content type definitions are expressed:

<div class="behavior/graphicscroll;horizontal=true;vertical=true;">test</div>

This says, ask the behavior family to add a graphicscroll behavior and pass it values for horizontal and vertical. All was good and I was happy with myself. For a whole five minutes.

Then you realize that while that syntax works like a charm, it is invalid in Xhtml 1.1, because the class attribute was redefined to be of type NMTOKENS, where the previous version had a type of CDATA. This is a serious breakage for content out there, and I wonder what the reason for this is.

The other issue I had with this is the need to declare the full syntax for each element I wanted to use, and I really wanted to leverage CSS selectors. One solution I would have wanted to use was to simply extend the CSS stylesheets with custom css attributes. This would have then looked like the following.

    <style type="text/css">

        div {

          -rasta: "behavior/graphicscroll;horizontal=true;vertical=true";

        }

    </style>

The syntax just felt very unnatural. And worse than that, the CSS validator doesn’t validate CSS with vendor expansions, even though they are defined as such in the specification.

After twiddling around endlessly, I’ve settled on defining a css-like language, behavior stylesheets, without some of the restrictions of the existing CSS. I now have this code:

    <style type="text/vnd.rasta.bss">

        div

        {

          behavior: graphicscroll {

              horizontal: true;

              vertical: true;

            }

        }

    </style>

The  selector syntax is simply the CSS one, which means you can combine and match them in the same way you would define your stylesheets. The properties however are dynamic, with the first level name always matching a family of components (implemented as a loader) with a value matching the component, and a sub-group letting you define properties on that component.

You’ll notice I mentioned my first goal was for this to be contextual within the element. Because you’re still using selectors, nothing prevents you from declaring a value in your class attribute and do your selection on that. The same of course goes for ids.

Time will tell if this is as compatible with current UAs as it could be, and I have the feeling it will be ignored when necessary, but it’s extensible, simple enough, doesn’t require the script engine, leverages an existing html element and still passes in all versions of html that support the style element.

When a provider ditch its own product…

I’m currently researching Server 2008 VPS products available, and stumbled upon bytehouse’s offering:

Why use a Windows operating system?

Windows Hosting is only really needed if you require ASP (Active Server Pages), Access Databases or VBScript.

Why use a Linux operating system?

If you just need to host HTML (Hypertext Markup Language) or PHP Web Pages, then Linux Hosting would be the better and cheaper choice for you. Linux has a proven track record of performance, stability and security within the Web Hosting industry.

Oh, god, I have Linux envy now, thanks!

Come and listen (or talk) about asp.net MVC in Brighton!

VBug apparently didn’t learn their lessons from the last presentations and asked me to come back to deliver my Bingo asp.net MVC talk in Brighton, the day before ReMix! You can have a look at the event, and frighteningly it is already fully booked!

You can expect a run-down of the MVC pattern, plenty of code (but less than last time), and of course Bingo.net in its third version. I may have some surprises in stock so be prepared for anything.

For anyone down in Brighton on that day, I’ll be staying there so expect a full attendance at the pub. The only true way to start any conference is with a hangover.

Using getElementsBySelector in ScriptSharp

I’m on my way to my second spike for one of my clients on playing with ScriptSharp to extend Rasta with Ajax functionality, and really wanted to be able to select elements as I would in CSS, using selectors (something I got quite used to with jQuery).

ScriptSharp comes with various assemblies you can link to. The one called sscorlib is a .net mapping over a javascript library that extends document to have a getElementsBySelector method. But for some reason, ScriptSharp doesn’t map that method.

So how do you call random code in ScriptSharp without resorting to evil eval code? You create a function of course! Here’s the snippet.

        public static DOMElement[] GetElementsBySelector(string selector, DOMElement root)

        {

            return new Function("return document.getElementsBySelector(selector, arg);", "selector", "arg")

                .Call(Document.DocumentElement, selector, root) as DOMElement[];

        }

We define a function that calls the correct javascript code, declare the argument names we will pass it, and finally call it by passing our selector and the root.

In one word, sweet.

Received this morning

Dear Sebastien

We are currently searching for a JOB TITLE to work in  CITY, COUNTRY  for DURATION plus extensions. This is a fantastic contract opportunity for a large multi-national client.

The ideal candidate must have the following skills: SHORT JOB DESCRIPTION.

A nice way to start the morning! Where do I sign?

“It doesn’t work”

Something seriously cracks me up. I hear day after day people telling me one technology or another, one tool or another, fails in matching their expectation, and explain the situation by it doesn’t work.

As soon as those words are muttered by someone in a team with low knowledge of the toolkit they are dealing with, you see developers running around to work around the symptom, replace the technology, or completely screw up an architecture or a design just to make it work.

Just the same, while TDD and fast feedback cycles have brought to the development community an antidote to the press F5, it works, I’m l33t, you still find a large number of rogue developers that still manage to write no test, go head down in development, produce unmaintainable code and still manage to lift it off because the UI is shiny and the managers don’t have a clue about the importance of quality and maintainability, as they don’t have the responsibility of their v2 budget.

Whenever faced with an intellectual challenge, you have two categories of people: those who step up, learn and understand a problem before finding a solution, and the it doesn’t work and Oh I press F5 I’m good! developers. My word of advice to the latter, if you are given guidance and mentoring and refuse to step up, you will eventually be out of work. Embrace change, challenge yourself and don’t discard mentoring when it’s given to you.

Updating Hyper-V to RTM

As is usually the case when you’re under pressure to push a new release of an app for a client, something goes horribly wrong.

What went wrong tonight is simple: my Server Core install was never updated to hyper-v RTM, but windows update did its job fine on one of the client VMs that also runs Server 2008. Suddenly, the whole server is down.

Second install on the core install and still failing. I wonder how I’m going to apologize profusely to my client tomorrow. Oh the joy.

[Update 03:22: License wasnt activated properly, trying yet another install…]

[Update 04:05: Need my bed. Trying an uninstall of the role, followed by an update with the .msu. If that works I’ll reinstall the Hyper-V role tomorrow]

[Update 04:13: Apparently uninstalling the role rebooted the machine which then updated itself on its won with the RTM version. Don’t know if I should cry or laugh. Reinstalling the role now (seeing as there’s one less boot as previously expected, I have a boot to spare)]

[Update 04:27: All back in order, machines are up. Lost 6 hours of my life, less than impressed.]

The testing anti-pattern

I've now finished my previous gig and the guys are busy chasing some recurring issues with the application. Because of its complex architecture, those issues are equally complex to understand and debug.

Most of the code in this application happens around things we cannot put under unit-tests, because they all rely on heavy integration: syncrhonization of data between tiers, integration with external RFID hardware and 3G modems, sqlce and its multiple connections issue, and other equally difficult things to debug without running the system with said external entities. As a result, our code coverage is very low, and while we do have fakes for most of those external entities, we have to think hard and strong about the value provided by tests relying on fakes, or we'd end up testing a fake implementation. Not very useful to say the least.

That made me think of some testing anti-patterns I see recurring a lot on various project, and I thought I'd highlight them. That will let me reevaluate my position in a year time, and I also know that some of the people still invovled in some of my projects are reading this blog, so it will serve as a constructive criticism for their next projects.

1. I'll paraphrase Chad Myers, code coverage is the new LOC/day. Code coverage doesn't ensure quality, and the percentage is just that, a number. It needs to be put into context of the project: some areas do not need unit tests because they don't provide value. If you chase 100% code coverage, you're on a wild goat chase and you should reevaluate your understanding of the value of code-coverage (beyond the marketing bullsh*t).
2. It is more important to have a code-base with low cyclomatic complexity and loose coupling than it is to have thousands of text. Evaluating code quality is not only about testing scenarios, it is also about maintainability, understandability, extensibility, etc. Use NDepend to understand where you need to refactor or rework part of the systems.
3. Finally, and more importantly, I see no value in spending time after your code is released to write unit tests for the sake of it. Because the code has already shipped, you should not do any refactorings to it (or you'd end up with changes that you'd need to re-deploy and re-test, in which case you'll have to ship again, it all becomes a virtuous circle). So you end-up putting code under tests without bringing much value at all (again, except for increasing code coverage, see 1). Unit testing is a tool *during development* that helps you shape your objects and functionality and refactor your code until you get a satisfying result. Writing code aftewards doesn't serve much purpose.

There you are. With the advances like BDD, the focus on unit tests and code coverage by management should hopefully die a much to be celebrated death, as the focus shifts to the real issue: shared knowledge and process, arriving at a common definition of the what and why, and let developers handle the how.

asp.net MVC presentation - the results are in!

The nice people at VBUG just sent me the result of the evaluation forms, and I am very pleased with the result, as a vast majority seems to have enjoyed the talk.

A couple of points were raised by an apparently unimpressed attendee, and as those forms are anonymous I thought I would take the time to provide some feedback here.

The font size was too small to read from the back

The font had been set to quite a big font size, added with a very large DPI. I'm afraid the length of the room compared to the size of the projector made it very difficult to accommodate everyone. If anyone has suggestions to reach to more people while still managing to put 30 characters in the wideness of the screen, I'd be very interested. Any experience from using different fonts? Maybe high contrast with dark background? I'd be quite interested in learning a few new tricks to make it work better.

That said, there were spaces on the front row, and I did ask everyone to confirm my font size was alright with them. I should have indicated this was a strong hint for people to reshuffle based on their sight :)

Discover powerpoint, where are the diagrams?

This one is quite accurate, I do not have powerpoint slides as a rule: unless I have something very compelling to show in a diagram I don't see a point in showing one. I had a slide introduction for the previous version of the asp.net MVC talk I did at DNUG, but I find them distracting and get the audience passive. Especially as for MVC I would end up showing either a product roadmap (I don't think it's my job) or a diagram of MVC, which in itself seems of poor value.

While pictures do speak a thousand words, I think code does speak more efficiently to most developers. So I'd be interested in knowing what people think. Do you prefer a screencast approach of demoing step by step what is going on, or have an introduction to the concept of MVC with nice diagrams, arrows, blocks and what not? I tried both and felt the tutorial approach worked better, but from the presenter side of things it's always difficult to make those judgement calls.

Lots of mistakes in the demo

Yeap, some glitches here and there happened. Some, like the exception thrown when a view is not found, were on purpose to demo a feature, some others were due to my poor typing. On an interesting note, when presenting just like when working, apologizing for something no one has complained about usually seems to trigger complains that otherwise would have been silent. From now on I think I'll stop apologizing for my typing errors and rely on my audience to correct me (which I really like because it means they're reading and understanding the code as I type it. Spot on!)

The examples were poor

Oh, I did like my Bingo game. I'm just sick and tired of the same stuff everyone does with Northwind / NotNorthwind / Southwind. Storefront is there to provide you with an end-to-end real demo and does it so well. I'll stick to my guns on that one, boring things are one of the reasons I don't work in the city anymore :)

Conclusion

What worries me slightly more is the discrepancy between speaker rates and overall session rates, which leads me to think the presentation itself was less than excellent. I think it really comes down to two issues: expectations should be managed to reflect the code-intensive nature of the presentation, and the content is probably slightly too complex, with too many points being presented, including containers, dependency injection, inversion of control, testability, c#, javascript, html, etc.

On the bright side, only one of you has not been satisfied by the content or the presenter, with 67% rating the session as Very Good or Excellent, and 72% rating me as Very Good or Excellent (see my head growing out of proportion!), so a massive thanks to all of you for making this the presentation I've enjoyed the most so far.

P.S. I seem to remember two people chatting and laughing away during parts of the presentation at the back of the room. A good thing I had my back to the audience the whole time or I would have given the eye. Presenters do put a lot of effort in preparing those sessions, if the content or the presenter doesn't interest you, I apologize for failing to make the subject interesting to you, but I'd rather you stayed quiet or left. The law of two feet should apply, even during a presentation.

asp.net MVC presentation

What an absolutely crazy week! I've been working flat-out all week and still have a mountain of TODO: all over my screen.

Thanks to everyone that came to the asp.net MVC presentation. It's a presentation I really enjoy and look forward to give it again to other user groups. I have the feeling that I'll finally be happy with the content the third time I deliver it. And suffice it to say that I'm working very hard to actually make the bingo.net game playable.

Apologies are in order as I'm late delivering the code (will get around to do it, probably around Tuesday) and the slides (slide.txt) and answering some of your emails. Please bare with me while I work through the backlog.

Alt.net UK Conference

Register now! http://altdotnet.org/events/5

Rewriting history?

I very often update and modify my posts until I feel they carry the meaning I intended. With English being a foreign language to me, there are many instances where my posts end-up being interpreted the wrong way or don't represent my message really well.

I'll be migrating this blog over to my own servers quite soon, and I've been wondering if all those edits should be done the way they are now, without history, or if I should adopt a more bliki approach and leave anyone to see the variations and edits I do on posts.

Does historic truth matters to you? Do you want to see my edits? Or do you only care about the end result?

Linq-to-Entities and me: Does what it says on the tin

For those not reading on the web, the subtitle of my blog is the result of a lovely name-calling session by an anon on this site. Proof that it works, another person has now proclaimed that I am indeed what it says on the tin.

The same blog argues that alt.net has turned into the nHibernate mafia, and that we all have a vested interest in nHibernate and are trying to defend our territory. One of the tenets of alt.net is to be pragmatic about the tools we use, and I've delivered projects with nHibernate, activerecord and linq2sql, and will use whichever tool works for the job. I don't have dogma for one tool over the other when they deliver what I need.

And to be absolutely clear, some of my clients will eventually, for better or worse, use the Entity Framework, and I'll have to use that tooling, be it that it fits or not in my personal practices.

On a more positive note, there's been some very interesting comments to my entry. I thought I'd highlight my understanding of the discussion so far. If I've misunderstood those arguments, feel free to respond in the comments or insult me by messenger, I'm always available.

Proponents of L2E argue that this new framework has been developed to provide the same tooling for modelling your entities across your different needs: reporting, data access, etc. As such, it should be seen as a tool that lets you re-use knowledge across models. Furthermore, it should not be understood as a tool to create global entities shared across applications.

This could very well be the case, and indeed bring benefits for people using Reporting Services and other data-centric tools that are apparently a pain. But if we see L2E as a tool, then for reasons that have been highlighted previously, they won't fit my toolbox because they do not support the development model I have adopted.

That said, other people still look affectionately at the idea of a global model for your application / applications. My projects tell me those models fail and my experience shows me that a DTO approach to boundary crossing is more effective.

I have expressed concerns at the fact that L2E has been at the core of  other frameworks (like ado.net data services), because it brings the fundamental idea that the same model could be exposed as a REST service, sent over a WCF service to another windows client, and put in a can of Coke to the moon. Doing each of those things represents a completely different set of challenges, each with a different model. Maybe if LinqToEntities could fit in my toolbox, I could reuse it to model every single of those different entities I need to have for each boundary in my application. But I don't believe the power of the designer is going to solve any of my issues, and will probably introduce more.

I stay unconvinced but I'm overall happy to realize that many proponents of linq2entities have an understanding of the issues with a unique entity data model and with sharing of models.

The Entity Framework - don't get fooled in what is wrong about it

[edit: modified text slightly to more accurately reflect my point and remove references to Julia being fooled, which apparently has been interpreted as Julia being a fool. Apologies.]

I'm off to bed, but thought I'd end up the day on a note. There are many flaws in the programming model adopted by the Entity Framework and they've been documented enough. But this is not what makes me cringe the most.

The Entity Framework team responds to the vote of no confidence by proposing fixes to programming issues in v2, talks of openness in the design of the next version, and have got people thinking that we object with the programming model. They even suggest that it's alright for Microsoft to deliver a tool that violates best practices established by people that built real systems.

[edit: I don't believe this is done with malicious intent, but I do believe there is a fundamental misunderstanding of the arguments that have been put forward, both by the EF team and their supporters and by the signatories of the letter]

The idea that a conceptual model can represent everything for everyone through designer-generated angle-bracket files is the issue. The fundamental of selling your product as one model crossing tiers and being standardized to all is a sweet dream that will end up biting anyone getting in contact with such a system. When Microsoft says transparently, I hear painfully.

The EF team explain how to fix the syntactic sugar without addressing the elephant flaw in the model is equivalent to telling people disagreeing with the one conceptual model to rule them all that they're just nitpicking over syntax. It's quite amazing that the people voicing their anxiety at the ripple-effect of introducing EF are being discarded as a small minority of weirdos that shouldn't complain because their way is not being adopted until v2. The reality is that a majority of those people are leading the industry in interesting directions discovered through experience and reflection, and their ripple effect is wide. . There is no wonder why TDD and BDD (and DDD and DDDD and all those acronyms I hate so much because of their opacity) all started with a couple of people, not with a couple of tools and designers.

Microsoft has a responsibility, because of its size, to not screw the people that are trying to promote a better craft. When those people react to a technology like they have with the Entity Framework, they should be listened to, because by delivering yet another monster (sharepoint anyone?), Microsoft may generate business but in the process degrade the overall quality of their development ecosphere. In the long term that may just end-up killing them, as the market will decide on better, simpler and more efficient tools. It's the law of two feets. But this movement takes years and impacts everyone that has to maintain a system.

As for Entities, they exist as several transpositions adapted to not only the programming model but also the context in which you use them. My notion of a user and your notion of a user only share a couple of trivial rules. If you ever, ever try to come up with one model that covers everything, you'll be too flexible or not enough, and your project, and the projects depending on your project, will fail. Full stop. It's been tried and tested. It is wrong. Like putting mustard in your corn flakes.

[updated for clarity and minor adjustments]

Jesus is back and His name is... svn?!?

Picture worth a thousand bibles.

Linq2sql running on Sql Compact Edition - calling on VistaDb to clean-up their act

There is a lot of misunderstanding on this subject. Even competitors of Microsoft seem to not understand fully what Linq2sql is made of or what it actually covers. One of these competitors is Vistadb that says on their product comparison:

SQL CE users will have to wait until the Entity Framework release before they can use LINQ against a SQL CE database.

I sent them an email to warn them that their comparison was erroneous, and an exchange has started in which they've assured me I was in the wrong and have neither acknowledged the confusion nor updated their comparison. As such I feel inclined to bring the conversation to the community, to get knowledge out there. I have not received their authorization to reproduce the exchange, so I'll have to represent as accurately as I can, in my own word, the different points they made. And I hereby invite them, and you dear reader, to the conversation.

Before you begin reading this, please note I do like the work the vistadb guys have been doing, I think it's a great internal database, and I probably would use their product still. But with greatness comes responsibility yada yada.

There is no provider model in linq2sql

This is an easy mistake to make if you don't spend your time in reflector. Linq2sql *has* a provider model that has been marked as internal late in the process, as described on the Wayward Weblog. If I was to guess the reasoning, I'd guess that there would've been a conflict of interest for partners to support both the Titanic Entity Framework model that leverages updates to the core ado.net classes and a provider model where they would've had to rewrite the sql code generation from the ground-up in linq2sql.

But I would concede that, as it's not public, for all intent and purposes, there is no provider model *you can build against*.

Linq2Sql gives you a Visual Studio GUI and a mapping tool

This is accurate, and very relevant to our conversation. There is several aspects to linq2sql.

• A provider model, with a provider implementing access to Sql Server 2000, 2005 and 2008, as well as Sql Compact Edition 3.5. This is the bit of code responsible for translating between the model and the sql code
• An abstract mapping model defining types such as MetaTable, MetaType and MappingSource, that let you implement different mappings. Linq2sql ships with two of those, one for xml mapping files, one for attributes.
• Visual studio ships with a designer that lets you generate an xml mapping file through a point-and-click UI. This only supports the full-fledge Sql Server, and this is where the confusion may be coming from.

So there is a bit more than a GUI and a mapping tool. It's a GUI, a mapping model and a provider model.

Sql Compact Edition queries don't support Linq, the compiler does

Well I've struggled quite a bit to understand that one. Linq queries are compiled by the compiler as extension methods or interfaces defined by the implementations of Linq (Xml, object, Sql, etc). However, I fail to see any connection with Sql Ce itself, as the one querying the database is the provider that, indeed, supports Linq2sql just fine. The provider is indeed distributed with Sql Ce 3.5.

Microsoft does not use Linq2sql as a term that covers Sql Compact Edition and it's unsupported

I don't see how it relates to the technical conversation. And the download page of Sql CE 3.5 specifies the following.

SQL Server Compact 3.5 introduces a host of new features including LINQ to SQL support

Again, it doesn't seem like unsupported to me.

Conclusion

Vistadb is a strong product in its own right. The product comparison however contains a mistake and the company hasn't responded to the two emails I've exchanged with a catchall email address.

All in all, this highlights two points. Microsoft has a communication problem around Linq2sql; Iif your competitors don't understand your product well, imagine your customers. Secondly, if you want to put product comparisons you should *really* double-check your facts. Responding in person to emails rather than through a customerservices@... address, and double-checking before responding the second time would probably have kept me a bit happier.

The Entity Framework paves the way to years of uneducating the masses

This is in substance the bitter taste that's left in my mouth as EF v1 gets ready to be released.. I've been debating on this topic in user groups, meetings and within my clients: adopting EF as it stands would be a mistake as it introduces fundamental issues in the way we write code and in the way we design our architectures. We will spend years undoing the massacre done by introducing that technology as it stands, just like we still have to suffer DataSets today.

That's why I signed the ADO .NET Entity Framework Vote of No Confidence.

And today, it was announced that the Entity Framework team would adopt a transparent process in the same way as the ado.net data services team has. In this respect I'll have to remark that the ado.net data services team took the decisions they wanted to take, even when the community advised against them.

Furthermore, the objections that were made against the Entity Framework have been around for a while and apparently didn't make it into the V1.

I'll try and have an open and positive attitude towards this opening-up, but I'll notice that already there's a push within MS to adopt the entity framework everywhere. If you push for adoption of your v1 in the company and respond to criticism by promising to fix  fundamental scenarios in v2, you're doing more damage than good, and this is why I have a trust problem vis-a-vis the Entity Framework and its design team.

A real 3d-enabled web browser for WPF?

I know, some of you think that the browser control in the latest WPF 3.5 SP1 is the dog's bollocks. Sadly, it suffers from its origin as a wrapper around good old GDI and the lack of GDI redirection imposed by supporting WPF in Windows XP environments.

One thing I keep track of very closely is what the mono guys do. This is a fantastic pool of resources, skills and code, and if I had time to hack I'd probably join one of their many projects. And on their feed I came across Alp's post describing a WebKit-based 3d web browser. I can't wait to have a play with the code.

Technorati Tags: mono,c#,wpf,webkit

Alt.net London Beers #2 - 17th of June 2008

It's this time of the month again, and we continue with the tradition of organizing alt.net beers events monthly.

As usual, it's casual, it's about chit chat on alt.net things and its about beer.

The venue has kindly reserved a couple of tables in their upstairs bar where we'll be having some food and of course beer.

Don't hesitate to mail the details around, the more the merrier!

The Blue Posts
18, Kingly Street
London W1B 5PX

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Technorati Tags: alt.net,London,altnetbeers,altnetuk

NxtGenUG PreFEST08 Dinner & Fest08

NxtGenUG is the most thriving user group community around. They're organizing a dinner tonight, so come and join if you're around Reading (only 29 minutes on the train from London)

And of course, tomorrow is a day of pure geekiness with the Fest08 event in Reading. Come say hi!

Hello twitter?

Craig has been selling me twitter over the last few months and I always kept it on the back of my mind. From this morning twitteroo is installed and I'll be able to start moaning on my twitter feed about the poor QoS as soon as I get it. Right now it just looks like a web-based IRC to me.

Side note, when is too much information too much? Mailing lists, messenger (and often during the day visitors of this blog chatting away, usually introducing themselves with asdf or the time-proven testing), maybe I'm overcommitting?

Agile smell

Anthony talks about a potential agile smell and the concept of self-organizing teams. As with his brother's blog, I still can't figure out how to post a comment so it ends up on my blog. If I was to bother with putting categories on my entries, I'd probably have one specifically for commenting on other posts when I've been too dumb to find the reply or the register button.

Let's first separate Agile (as an enforced, recognized and lucrative book publishing business, as well as quite a bit of ego and a general lack of understanding or intelligence in applying the ideas), agile (as a bunch of methodologies you pick and choose from to try and get as many benefits as you can out from what others have spent years experimenting with, and that we alt.netters would consider the pragmatic choice), post-agile as a poorly worded (imho) variation of pragmatism, and scrum (as one particular self-organizing methodology, one of the most popular but also one of the most badly applied). They each represent different things and different steps you can and should follow in becoming more agile, and everybody should try to get more agile even when not wanting, refusing or considering being past the stage of, Agile.

Back to Anthony's post. He talks about a "conflict" with someone telling him that he should have chosen a story to pick on his own because teams are self-organizing, and Anthony argued that without prioritizations he should ask before committing to the work.

I'm not entirely sure which variance of agile that company is using, but here's what we do here. Stories are written on the wall and are negotiated with the client, and doesn't involve the dev team much at the early stage outside of simple feasibility study (when we're lucky). They get used for us to produce both the scenarios for the tester's acceptance criterias and the product backlog.

The product backlog is the one being prioritised: high-level functionality cards of a couple of days, and the prioritization is done by us from the knowledge we extract painfully from the project managers. Sometimes they even come and do it themselves, but sadly that's as common as a solar eclipse.

From this, we commit at the beginning of the sprint to the amount of work we think we can deliver. After a couple of sprints we know roughly from our estimates how many virtual hours we deliver per sprint, aka how many of the hours we have estimated we manage to deliver. This is usually quite accurate even though the number itself doesn't mean much at all.

The team is self-organizing from that point because the *team* has committed to the *whole* of the sprint backlog. If we had over-committed we would've de-scoped. In that sense, at the stage of a daily stand-up, I'd agree that a team member asking what to do next is usually a practice smell:

• Priorities of tasks mostly don't exist as we're committed to all of them
• The ones that need to be worked on first are based on dependencies rather than priorities. If you ask you probably forgot what depended on what. With short sprints, that's the last thing you would forget when you've spent 3 or 4 hours deciding all of those on the Monday.

We use the wall for roughly clustering tasks that are inter-dependent, and the bottom of the wall for the nice-to-have. When you commit to a task, you commit to the team that you're wishing to do a task, so you probably don't have a reason to ask for permission.

The final thing that I've experimented on my latest project is to decouple the sprint backlog maintenance and the daily stand-up. It's now a real-time wall: you add, remove, complete and reshuffle tasks when you feel like it, the wall is visible and people will see the changes as they happen. The daily is a summary of all those movements: this relieves the pain of updating the wall, makes it more entertaining, and no one asks what to do next because they've either not finished their current task yet or they've already chosen their new one.

Being agile share many of the tenets of alt.net: flexibility, lookout for the best solution, pragmatism. In that respect I'll agree with Anthony that an Agile Anal can be annoying. But on the other hand (and I'll leave that to another post), only the teams that tried and mastered Agile can allow themselves to deviate to agile. If you've not tried hard enough a change in mentality in the way you work, you will fail, and what some would call "adapted agile" I call "bad habits are back".

[Updated: s/Jason/Anthony]

Pdc2008 here I come

One of the first thing I did this morning was to make sure I had registered for the 2008 edition of the Pdc.

Any brits travelling to LA or any alt.net guys want to organize an unconf, let me know.

Now they need to open the registration for TechEd Europe and I'll be booked for the year.

Technorati Tags: pdc2008

Retrospective on my asp.net MVC talk

I'm publishing this a bit late, but I took a few days (a whole two of them) without working. How refreshing!

In an effort for a more transparent process, here are a few things I think went well and didn't go too well. If you've been at the talk I would absolutely love your criticism. Practice makes perfection, but before that it makes for nicer presentations and a less worried Sebastien!

Preparation god damn it!

The font-sizes were all wrong in everything but the code-editor, this is quite unacceptable and certainly not like me at all. So be prepared if you install vs 2008 SP1 beta, it will reset all your settings. That explains the lack of proper configuration in visual studio. And of course, a problem never comes alone, vs refuses to start under my Presentation account that is set with ridiculously large DPI setting. But it all comes down to me installing this stuff too late, which left me no time to make sure everything was configured properly. Apologies to the audience, I should have had a VM up-and-ready with all my content. And apologies to myself for installing a beta service pack on my main development machines.

Tools

All the usual presentation tools were not installed on that laptop either, so no ZoomIt and no Keyboard Jedi. Again, with a reinstall of vista a couple of days before, I just didn't have the time to get it right.

One thing I find difficult is choosing a screen mode. When showing code, I want to show you my Visual studio and whatever other programs get spawned by it (ie, firefox, the command prompt) while still seeing them on my screen. For powerpoint, I want to keep presenter-specific stuff from your eyes (a timer, some notes, and in general the whole content of the slide you'll see appearing as I talk).

I need a hybrid between Clone and Span modes. I may have something working, so my next talk will guinea-pig the idea. I'll blog about it after trying it out. :)

Not having slides...

Some people didn't completely see how the asp.net MVC and the REST part of the talk connected together, and maybe I should've introduced that at the beginning on the slides. But if you know me, I don't like slides and will avoid them at all costs.

This is the first talk I give where I put some content on slides, to refresh everyone on MVP and MVC and how the models differ. I like how visual it makes the explanation, but I'd rather manage to do it graphics only, with no text whatsoever. That requires more work, a tiny bit of animation and very good graphics. Nothing that can't be done with enough time for pimping it up.

Body language

I used the MacBook remote to change slides, and the freedom to move around to move slides is next to none. I also find that having the remote to hold from the tips of my fingers helps me avoid leaving my hands hanging. Hold something to keep your hands at chest level, it puts your body language into explanation mode. Relax and put one hand in your pocket and you switch to opinion mode.

Eye contact is the best tool to calm anxiety. You'll always find a couple of people in the audience being very expressive, that lets you judge the rhythm of the presentation. There's nothing worse than an expression-less audience.

Messy content

I'm a bit in-between two waters on this one. The whole point of the talk was to see what toolkits you can use today to do REST applications, but, for various reasons, I fit in there an introduction to asp.net MVC as a first part. That just doesn't flow well, and I think I'll split those two in two different presentations: asp.net MVC introduction (I have some AJAX stuff to make that presentation complete), and REST today, rest tomorrow. They can both stand on their own feet, and it would leave me more time for doing what I prefer doing: talking rather than coding and rushing.

I'm not funny

I tend to make jokes during the talk, they're usually completely spontaneous, but they fall flat every time, except for a few friendly grins from people I've met or talked to before. I shall prepare my jokes in advance and only use them after having tested them. But not on animals.

Speak more slowly

My voice level seems to be alright, but I speak too fast. And I have those pet words that creep in, amongst them "I think" (very annoying one I have a lot of problems getting rid of, even in day-to-day conversation), and Ok (very patronising, hate it, think I managed to mostly kick it off my presentations).

It's quite funny how the brain gives you those little fetish words. I think they creep-in because they trick your brain think there's a rhythm to what you're saying, when simple punctuation and sentences should be enough. It may also be the case that they give your brain enough time to reformulate when you're mid-sentence and unsure about what to say next. Again, preparation is the key.

Have different solutions, not different projects

This one bit me during the presentation. As I prepare the code for all the major steps, I end up with the same project at different stages, and I made the mistake of keeping all the projects in the same solution, often resulting in the wrong code being ran when pressing F5 and the wrong files being shown when I expected to show some code.

From now on, I'll keep all the projects in separate solutions.

Conclusion

I really like giving talks. It is a bit frustrating to come up with new material every time and only use it once, as you don't get the opportunity to retrofit what you learnt from presenting it once. Hopefully that will change as I get new speaking opportunities.

Presenting at the London .net User Group: Put your webforms to REST - how to build rest-y architectures with .net

What:
With the raise of the web 2.0 meme, more and more web applications claim to support REST architectures. We'll explore together what is REST and what is not, and how we can write a testable web application that supports the REST concepts on the asp.net platform, with a code-intensive overview of current toolkits (asp.net MVC and others).

Where:
MRM Worldwide London
76 - 80 Southwark Street , Bankside Studios, London SE1 0PN

When:
Tomorrow Wednesday the 21st of May, 18:30

Why:
This, I have no idea of :)

That is, if I get Visual Studio 2008 SP1 installing properly on my demo laptop, which is no small feat in itself, or face a frantic rewrite of some of the presentation tomorrow.

Reflecting on my last project

Today is a day off, as I've accumulated 36 hours of work between Monday and Tuesday and needed some rest. The last project I've been working on has been one of the most interesting I've had in a long time, not only because I took more responsibilities than usual, being both a lead dev and as a scrum master, but because of the amount of technology we've fetched in one app. To give a quick run-down:

• Fluid database design with an object-based linq2sql database (no dbml file and no sql files in the whole project)
• Sql Compact Edition
• ado.net synchronization services to sync to a central database, and hopefully the sync framework for multi-party syncrhonization
• WPF all the way, with a ViewModel way of developing
• Castle stack, for Windsor and a bit of DynamicProxy2 love
• 3G support for an always on experience

I've learnt quite a few things in the process, so here's a few reflections for my own benefits.

• When you don't know what you're building, you're going to have a hard time knowing when it's done
• Working under pressure can be fun, but it's exhausting and it does highlight a failure in the planning part. We're getting better but we're nowhere near there yet
• It's fun to see people with a background go around in WPF. It always starts quite code-centric and evolves into more XAML as time goes by
• I still don't see people using Blend for anything meaningful. There's a wide range of reasons why, from crashes to not liking esoteric Xaml to the recording model. It doesn't go down well with either populations right now, at least as far as WPF is concerned.
• The only reasonable way to monitor the correct use of patterns and abstractions is to do it continuously. Not paying attention to the code base and coming back with changes weeks later is not a good idea, and a complete failure on my part. I need to get better at agreeing, explaining and enforcing design decisions.
• No one can work on several projects within a company and stay focused. This doesn't work at all. From now on, I will flat out refuse to work on  something else in the same day. If you want my time for two projects, my minimum time unit will be a day. Interruption decreases my productivity so much it's unreasonable, and the project (and my nerves) suffer.
• Frameworks that hide all of their internal implementation suck big time. Understanding object tracking in linq2sql is not easy or enjoyable, and bite you. Badly.
• Frameworks that show all of their internal implementations suck big time. Castle Windsor (at least RC3) throws exceptions in all the wrong places, and make dealing with registration more painful than it needs to be (when it works at all).
• Designers and UE people *need* to be involved throughout the process, and work on the same stuff as the rest of the team. The way people think they can go off and work on the UE or the design on their own schedule, with only validation from tech (when they don't send the work done the day before a release) is driving me absolutely insane. This doesn't work for them (we can tell them how much more flexibility they can have in their own design), it doesn't work for us (they provide diagrams of stuff we've already delivered, or stuff that is completely limiting the capacities of the platform). It's the typical waterfall model, and fall and fail it usually does.
• Someone needs to wake up and realize that the technology is not there to support the design, and the design is not there to put a nice face on technology. They're two sides of the same silver coin, they need to work together to deliver. That's what Apple does and it works great.
• I'm always amazed at how little is still invested in most of my clients companies around supporting other development teams. With a core team of a couple of peoples working to support other teams and evangelize the company's infrastructure, any company would save *so much time* on all other projects, from enforcing good standards, deployment procedures, automation etc. Think a few weeks per project.

Overall, a very good project, a great team and a freedom that I don't have very often with clients. I think it'll be difficult to move to my next project, the comparison will suffer!

alt.net drinks moved, only slightly

Got a message from Catriona, and the original location for our alt.net beers event was fully booked, so it's now around the corner from the previous location. See the original post for the details.

Implementing INotifyPropertyChanged with DynamicProxy2

22:30 and still working on various bits and bobs, so I thought I'd take a well deserved break to tell you about one nice way to implement INotifyPropertyChanged, the one and only interface any class that will be bound in WPF should be implemented.

I used to (circa .net 2) not see a bit issue in this kind of code.

public class MyClass : INotifyPropertyChanged

{

    private string _myValue;

    public event PropertyChangedEventHandler PropertyChanged;

    public string MyValue

    {

        get

        {

            return _myValue;

        }

        set

        {

            _myValue = value;

            RaisePropertyChanged("MyValue");

        }

    }

    protected void RaisePropertyChanged(string propertyName)

    {

        if (PropertyChanged != null)

            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

    }

}

But I've been badly spoiled by automatic properties in C# 3.0, and this all sounds like a lot of noise. How great would it be if we could instead simply have the following.

public class MyDreamClass : INotifyPropertyChanged

{

    public event PropertyChangedEventHandler PropertyChanged;

    public string MyValue { get; set; }

}

Definitly much cleaner.  We're going to use DynamicProxy2, which is part of the Castle framework, and is used amongst other things in nhibernate.

The process is quite simple. You ask a ProxyGenerator to create a type for you, and pass it an interceptor object that will... Intercept any call!

First, let's clear up our class. Because the object generated by DP2 inherits from the original type, it needs to have a virtual modifier on the property. Furthermore, I wanted to add an attribute to specify which properties were to trigger the notification.

public class MyBetterClass : INotifyPropertyChanged

{

    public event PropertyChangedEventHandler PropertyChanged;

    [Notify]

    public virtual string MyValue { get; private set; }

}

Now, let's see how we create the object.

static void Main(string[] args)

{

    var proxy = new ProxyGenerator();

 

    MyBetterClass myClass = proxy.CreateClassProxy<MyBetterClass>(new NotifyPropertyChangedInterceptor());

 

    myClass.PropertyChanged += (src,prop) => Console.WriteLine(prop.PropertyName);

 

    myClass.MyValue = "testValue";

}

Fairly simple so far. Now let's see the meat of the code, the interceptor.

public class NotifyAttribute : Attribute { }

public class NotifyPropertyChangedInterceptor : IInterceptor

{

    public void Intercept(IInvocation invocation)

    {

        // let the original call go through first, so we can notify *after*

        invocation.Proceed();

 

        if (invocation.Method.Name.StartsWith("set_"))

        {

            string propertyName = invocation.Method.Name.Substring(4);

            var pi = invocation.TargetType.GetProperty(propertyName);

 

            // check that we have the attribute defined

            if (Attribute.GetCustomAttribute(pi, typeof(NotifyAttribute)) == null)

                return;

 

            // get the field storing the delegate list that are stored by the event.

            FieldInfo info = invocation.TargetType.GetFields(BindingFlags.Instance | BindingFlags.NonPublic)

                .Where(f => f.FieldType == typeof(PropertyChangedEventHandler))

                .FirstOrDefault();

 

            if (info != null)

            {

                // get the value of the field

                PropertyChangedEventHandler evHandler = info.GetValue(invocation.InvocationTarget) as PropertyChangedEventHandler;

                // invoke the delegate if it's not null (aka empty)

                if (evHandler != null)

                    evHandler.Invoke(invocation.TargetType, new PropertyChangedEventArgs(propertyName));

            }

        }

    }

}

And that's it. Get the field in which the event is stored and invoke it whenever a property has been modified.

Thought of the evening

MSBuild + SqlCompare + DataContext == FluidDatabaseDesign

The tale of the 6.4 Megapixel desktop

Just upgraded my development environment, here's the picture.

The laptop looks tiny next to the screen, but it is in fact a high res MacBook Pro, 1920x1200, driving as a secondary screen an Apple Cinema Display 30" for an added 2560 x 1600.

That's freakin' 6.4 megapixels of vista goodness! Surprisingly enough, Aero runs without a hitch.

Couple of other interesting points: new apple keyboard as I fell in love with the feel of the MBA keyboard, the mouse is not the one i usually have (but ran out of batteries). And Prada sunglasses for the one day of sun we've had in London so far.

As for drinks, the coffee mug is the property of the client at which I keep this equipment, and the can of Redbull kinda explains the name behind my company name: caffeine IT :)

IIS and asp.net URL validation weirdness and links

In my Migrating to IIS7 post, I highlighted that building REST frameworks that do meaningful things with Urls is hard on microsoft's platforms.

I encourage you to go and read the comments left by Mike Volodarsky on the issue. He's a Program Manager at Microsoft. Having people from the team building IIS7 responding to people like me highlighting issues shows how some teams really engage proactively with their customers. Kudos!

The other team at Microsoft that understand REST a bit (and IMO the most out of all the teams working on this), is the Astoria team. And of course, because they do funky stuff with their URLs, they hit the same issues as me. So here's a link on how to deactivate some of the checks asp.net does. Nasty registry editing...

I really wish asp.net could recognize when an IHttpHandler does not want validation and let it handle the request, its validation and etc.

Alt.net London Beers #1

[Update: new location, see below]

Here's the latest development. The alt.net London Beers event is being moved!

Skills Matter is organizing a talk by Gojko Adzic on the Castle Framework on the day we originally planned for the drinks. As everybody has shown strong interest in attending both events, Skills Matter has been kind enough to help us organize the drinks in the Crown Pub in front of their office, so you can now attend both events.

Not only that, but they have also opened the possibility for another presentation on an alt.net subject, so if you feel like presenting, drop me a mail!

I have to thank Catriona at Skills Matter for sponsoring the alt.net London Beers event and inviting all the alt.netters to attend the Castle presentation, as well as Gojko for suggesting the merge of the two events.

So here's the recap:

• What: Alt.net London Beers #1
• Where: The priory bar in St Johns Square, right by Farringdon station
• When: 15th May 2008 from 20:30

We'll probably move back to the planned Tottenham Court Road location for our second meet, on the 16th of June. Keep your calendars open!