Software Development

The circular logic of the WSS Lists Webservice GetListContentTypes call

Andy Burns, , , 6 Comments

So, I need to get a list of the content types applied to a library. The Lists webservice has a call for this:

<getlistcontenttypes xmlns="http://schemas.microsoft.com/sharepoint/soap/">
<listname>string</listname>
<contenttypeid>string</contenttypeid>
</getlistcontenttypes>

So, I’m connected to a site, I supply a list name to identify the list… …but what do I give as a contentTypeId? I don’t have a f$%king clue – I was calling this function to try to find out what content types were valid!

Well, good news. It doesn’t seem to matter what you put in, you always get a list of all the content types on the list. I used the following code…

WS_Lists.Lists lsts = new WS_TestApp.WS_Lists.Lists();
lsts.Credentials = System.Net.CredentialCache.DefaultCredentials;
XmlNode node = lsts.GetListContentTypes(libraryName, contentTypeID);

I figured that maybe they wanted the base content type for what I wanted back, so I tried setting contentTypeID to documents (0x0101) and got back a list of all the content types. I then set contentTypeID to “fish”, and still got back a list of all the content types. As far as I can tell, the second parameter doesn’t do anything.

Side note: The first content type returned is your default content type.

Side note 2: There doesn’t seem to be an easy way of identifying non-visible content types…

The circular logic of the WSS Lists Webservice GetListContentTypes call

Are web services really that great?

Andy Burns, 1 Comment

So I’ve been working for the last few days using SharePoint’s web services extensively. They are pretty neat insofar as they offer a very public set of interfaces – the communication is pretty much human readable (for a given geekiness of human).

However, a couple of things have struck me. First was the bandwidth needed. Some of the calls I’m making were getting back 50k responses – and for a simple action in the app I’m working on, I could have to make lots of those just to display a form to a user. 1Mb downloads to show this form were likely – so this isn’t great. Presumably, enabling compression on the web server should reduce this considerably (looking at the XML in the file, it seems to have a high redundancy), but only at the cost of extra processing. Still, I can live with that.

The second, and in some ways more fundamental point, is that I find myself having to write wrappers for the various web services. I know, calling a web service in C# is dead easy, and that’s great, but the response -yuck! Everything seems to come back as lots of XML. And I do mean lots. I don’t actually want to deal with reams and reams of XML. Object oriented programming sort of implies that I should be trying to deal with objects. After all, that seems to be what much of ADO.NET is about – presenting data as objects.

So, for comparitively well known web services, can’t we have a pre-built wrapper so that I’m just dealing with objects? Both in and out. That way, well, if I want to talk to the web service via XML, directly, well, I can. If I’d sooner work with objects, then I could do that also. Just at the moment, there seems to be an asymmetry – I supply an function with parameters and it produces the request in XML. Then when I get the response, well, it’s just XML.

Hell, isn’t that what SOAP is all about? A common communication layer between remote objects?

In fact, thinking about it, some of the web service requests need XML put into them too – but that’s CAML, and another gripe entirely.

Are web services really that great?

I'm now a 'Professional Developer'

Andy Burns3 Comments

MCPD Logo

Presumably, everything I’ve written over the last 7 years has been amateur (well, some of it was, certainly). This is in addition to my being…

MCTS Logo

To be honest, I still feel I’m being firehosed with information about Microsoft stuff, and that I’m struggling to keep up. But I guess that the point of such certifications is that they demonstrate a level of ‘minimum competance’ – that is, the holder still might be “Good” rather than “Brilliant”, but at least you can be fairly sure that they aren’t “Completely Inept”.

Anyway, I learnt a lot doing the Professional Developer exam – or rather, reading the course materials. The exam itself, well, I felt that some of the questions were a bit too technical, while the book seemed to cover a higher level view of the system (at least, in it’s good bits). See my comments on the book I used.

I'm now a 'Professional Developer'

Abject Failure and Complexity

Andy Burns, Leave a comment

I’ve been meaning to post this for ages – Marus Ranum on why information security is an abject failure. And he’s right – the problem is the complexity of todays interactions, both at a protocol and language level.

To me, the problem is one of failure of KISS (Keep It Simple, Stupid). Applications and protocols haven’t been, and we’ve had more tacking together of technologies, and expansion of complexity of everything.

I mean, consider what languages you needed to know 10 years ago, and now:

Then:

HTML 3.2, JavaScript maybe, Perl if you’re brave, SQL if you’re a hero.

Now (Microsoft Stack only):

HTML 3.4, 4 (various favours), XHTML, XML, XSL, XPATH, JavaScript (much more complex), ASP.NET 2.0, C# or VB, .NET frameworks 1.1, 2, 3 and 3.5 (soon), ADO, SQL, CSS, ‘AJAX’

That’s just the languages and base technologies – never mind getting into a higher level of software (e.g. SharePoint). Or non-MS technologies – Ruby, Rails, Python, Java in various forms…

It’s similar in protocols…

Then:

HTTP, HTTPS, FTP, SMTP / POP

Now:

HTTP, HTTPS, FTP, SMTP / POP, SOAP, Web Services (plus various extensions), IMAP, Various Peer-To-Peer protocols, Various Instant Messaging protocols

(Yes, those are fairly high level, and from different levels of the stack – but still, you’re expected to know about them.) (And yes, I suppose you’d need to know a bit about TCP/IP and IPSEC)

Does that sound simple? Does my granny skateboard?

(Well, no, but that would be so cool).

Security will be impossible with such a complex, varied stack of technologies, and developers simply won’t be able to specialise enough to know how to make secure enough applications. It alarms me how wrong people are getting password storage alone – I mean, this stuff has been known since the 70’s. If they can’t get that right, how will they manage with a such a deep and varied set of tools?

Abject Failure and Complexity

Add an event handler

Andy BurnsLeave a comment

I keep using this snippet of code:

if( window.addEventListener ) {
window.addEventListener("load", fn, false );
} else if( window.attachEvent ) {
window.attachEvent("onload", fn );
}

It’s just a tidier way of attaching a function ‘fn’ to an event. It also allows multiple handlers per event. There could be another ‘else’ where we just assign the function to an event (e.g. window.onload = fn ) but that would only support one handler per event.

Add an event handler

Adding Snippets in Visual Studio

Andy BurnsLeave a comment

I keep forgetting how to do this, and have to do so every time I want to create a new SharePoint workflow.

  1. Open Visual Studio.
  2. Right click on toolbars and ‘Customize’
  3. Click ‘Commands’ Tab.
  4. Click on the ‘Tools’ category.
  5. Add the ‘Code Snippets Manager’.
  6. Add ‘C:Program FilesMicrosoft Visual Studio 8Xml1033SnippetsSharePoint Server Workflow’ to your snippets
  7. It should be straight forward from there…

Comments from my old blog:

Are you using your own project templates? I’m curious because using the MOSS Workflow Project templates (both state machine and sequential)–the templates that come with the MOSS SDK–and I have the snippets already available to me.

Anyway, just throwing that out there.

By Peter {faa780ce-0f0a-4c28-81d2-3 at 17:30:01 Monday 10th September 2007

Nope, these are the ones out of the SDK. I’m not clear why, but in some VMs that I use the snippets aren’t immediately available after I install it. And normally the ‘Code Snippets Manager’ is already available too – but not always. I haven’t figured out what factor causes these things to occur :/

But yes Peter, you’re right – normally they should be available.

By Andy B at 11:16:21 Tuesday 11th September 2007

Adding Snippets in Visual Studio

The Pain of VB6

Andy BurnsLeave a comment

So, I’ve been forced to spend a couple of weeks modifying some code I wrote a couple of years back, in VB6. One word – crap. That’s the word for both the language, and my code.

Visual Basic 6 is just painful to code with. ‘Dim’? I’d say. The inability to return arrays from a function keeps catching me out. And I detest the way that no matter what I do, I can’t stop Visual Studio beeping errors at me and show message boxes when I try to leave an incomplete line so that I can copy and paste a variable name.

The worst part is, though, that it doesn’t really promote good program structure – well, not to me anyway. I’m often not entirely convinced that Object Oriented Programming actually reuses much code – but it does force it to be structured and organised. My code in this project, well, it isn’t. It’s suffered that sort of ‘evolutionary’ growth rather than proper, designed expansion. And some of it has to excapsulate an API that is archaic, irritating, and dangerous. (I’ve been debugging for memory leaks, dammit. Yes, this API forces me to allocate/deallocate memory).

What a sucky language. It really makes you appreciate Java/C#.

The Pain of VB6