I’ve just updated Catfood.Shapefile, my ESRI Shapefile parser for .NET, with PolyLineM support thanks to a contribution from Stephan Stapel. The solution for the new version has also been updated to Visual Studio 2010.

Download Catfood.Shapefile.dll 1.30 from CodePlex.

Mark Jackson, my co-founder at Cucku, is blogging re-mastered debugging tips from StackHash at infopurge.tumblr.com. StackHash is now an open source project on CodePlex and all of the great content from the original site has been taken offline. This new project is a great resource for debugging on the Windows platform, especially post-mortem crash dump analysis. If that’s your thing do yourself a favor and subscribe to Mark’s blog.

Wasted far too long on trying to get WCF to work with custom basic authentication this week. Custom in the sense that I need to look up the username and password in a database and not have IIS attempt to match the credentials to a Windows account. Given how well WCF 4.0 supports RESTful services in general it’s a bit shocking that basic auth over SSL isn’t supported out of the box. It seems like you should be able to derive and hook up a class from UserNamePasswordValidator, set the transport clientCredentialType to Basic and be ready to go. I’ve heard that this works for self-hosted services, but no dice in IIS.

Basic access authentication is a simple protocol and so in the end I added a helper method that checks for access (and in my case returns the user information for later use) at the start of each call into the service. It’s very simple:

1. Check WebOperationContext.Current.IncomingRequest.Headers for an ‘Authorization’ header. If it’s there decode and validate the credentials.
2. If the header is missing or the credentials are incorrect add the WWW-Authenticate header to the response - WebOperationContext.Current.OutgoingResponse.Headers.Add("WWW-Authenticate: Basic realm=\"myrealm\""); – and then throw a WebFaultException with a 401 Unauthorized status code.

This triggers a browser to prompt for your username and password and then try the request again. When calling the service in code you can add the ‘Authorization’ header preemptively and skip the 401 response entirely.

I’ve just moved ITHCWY comments over to Disqus. BlogEngine.NET now supports Disqus out of the box, but doesn’t export comments to anything that Disqus is willing to eat. I’ve knocked up a quick converter that takes a full BlogML export from BlogEngine.NET (and at least in theory any other source of BlogML) and converts the comments to WXR. You can import the WXR file under the Generic option in Disqus.

The tool is a Windows console application that takes two parameters, the BlogML import file and the WXR output, i.e.:

BlogMLtoDisqus.exe C:\BlogML.xml C:\ForDisqus.wxr

It isn’t fancy and there is no error checking so it will either work or die horribly. If the latter, leave a comment and I’ll try to fix it for you.

Download BlogMLtoDisqus.exe. You’ll need to install .NET 4.0 as well if you don’t already have it.

Updated 2011-04-22: Added an optional third parameter that specifies the XML namespace for BlogML in case you need to override the default.

Here are two scenarios where merged ResourceDictionary objects are the way forward.

I’m working on a WPF project that needs to be single instance. Heaven forbid that the WPF team should pollute the purity of their framework with support for this kind of thing (or NotifyIcon support but that’s another story) so I’m using the code recommended by Arik Poznanski: WPF Single Instance Application. I like this because it both enforces a single instance and provides an interface that reports the command line passed to any attempt to launch another instance.

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WPF: When it's good it’s very, very good and when it’s bad it’s like sautéing your own eyeballs.

When you’re about to launch a process that will trigger an elevation prompt it’s polite to decorate it with the little UAC shield so the user knows what to expect. Of course there’s no such capability in WPF, and WPF controls have no handles so you can’t use SendMessage / BCM_SETSHIELD as with Windows Forms.

System.Drawing.SystemIcons.Shield seems promising, but it returns the wrong icon on Windows 7 (at least in .NET 4).

SHGetStockIconInfo will allow you to get the correct icon, but isn’t supported on Windows XP. I’ve just added the necessary interop signatures for SHGetStockIconInfo to pinvoke.net so I won’t duplicate that code here. Once you have the interop you can get the correct icon as a BitmapSource using the following code:

BitmapSource shieldSource = null;

if (Environment.OSVersion.Version.Major >= 6)
{
    SHSTOCKICONINFO sii = new SHSTOCKICONINFO();
    sii.cbSize = (UInt32) Marshal.SizeOf(typeof(SHSTOCKICONINFO));

    Marshal.ThrowExceptionForHR(SHGetStockIconInfo(SHSTOCKICONID.SIID_SHIELD,
        SHGSI.SHGSI_ICON | SHGSI.SHGSI_SMALLICON,
        ref sii));

    shieldSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(
        sii.hIcon,
        Int32Rect.Empty, 
        BitmapSizeOptions.FromEmptyOptions());

    DestroyIcon(sii.hIcon);
}
else
{
    shieldSource = System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(
        System.Drawing.SystemIcons.Shield.Handle,
        Int32Rect.Empty, 
        BitmapSizeOptions.FromEmptyOptions());
}

I've written an extension for BlogEngine.NET that automatically adds several different geographical tags to blog posts. I knocked this up for my Hikes blog. It might be useful for any blog where some of the posts are related to a real world location.

To get started download GeotagFromKML.zip (2.24 kb) and copy GeotagFromKML.cs to the App_Code\Extensions folder in your BlogEngine.NET instance.

The extension does two things. Firstly it looks for a link to a KML file when post is added or updated (it does this because each of my hike posts includes a Google Earth KML file for the hike). If a KML link is found then a paragraph is added to the post containing the longitude and latitude of the first coordinate in the KML file. The paragraph uses the Geo microformat. You can customize the text in settings for the extension. You can also regenerate by deleting the paragraph and saving the post. 

The second function is to add ICBM and Geo Tag META tags when serving a post that contains the geotagged coordinates. You can take advantage of this without linking to a KML file, just include a location like this in your post:

<span class="geo">
    <span class="latitude">37.754849</span>, 
    <span class="longitude">-122.446607</span>
</span>

Once you have geotagging up and running you might also want to add GeoURL to the list of ping services for your site.

.NET doesn’t support rebooting, logging off or shutting down your computer though a managed API. Searching for the best way to do this brings up three options: WMI, shutdown.exe and ExitWindowsEx.

I regard WMI as the last resort of the desperate. Weakly typed magic string juju.

Calling Process.Start(“shutdown.exe /r /t 0”) might work, but how would you know? And you’ve got the overheard of starting a new process just to accomplish a reboot. Lazy.

The best way to reboot is P/Invoke to ExitWindowsEx. Unfortunately there’s some really awful sample code out there which will either fail to do anything or mask any errors. I’ve included a drop-in class below that fixes these problems.

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Imperial Bedrooms by Bret Easton Ellis

4/5

Returns to the characters of Less Than Zero twenty five years later. I don't think it's a plot spoiler to say that they're not happy and well adjusted people. I found Glamorama to be pretty tedious and Lunar Park only marginally better. It was a huge relief that Imperial Bedrooms just flows. It's a welcome return to his earlier narrative style. Dread and paranoia are visceral presences from the start and then layers of fear and horror build until it can't get any worse and then somehow does. Brilliant.

 

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I'm slowly converting a number of blogs from Blogger to BlogEngine.NET. The least fun part is dealing with the Blogger export file. For this blog I used a Powershell script but had problems with comments not exporting correctly and it was quite painful to fix everything up. Blogger allows you to export a copy of your blog using ATOM, however BlogEngine.NET (and other tools) speak BlogML.

I've just released a command line tool that takes the ATOM format Blogger export and converts it to BlogML. You can download Blogger2BlogML from Codeplex. The tool uses .NET 4.0 (client profile) so you'll need to install this if you don't already have it. If you give Blogger2BlogML a try let me know how you get on.