Worker Process Group in IIS 6 (Development | Web)

This is nothing new and it has probably been written about hundreds (if not thousands) of times already, but since I’m only encountering the issue every few months or even more seldom, it always slips my mind and I end up wondering what’s wrong.

I’m talking about the fact that any custom identity being used for an application pool in Internet Information Services 6.0 must be a member of the IIS_WPG group which grants it all the necessary privileges. Unfortunately otherwise IIS reports only Service Unavailable when the site gets accessed without any additional information which makes it kind of difficult to determine the cause of the problem.

Hopefully this post will help reminding me of this fact when I need it the next time.

5/19/2007 6:25:23 AM (Central Europe Standard Time, UTC+01:00)    Comments [0]

Running Windows Sidebar gadgets directly in IE7 (Development | Vista | Web)

Since gadgets are HTML applications and the Windows Sidebar uses Internet Explorer 7 to render them, I prefer running their code directly in IE7 during development. It makes debugging easier and allows me to develop them in Windows XP on my primary development machine with all the tools properly setup.

While this works great in early development stages, it becomes a problem later on when you start using the Windows Sidebar object model (to implement settings, visibility changes handlers etc.). This specific code understandably can only be debugged while running in Windows Sidebar but the unfortunate side effect is that the calls to objects which don’t exist in IE7 break the scripts and effectively prevent running the would-be gadget in IE7 even without this functionality.

The following function can help you keep the gadget running directly in IE7 even after the gadget specific functionalities are already implemented:

function isGadget()
{
    try
    {
        var dummy = System;
        return true;
    }
    catch (err)
    {
        return false;
    }
}

Just check if the application is running in Windows Sidebar at gadget startup and make sure to use the object model only when this is true. You can also add alternative initialization for running directly in IE7 to provide default values for settings and any other gadget specific variables. By doing this you can still test new features directly in IE7 if they are not gadget specific.

10/29/2006 2:11:59 PM (Central Europe Standard Time, UTC+01:00)    Comments [0]

A sample Windows Sidebar gadget (Development | Vista | Web | Downloads | Sources | Windows) HelloWorld.zip (3.99 KB)

The whitepaper sample code doesn’t exactly follow the guidelines for web development therefore I wrote my own sample with clearly separated HTML structure, CSS styles and JavaScript code. I decided to make it publicly available in case anyone else finds it useful. A few things are worth mentioning.

• Empty XHTML tags. For some reason the XHTML style empty tags don’t work as expected when they are filled from JavaScript code. It seems as if the engine would parse them as opened tags without the corresponding closing tag. Therefore you should always use the long form <span id=”mySpan”></span> instead of the short one <span id=”mySpan” />. This problem seems to be specific for gadgets. The same code runs just fine in IE7.
• Localization. I haven’t managed to get the localization to work at all. I suppose the engine uses the files from the locale directory corresponding to the current display language not the locale settings. This does make sense but with only English language available in Vista there’s no way to check that the current file organization in my sample gadget is really ok. I kept it in the sample since I’m pretty convinced that it is.
• Deployment. If you double click a file with a .gadget extension in Vista, you will automatically start the gadget installation process. The file needs to be a zip or cab archive containing the actual gadget directory structure. Vista behaves as if an application setup was started. This means that you should sign the file to increase the end user trust. You can use the Sign Tool to do that but in this case you need to make a cab file since zip files can’t be signed with it. I tried to make the cab file using a CAB Project template in Visual Studio 2005 but I couldn’t make the correct directory structure. I ended up using Cabarc. After all, I only had to run the following line in the gadget directory to build the cab file correctly.
  cabarc –p –r N ..\HelloWorld.gadget *

10/22/2006 1:14:03 PM (Central Europe Standard Time, UTC+01:00)    Comments [0]

Writing your first Windows Sidebar gadget (Development | Vista | Web)

This whitepaper should definitely be your first source of information when starting with gadget development. Unfortunately I didn’t find it as helpful as it could be. Find below a few issues that could be covered better since I’ve been struggling with them for some time before I get everything to work as expected.

• The style definition for body in both pages is missing the unit – px. Without it the definition is invalid and the gadget shows up with minimum size. The correct style definition would be in the likes of:
  body
  {
     width: 130px;
     height: 50px;
  }
• The settingsUI property is a member of System.Gadget not System.Gadget.Settings. This time the error is in the reference not the whitepaper.
• If you’re only replacing the files in the C:\Users\<username>\AppData\Local\Microsoft\Windows Sidebar\Gadgets directory to update the gadget you might have some problems with caching even if you close all gadget instances as the whitepaper suggests. In my case the old image files and gadget.xml file were still used although they have been replaced. Restarting Windows Sidebar should help.
• Don’t forget that gadget settings are stored with a particular gadget instance. This makes it possible to display two instances of the gadget with different settings. The side effect is that they get lost every time you remove the gadget from the sidebar and put it back on. It works like that by design and if you need persistent common settings for all instances you’ll have to use a different solution.

10/22/2006 12:48:31 PM (Central Europe Standard Time, UTC+01:00)    Comments [0]

Resources for Windows Sidebar gadget development (Development | Vista | Web)

I though I’d gather in one place all the useful links I found with information on development of Windows Sidebar gadgets.

• Gadget Development Overview whitepaper should be you first stop. It’s a short article explaining the basics of gadget development.
• Windows Sidebar Reference is the only documentation that is currently available. It’s not very detailed, neither always accurate but it should still serve you well.
• Gadget Corner is a blog maintained by the Windows Sidebar team. It contains a few articles with information that can’t be found anywhere else.
• Sidebar Gadgets Forum is the only forum dedicated to gadget development. On top of that the Windows Sidebar team members have the habit of answering the posted questions.

10/22/2006 12:40:45 PM (Central Europe Standard Time, UTC+01:00)    Comments [0]

Downloading template files from web server (Development | Web | Personal | Website)

Be careful when hosting your web site based on DasBlog from a Windows XP machine. While IIS 6 in Windows 2003 prevents the download of files with unknown extensions by default, the IIS 5.1 in Windows XP allows downloading such files. In the case of DasBlog all *.blogtemplate files are at risk. There are a few sites out there where these files can be downloaded. Although this probably isn’t a big security risk it might be something you want to prevent. Probably the easiest way to do that is by modifying the web.config file. You should add the following line at the end of the <httpHandlers> section:

<add verb="*" path="*.snippet" type="System.Web.HttpForbiddenHandler" />

6/10/2006 10:56:44 PM (Central Europe Standard Time, UTC+01:00)    Comments [0]

DasBlog macro development (Development | .NET | Web | Personal | Website)

6/10/2006 10:42:10 PM (Central Europe Standard Time, UTC+01:00)    Comments [0]

Redirecting web pages to specific addresses (Development | Web)

The problem is pretty straightforward: the web site redesign causes the structure to change, thus the old addresses become invalid. Since you don’t want the users to get the dreaded error 404: Object not found, there are a couple of options available to you (if you’re using IIS – Internet Information Services, that is).

You could just change the error page to match the style of your web site and inform the visitor about the now missing page or just make the redirection to your new starting page. This is a bit unfriendly to the visitors if you kept the old content since they have to find it themselves. It would certainly be better to redirect them directly to the new address of the old content. But still it’s not a bad idea to do this. It’s an easy way to keep the users on your website even when they encounter invalid URLs by whatever reason. Just open up the Custom Errors tab of the virtual directory or web site properties and set the desired URL for the error 404. But don’t forget that you have to enter the complete path starting from the root of the site, for example: "/mydirectory/myurl.html".

If you want to make a different redirection for each page you could just keep the old pages but instead of having any actual content they would just make a redirection to the correct new address. This solution has two problems:

• It’s difficult to maintain if you have many pages.
• You’re stuck with the client side redirection, i.e. meta refresh tag.

To make the redirection server side you could use the redirect options on the Home Directory tab of the virtual directory or web site properties. But they have some serious limitations and tend not to work as expected, even more so because the documentation doesn’t explain them very well. But there’s no reason to worry, I have a better solution for you. Setup a special 404 URL on the Custom Errors tab as already suggested. But this time use an asp or aspx page for it. The supplied query string (Request.QueryString) contains the missing URL which you can parse out and use to determine the correct new address corresponding to it. For a few pages a simple select or switch clause will do but nothing prevents you from having the mappings stored externally, in a special file or a database table for example. All that’s left is to make a Response.Redirect to the new address.

There’s one more thing to take care of. If you moved your site to a new subdirectory and chose the last suggested solution, don’t forget to setup a similar simple starting page which just redirects the visitors to the new starting page. Trying to open the site without this page will namely cause an error 403: Forbidden, because a directory listing will be attempted which you have (hopefully) prevented.

Thanks go to Peter Forret for some of the ideas I used to make this work when redesigning my page.

1/19/2006 11:35:50 PM (Central Europe Standard Time, UTC+01:00)    Comments [1]