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URI Percent Encoding Ignorance Level 2 - There is no Unencoded URI

2012 Feb 20, 4:00

As a professional URI aficionado I deal with various levels of ignorance on URI percent-encoding (aka URI encoding, or URL escaping).

Getting into the more subtle levels of URI percent-encoding ignorance, folks try to apply their knowledge of percent-encoding to URIs as a whole producing the concepts escaped URIs and unescaped URIs. However there are no such things - URIs themselves aren't percent-encoded or decoded but rather contain characters that are percent-encoded or decoded. Applying percent-encoding or decoding to a URI as a whole produces a new and non-equivalent URI.

Instead of lingering on the incorrect concepts we'll just cover the correct ones: there's raw unencoded data, non-normal form URIs and normal form URIs. For example:

  1. http://example.com/%74%68%65%3F%70%61%74%68?query
  2. http://example.com/the%3Fpath?query
  3. "http", "example.com", "the?path", "query"

In the above (A) is not an 'encoded URI' but rather a non-normal form URI. The characters of 'the' and 'path' are percent-encoded but as unreserved characters specific in the RFC should not be encoded. In the normal form of the URI (B) the characters are decoded. But (B) is not a 'decoded URI' -- it still has an encoded '?' in it because that's a reserved character which by the RFC holds different meaning when appearing decoded versus encoded. Specifically in this case, it appears encoded which means it is data -- a literal '?' that appears as part of the path segment. This is as opposed to the decoded '?' that appears in the URI which is not part of the path but rather the delimiter to the query.

Usually when developers talk about decoding the URI what they really want is the raw data from the URI. The raw decoded data is (C) above. The only thing to note beyond what's covered already is that to obtain the decoded data one must parse the URI before percent decoding all percent-encoded octets.

Of course the exception here is when a URI is the raw data. In this case you must percent-encode the URI to have it appear in another URI. More on percent-encoding while constructing URIs later.

PermalinkCommentsurl encoding uri technical percent-encoding

Capturing HTTPS with FiddlerCore

2011 Apr 6, 10:00

I used FiddlerCore in GeolocMock to edit HTTPS responses and ran into two stumbling blocks that I'll document here. The first is that I didn't check if the Fiddler root cert existed or was installed, which of course is necessary to edit HTTPS traffic. The following is my code where I check for the certs.

    if (!Fiddler.CertMaker.rootCertExists())
if (!Fiddler.CertMaker.createRootCert())
throw new Exception("Unable to create cert for FiddlerCore.");

if (!Fiddler.CertMaker.rootCertIsTrusted())
if (!Fiddler.CertMaker.trustRootCert())
throw new Exception("Unable to install FiddlerCore's cert.");

The second problem I had (which would have been solved had I read all the sample code first) was that my changes weren't being applied. In my app I only need the BeforeResponse but in order to modify the response I must also sign up for the BeforeRequest event and mark the bBufferResponse flag on the session before the response comes back. For example:

    Fiddler.FiddlerApplication.BeforeRequest += new SessionStateHandler(FiddlerApplication_BeforeRequest);
Fiddler.FiddlerApplication.BeforeResponse += new SessionStateHandler(FiddlerApplication_BeforeResponse);
private void FiddlerApplication_BeforeRequest(Session oSession)
if (IsInterestingSession(oSession))
oSession.bBufferResponse = true;
PermalinkCommentshttp fiddler technical https geolocmock programming fiddlercore

JavaScript & .NET interop via WebBrowser Control

2011 Apr 5, 10:00

For my GeolocMock weekend project I intended to use the Bing Maps API to display a map in a WebBrowser control and allow the user to interact with that to select a location to be consumed by my application. Getting my .NET code to talk to the JavaScript in the WebBrowser control was surprisingly easy.

To have .NET execute JavaScript code you can use the InvokeScript method passing the name of the JavaScript function to execute and an object array of parameters to pass:

new object[] {

The other direction, having JavaScript call into .NET is slightly more complicated but still pretty easy as far as language interop goes. The first step is to mark your assembly as ComVisible so that it can interact with JavaScript via COM. VS had already added a ComVisible declaration to my project I just had to change the value to true.

[assembly: ComVisible(true)]

Next set ObjectForScripting attribute to the object you want to expose to JavaScript.

this.webBrowser2.ObjectForScripting = this.locationState;

Now that object is exposed as window.external in JavaScript and you can call methods on it.

window.external.Set(lat, long, alt, gUncert);

However you don't seem to be able to test for the existence of methods off of it. For example the following JavaScript generates an exception for me even though I have a Set method:

if (window.external && window.external.Set) {
PermalinkCommentsjavascript webbrowser .net technical csharp

IE9 Document Mode in WebOC

2011 Apr 4, 10:00

Working on GeolocMock it took me a bit to realize why my HTML could use the W3C Geolocation API in IE9 but not in my WebBrowser control in my .NET application. Eventually I realized that I was getting the wrong IE doc mode. Reading this old More IE8 Extensibility Improvements IE blog post from the IE blog I found the issue is that for app compat the WebOC picks older doc modes but an app hosting the WebOC can set a regkey to get different doc modes. The IE9 mode isn't listed in that article but I took a guess based on the values there and the decimal value 9999 gets my app IE9 mode. The following is the code I run in my application to set its regkey so that my app can get the IE9 doc mode and use the geolocation API.

        static private void UseIE9DocMode()
RegistryKey key = null;
key = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Internet Explorer\\Main\\FeatureControl\\FEATURE_BROWSER_EMULATION", true);
catch (Exception)
key = Registry.CurrentUser.CreateSubKey("Software\\Microsoft\\Internet Explorer\\Main\\FeatureControl\\FEATURE_BROWSER_EMULATION");
key.SetValue(System.Diagnostics.Process.GetCurrentProcess().MainModule.ModuleName, 9999, RegistryValueKind.DWord);
PermalinkCommentsweboc fck ie document mode technical ie9

DVD Ripping and Viewing in Windows Media Center

2010 Aug 17, 3:05

I've just got a new media center PC connected directly to my television with lots of HD space and so I'm ripping a bunch of my DVDs to the PC so I don't have to fuss with the physical media. I'm ripping with DVD Rip, viewing the results in Windows 7's Windows Media Center after turning on the WMC DVD Library, and using a powershell script I wrote to copy over cover art and metadata.

My powershell script follows. To use it you must do the following:

  1. Run Windows Media Center with the DVD in the drive and view the disc's metadata info.
  2. Rip each DVD to its own subdirectory of a common directory.
  3. The name of the subdirectory to which the DVD is ripped must have the same name as the DVD name in the metadata. An exception to this are characters that aren't allowed in Windows paths (e.g. <, >, ?, *, etc)
  4. Run the script and pass the path to the common directory containing the DVD rips as the first parameter.
Running WMC and viewing the DVD's metadata forces WMC to copy the metadata off the Internet and cache it locally. After playing with Fiddler and reading this blog post on WMC metadata I made the following script that copies metadata and cover art from the WMC cache to the corresponding DVD rip directory.

Download copydvdinfo.ps1

PermalinkCommentspowershell wmc technical tv dvd windows-media-center

Kevin Frei @ NWCPP: Exception Handling Cost

2010 May 10, 7:23"Kevin Frei - Exception Hanlding Cost September 2006 meeting of the Northwest C++ Users Group. Discussion of the assembly language cost of exception handling on the x86 Windows and x64 Windows platform"PermalinkCommentsC++ programming language exception microsoft windows performance technical video

Presidential Election 2008 FAQ

2008 Oct 13, 10:53"This is an FAQ (Frequently Asked Questions list) for the 2008 United States Presidential Election. I need to disclose up front that I am an Obama supporter. However, with the exception of the very last question, this FAQ is designed as a collection of factual information (such as the latest poll results) and of analysis that is as objective as possible."PermalinkCommentsvia:kris.kowal politics election obama mccain

Dinner with Goodwins at Icon Grill

2008 Mar 27, 9:33

The Goodwin family, except for Michelle who is taking a class trip to Washington DC and New York, was in Seattle this week. Sarah and I met up with them for dinner last night at the Icon Grill. I enjoy the Icon Grill in general and last night was no exception especially having dinner with the Goodwins which was a lot of fun. It was particularly cold and at one point snowed. The Goodwin's are seeing all the classic tourist attractions in Seattle some of which are depicted in the following 1962 Seattle's Worlds Fair postcard. The postcard is featured on Paleo-Future and unsurprisingly the 1962 Worlds Fair favored Seattle's Space Needle and monorail.

[Icon Grill front. Licensed under under Creative Commons. By Troy B Thompson][Seattle's Worlds Fair Postcard]

PermalinkCommentsicon grill life washington goodwins sarah seattle nontechnical

Windows Media Center and Zune Integration Hack

2007 Nov 28, 1:23One of the new Zune features that had me the most excited was the claimed improved Windows Media Center integration which unfortunately turned out to simply mean support for the Win MCE video format (with an exception for HD). I wanted to be able to pick shows recorded by my Win MCE and have the Zune automatically sync up the latest episodes. However, with the improved podcast support in the Zune software one can easily create a ridiculous hack to accomplish this.

The new Zune software has podcast support which does everything I'd want to do with a Win MCE recorded TV series so the goal is to shoehorn a TV series into a Zune podcast. An overview of the steps: Create an XSLT that converts Win MCE data to a podcast, run the XSLT as a scheduled task every few hours per TV series, setup a Web server pointed at the resulting podcasts and the Win MCE Recorded TV directory, and subscribe to the resulting podcasts in the Zune software.
  1. Reading through the Win MCE data stored as an XML file in "C:\ProgramData\Microsoft\eHome\Recording\Recordings.xml" and the spec for podcasts I created an XSLT to convert a series from Win MCE data to a podcast.
  2. I added a new task to the Scheduled Tasks to run my XSLT using my xsltproc.js script. The task runs a handful of commands that look something like the following:

    C:\windows\system32\wscript.exe C:\users\dave\bin\xsltproc.js C:\Users\Dave\Documents\trunk\development\mce-zune\mce-to-podcast.xslt C:\ProgramData\Microsoft\eHome\Recording\Recordings.xml --param title "The Daily Show With Jon Stewart" --param max 4 --param baseURI "http://groucho/" --param thisRelURI "tds.xml" -o "D:\recorded tv\tds.xml"

    For each TV series I run a command like the above and that outputs a podcast for that series into my "D:\Recorded TV\" directory.
  3. Zune only allows http URIs for its podcasts so I installed a web server on my Win MCE server. I'm running Vista Ultimate so it was quick and easy for me to install IIS7 but any Web server will do. Then I pointed it at "D:\Recorded TV\".
  4. Once all the above was done I just subscribed to the resulting podcasts via my Web server and viola! Since I'm forced to use a Web server I can even run the Zune software on a machine other than my Win MCE server. You can see a screen-shot above of my Zune software showing my Colbert Report podcast.
PermalinkCommentstechnical xml mce hack windows media center zune windows xslt podcast
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