Scott Hanselman's ComputerZen.com

This is a complex topic, but here's a cursory explanation:

The Web Server, in this case IIS, sets Content Expiration info and information about then things are modified in the HTTP Headers.  If you ask for something from the Web Server, but you say "only if modified since..." they will pass back “Not-Modified” HTTP Headers to the Browser. You can see this even when hitting F5 to refresh the browser if you use a tool like ieHTTPHeaders (http://www.blunck.info/iehttpheaders.html) .  Look at IE Content Expiration in the Properties. 

Most folks like to have a “/images” folder that has SEPARATE Content Expiration settings and static content, or many levels of image volatility.

You have a few possible solutions:

·         Have volatile (often changing) images stored in one folder and set to expire immediately or on your specific schedule. 

·         Have the Browser user press CTRL-F5 to “blow through the cache”…F5 in IE will NOT fetch updated images until they expire. Pressing CTRL-F5 will keep the browser from including “If-Not-Modified” – which is equivalent to saying “get it anyway.”

·         Check the GET requests of your images in the HTTP Headers to see when they will expire...then wait. ;)

·         If you are generating the images yourself (dynamically generated on the server side) then you control the headers, so you can force updates by writing the appropriate headers yourself.

Notice in this screen shot that even though I pressed F5, the Web Server responded “This image hasn’t been modified!”

Even more, this request from the browser specified “Only give me this image if it’s been modified since a certain date.”

The moral of this story is, you'll never know the WHY of the behavior of your system unless you know both the HOW of the HTTP Spec and the QUIRKY HOW of the browser whose behavior you're examining.

Schema Versioning: Changing a namespace is not versioning, it is new type creation. [meta-douglasp]

Ok...I can see that point of view...then does versioning (as we hope to know it) simply not exist in the world of Schema?

Updated Thought: Certainly COM ProgIds like Word.Application.8 isn't "versioning," but rather new Type/Interface creation with versioning by allusion.

One of my heros (not cuz he can code, but boy, can he drink!) is Stephen Forte...he stole one of the Flat Juval Lowy Software Legends standups at TechEd (I was going to help, but I wimped out) and proceeded to take it on a whirlwind trip around Texas, including some of the nicer bathrooms...anyway, Stephen's put the pictures up, enjoy.

Someone wanted to know what the equivalent "preprocessor macros" in C# are for __FILE__ and __LINE__.  They watned to log the current file name and line number.  Note that the "1" as the first parameter to the StackFrame constructor tells it to skip ONE frame up the stack, while the true tells it to capture the file and line info.

[STAThread]
static void Main(string[] args)
{
     ReportError("Yay!");
}

static private void ReportError(string Message)
{
     StackFrame CallStack = new StackFrame(1, true);
     Console.Write("Error: " + Message + ", File: " + CallStack.GetFileName() + ", Line: " + CallStack.GetFileLineNumber());
}

This is not really technical or .NET related, but hey.  The signal-to-noise ratio is still high around here, eh? :)

So, my wife bought herself a Honda Civic Hybrid, as previously posted, and we need to sell her '97 Mitsubishi Mirage DE Coupe.  I suppose I could post adds on Vehix.com and http://www.oregonlive.com or <gasp> the newspaper.   But, I could also (possibly) take advantage of the power of Google, Weblogging and Keven Bacon and post the link here: http://www.computerzen.com/carforsale. 

Then, I sit back and hope that this thrilling blog post is linked to furiously, driving my site up the Google Page Ranks system to the point where ANYONE in Oregon who even THINKS, "Used Cars Oregon," "Good Used Car Oregon" or "Mitsubishi Oregon" will be magnetically sucked into my world and compelled to purchase.

Updates on this crucial experiment as the queries pour in.

Or, could I just use the Nickel Ads...