When web servers were first built, there was a one-to-one mapping between virtual files (i.e. addressable via http) and the physical files (the ones in the file system). Over time, two important capabilities were added. First, the contents of a given file became dynamic. So while you the reader always come back to default.aspx (or rss.aspx as the case may be) the content changes everytime I post something new. Secondly, the physical file dependency was removed. It’s not used much in dasBlog, but in .TEXT this is very prevelant. My last post on blogs.msdn.com is located at http://blogs.msdn.com/devhawk/archive/2005/02/01/364380.aspx. Obviously, there is no actual file named 364380.aspx, .TEXT uses the filename as a key into the DB to find the actual entry content. This technique is used extensively in the new MSDN2 (if you haven’t already, check out Tim Ewald’s MSDN Magazine article about URL design for MSDN2).
So now for the funky idea part – why couldn’t we generate dynamic local files the same way? I’m not sure I’ve got a great use for this yet – most of the apps I use are programmable to some extent, so dynamic content can be generated at the app level rather than at the file system level. But I’m thinking there may be some scenarios where it would make sense to do this at the file system. For example, in the new Winter Fun Pack there’s a new version of the WMP blogging plugin that autoupdates the Outlook and Outlook Express signature files whenever the song being played changes (a la Duncan’s Coding4Fun article). But with virtual files in the file system, you could generate these files when they are accessed instead of writing new ones everytime the song changes, even if Outlook open.
Of course, our local file system typically has more writing activity than the web, so I’m thinking this isn’t that great an idea. But I figured I’d share in case someone else could think of some good uses. Or maybe this already exists and I just don’t know about it.
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