For sites powered by the Pencilneck CMS, we’ve for ages and ages had what we called “Friendly URLs”. These are common across CMS’s, blogs, etc (some ironically, I don’t use them on Tannock.net because I’m too lazy to reconfigure my config & htaccess files). Back in the day, we did this by physically writing a folder to the server. Which was not ideal. So we then switched to redirected using ColdFusions onMissingTemplate() handler. In this instance, we have the IIS server trigger a 404 error, which calls a custom CFM file, which does not, in fact, exist. This triggers the sites onMissingTemplate() handler to actually read the URL and load up the appropriate page from the DB. This works well, but there’s a fair amount of overhead. Vs. the physical stub option, it added between 400-600 ms – not a huge amount, but enough to cause a noticeable overhead on busy sites.
But a while back for a larger project, we installed the Helicon ISAPI rewrite module for IIS. I’ve been using this for a variety of things on sites, such as locking down directories for documents, redirecting particular scripts elsewhere, etc. But I hadn’t set it up to handle our friendly URL system.
This past weekend, I finally spent the time to test out the difference – and it’s impressive. Despite running exactly the same script as the current OnMissingTemplate() handler calls, it runs much faster – on average, 80-100 ms (vs. 400-600 previously) – a significant decrease – I’m guessing because there’s overhead from IIS to generate the 404, hand that off to the custom 404 page, which doesn’t exist, so hands it off to the onMissingTemplate() handler which then calls this script. Now, the the ISAPI rewrite condition kicks in and it calls the script directly.
And now all of our sites are slightly more responsive, which is better for everyone!