|
North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: decreased caching efficiency?
On Fri, Oct 20, 2000, Dana Hudes wrote: > > >When I switch to CGI-based delivery of images the cache will of course > > >become pass-through > > >since there will be no file to cache just a stream of bytes.... > > > > Is the assumption there that by using CGI you'll automatically tweak a > > configuration in a caching proxy? If so then it's a flawed assumption. > > > But there is no file to cache? I don't have enough gear to set up a test with squid myself > (and that would only be one cache) but how is the engine to know to cache it? > My understanding is that CGI-generated content is usually not cached. BZZT. Another assumption which is actually totally not true. For example, imagine your photo book. The photos won't change, right ? The position in your database won't change, right ? So .. http://www.domain.com/photos?id=31765 ok. 31765 is a static image that won't change. So, you'd be better off setting its expiry time to something high, wouldn't you? > > Having had a very quick look at your site, it seems a little strange that > > you want to defeat caching of those objects that soak up bandwidth; the > > request to perform "click-through" on the advert suggests that you're using > > the revenue to pay for your bandwidth costs. (So, one assumes that the > > more the material was cached, the less you'd have to pay, and the less > > you'd have to worry about page impressions.) I particularly like the way > > that you require my browser to send a Referer field to be allowed to view > > the pictures ;-) > > I do indeed use the revenue to pay for bandwidth but the pictures, by and large > (its a work in progress) have been tuned for file size; still takes time to decompress but hey, > what can I do. Also the projected load vs. the bandwidth is such that I have a LOT more room left. The users get a reasaonbly large bitmap in a reasonably small file. ImageMagick is nifty set of programs. The problem I have is pirates who collect images and use them for other purposes. > the pictures...well, I actually don't want them hanging around on the user's disk once the browser is no longer on the page. > I haven't figured out how to make that happen other than expiration of 1 minute or something. You can't. End of story. This is the internet, people control their end-nodes, so you have zero chance of this happening. If you *REALLY* want to be evil, you wrap the images in a java applet so they can't just rightclick on it, but again that won't stop the smart people. Adrian -- Adrian Chadd The Law of Software Development and <[email protected]> Envelopment at MIT: "Every program in development at MIT expands until it can read mail."
|