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Posted by Jukka K. Korpela on 03/22/07 15:29
Scripsit MG:
> The page in question (http://www.samurdermysteries.co.za/gal.htm)
> doesn't contain any pictures at all. It is a page of links. On this
> page I put new link to the newly created page containing the
> pictures. It is this page of links that has the problem. The newly
> created link is not visible to visitors who recently visited the page.
OK, so it is not about images at all. Whether the newly added link refers to
a page with images is immaterial, as is its being a link. So this is about
caching the HTML document. Then the classical advice is that you should read
the classical treatise on practical caching:
http://www.mnot.net/cache_docs/
To take a shortcut, you could first check the current cacheability, using
e.g.
http://www.ircache.net/cgi-bin/cacheability.py
This shows, in this case, that there is no explicit cacheability
information, and caches will probably make freshness guesses based on the
last modification of the page. For most purposes, this is just fine.
Authors often get wild about caches when they edit a page and have
difficulties in seeing the modified version. They don't realize that
visitors don't experience such problems. When I visit your page, I normally
get it from your server, though at times I might get it from my ISP proxy
cache if some other user visited it very recently, e.g. 10 minutes ago, and
in that case I would get it somewhat faster - and I might get it even when
your server is temporarily unreachable. The odds of getting an old version
that way are very small. But to the _author_, the situation is different.
Do you still want to defeat caching?
Note that nothing that you put into the HTML document can affect the way an
ISP's caching proxy works, for example, since the proxy doesn't even look at
the _content_, only HTTP headers.
--
Jukka K. Korpela ("Yucca")
http://www.cs.tut.fi/~jkorpela/
Join the Clueless Club by quoting this sig!
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